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Problems

Poor or rough idle

PLEASE USE PHOTOS TO IDENTIFY CORRECT ECU FOR YOUR VEHICLE

RANGE ROVER 3.5 (to 1990), ROVER SD1, TVR and MORGAN V8 (3.5 LITRE ENGINE – NON CAT) fitted with LUCAS 4CU fuel injection ECU and moving flap airflow meter, 1985-1989. ECU part numbers PRC 4764/7440/others. ECU is large rectangular alloy box with 6 bolts retaining top and bottom covers and is located under front r/h seat. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 4CU fuel injection ECU fitted on 3.5 vehicles up to late 1989 – click here to see photo – has proved to be extremely unreliable and virtually all engine idling/running problems are likely to be due to faults with this ECU. This is unfortunate because the system design is very good and a 3.5 Range Rover with a rebuilt ECU has excellent performance with economy of about 23 mpg in normal use.

The airflow meter is the most reliable part of the system and should NEVER be forced open and cleaned or lubricated internally – the carbon track is meant to look scored through! Please click here if you think your airflow meter has been tampered with. Please click here if your vehicle is converted to run on LPG gas.

FUEL CONSUMPTION OF LESS THAN 16 MPG IS CERTAIN CONFIRMATION OF ECU PROBLEMS.

Car Electronic Services specialises in the performance rebuilding of these ECUs during which the ECU electronics undergo comprehensive re-engineering to restore the ECU to its intended power specification. Many owners have written in saying how delighted they are with the added power and economy of their Range Rovers following performance rebuilds and have reported 22 to 25 mpg in normal use with crisp throttle response and very high top speeds. Our performance rebuilds are guaranteed for 24 months. Surprisingly, about 50% of our performance rebuild customers already have LPG gas conversions. Please find below our performance rebuild quotation request form.

Vehicles may exhibit more than one of the following symptoms. PLEASE NOTE – These are not the only failure symptoms – just the symptoms most likely to baffle!

Symptom 1

POOR OR ROUGH IDLE – vehicle can be OK for short while following service or tune up (vehicle does not retain CO setting – CO goes high/car runs very rich or can go to the other extreme – very weak).

Diagnostic Checklist
1a. Carry out hydrocarbons dye test on coolant (identifies head gasket problems). This test should be carried out out whenever there are idling or running problems with Rover V8 engines.

1b. Physically check throttle sensor rotation (should be smooth). Check output voltage at idle – should be between .3V and .36V. Adjust if necessary.

1c. ALWAYS REPLACE water temperature sensor. (the one behind the easy one!)1d. Check for sticking/rough airflow meter flap operation.1e. Ignition advance timing and spark OK?1f. If above check out OK then ECU is faulty.

Engine idle speed hunts (sometimes stalls) during warm up or when hot

RANGE ROVER 3.5 (to 1990), ROVER SD1, TVR and MORGAN V8 (3.5 LITRE ENGINE – NON CAT) fitted with LUCAS 4CU fuel injection ECU and moving flap airflow meter, 1985-1989. ECU part numbers PRC 4764/7440/others. ECU is large rectangular alloy box with 6 bolts retaining top and bottom covers and is located under front r/h seat. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 4CU fuel injection ECU fitted on 3.5 vehicles up to late 1989 – click here to see photo – has proved to be extremely unreliable and virtually all engine idling/running problems are likely to be due to faults with this ECU. This is unfortunate because the system design is very good and a 3.5 Range Rover with a rebuilt ECU has excellent performance with economy of about 23 mpg in normal use.

The airflow meter is the most reliable part of the system and should NEVER be forced open and cleaned or lubricated internally – the carbon track is meant to look scored through! Please click here if you think your airflow meter has been tampered with. Please click here if your vehicle is converted to run on LPG gas.

FUEL CONSUMPTION OF LESS THAN 16 MPG IS CERTAIN CONFIRMATION OF ECU PROBLEMS.

Car Electronic Services specialises in the performance rebuilding of these ECUs during which the ECU electronics undergo comprehensive re-engineering to restore the ECU to its intended power specification. Many owners have written in saying how delighted they are with the added power and economy of their Range Rovers following performance rebuilds and have reported 22 to 25 mpg in normal use with crisp throttle response and very high top speeds. Our performance rebuilds are guaranteed for 24 months. Surprisingly, about 50% of our performance rebuild customers already have LPG gas conversions. Please find below our performance rebuild quotation request form.

 

Symptom

ENGINE IDLE SPEED HUNTS (sometimes stalls) DURING WARM UP OR WHEN HOT – vehicle can actually rock. CO can be very low and unadjustable.

Diagnostic Checklist

1a. Physically check throttle sensor rotation (should be perfectly smooth). Check output voltage at idle – should be between .3V and .36V. Adjust if necessary.

1b. ALWAYS REPLACE water temperature sensor – the one behind the easy one!
1c. If above check out OK then ECU is faulty.

Vehicle hesitates then surges forward when pulling away from stop

RANGE ROVER 3.5 (to 1990), ROVER SD1, TVR and MORGAN V8 (3.5 LITRE ENGINE – NON CAT) fitted with LUCAS 4CU fuel injection ECU and moving flap airflow meter, 1985-1989. ECU part numbers PRC 4764/7440/others. ECU is large rectangular alloy box with 6 bolts retaining top and bottom covers and is located under front r/h seat. Click here to see photographs of ECU and airflow meter for this system

The Lucas 4CU fuel injection ECU fitted on 3.5 vehicles up to late 1989 – click here to see photo – has proved to be extremely unreliable and virtually all engine idling/running problems are likely to be due to faults with this ECU. This is unfortunate because the system design is very good and a 3.5 Range Rover with a rebuilt ECU has excellent performance with economy of about 23 mpg in normal use.

The airflow meter is the most reliable part of the system and should NEVER be forced open and cleaned or lubricated internally – the carbon track is meant to look scored through!Please click here if you think your airflow meter has been tampered with. Please click here if your vehicle is converted to run on LPG gas.

FUEL CONSUMPTION OF LESS THAN 16 MPG IS CERTAIN CONFIRMATION OF ECU PROBLEMS.

Car Electronic Services specialises in the performance rebuilding of these ECUs during which the ECU electronics undergo comprehensive re-engineering to restore the ECU to its intended power specification. Many owners have written in saying how delighted they are with the added power and economy of their Range Rovers following performance rebuilds and have reported 22 to 25 mpg in normal use with crisp throttle response and very high top speeds. Our performance rebuilds are guaranteed for 24 months. Surprisingly, about 50% of our performance rebuild customers already have LPG gas conversions. Please find below our performance rebuild quotation request form.

 

Symptom

ENGINE IDLE SPEED HUNTS (sometimes stalls) DURING WARM UP OR WHEN HOT – vehicle can actually rock. CO can be very low and unadjustable.

Diagnostic Checklist

2a. Physically check throttle sensor rotation (should be perfectly smooth). Check output voltage at idle – should be between .3V and .36V. Adjust if necessary.

2b. ALWAYS REPLACE water temperature sensor – the one behind the easy one!

2c. If above check out OK then ECU is faulty.

Vehicle breaks down at irregular intervals whilst driving but restarts ok

RANGE ROVER 3.5 (to 1990), ROVER SD1, TVR and MORGAN V8 (3.5 LITRE ENGINE – NON CAT) fitted with LUCAS 4CU fuel injection ECU and moving flap airflow meter, 1985-1989. ECU part numbers PRC 4764/7440/others. ECU is large rectangular alloy box with 6 bolts retaining top and bottom covers and is located under front r/h seat. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 4CU fuel injection ECU fitted on 3.5 vehicles up to late 1989 – click here to see photo – has proved to be extremely unreliable and virtually all engine idling/running problems are likely to be due to faults with this ECU. This is unfortunate because the system design is very good and a 3.5 Range Rover with a rebuilt ECU has excellent performance with economy of about 23 mpg in normal use.

The airflow meter is the most reliable part of the system and should NEVER be forced open and cleaned or lubricated internally – the carbon track is meant to look scored through!Please click here if you think your airflow meter has been tampered with. Please click here if your vehicle is converted to run on LPG gas.

FUEL CONSUMPTION OF LESS THAN 16 MPG IS CERTAIN CONFIRMATION OF ECU PROBLEMS.

Car Electronic Services specialises in the performance rebuilding of these ECUs during which the ECU electronics undergo comprehensive re-engineering to restore the ECU to its intended power specification. Many owners have written in saying how delighted they are with the added power and economy of their Range Rovers following performance rebuilds and have reported 22 to 25 mpg in normal use with crisp throttle response and very high top speeds. Our performance rebuilds are guaranteed for 24 months. Surprisingly, about 50% of our performance rebuild customers already have LPG gas conversions. Please find below our performance rebuild quotation request form.

Symptom

VEHICLE BREAKS DOWN AT IRREGULAR INTERVALS WHILST DRIVING BUT RESTARTS OK. Engine cuts out whilst driving – period of cut out can be 1 to 20 seconds, sometimes much longer.

Diagnostic Checklist

1a. Disconnect cold start injector and carry out extensive road testing. If problem does not recur, then cold start thermotime switch suspect.

2b. Before condemning ECU, carry out close physical inspection of ECU wiring loom at engine bulkhead. There are rare reports of chafing damage at this point which intermittently earths injectors-to-ECU wiring causing continuous operation of injectors.

3c. If above check out OK then ECU is faulty.

Engine starts ok and idles ok but sometimes dies the moment the accelerator is pressed

RANGE ROVER 3.5 (to 1990), ROVER SD1, TVR and MORGAN V8 (3.5 LITRE ENGINE – NON CAT) fitted with LUCAS 4CU fuel injection ECU and moving flap airflow meter, 1985-1989. ECU part numbers PRC 4764/7440/others. ECU is large rectangular alloy box with 6 bolts retaining top and bottom covers and is located under front r/h seat. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 4CU fuel injection ECU fitted on 3.5 vehicles up to late 1989 – click here to see photo – has proved to be extremely unreliable and virtually all engine idling/running problems are likely to be due to faults with this ECU. This is unfortunate because the system design is very good and a 3.5 Range Rover with a rebuilt ECU has excellent performance with economy of about 23 mpg in normal use.

The airflow meter is the most reliable part of the system and should NEVER be forced open and cleaned or lubricated internally – the carbon track is meant to look scored through!Please click here if you think your airflow meter has been tampered with. Please click here if your vehicle is converted to run on LPG gas.

FUEL CONSUMPTION OF LESS THAN 16 MPG IS CERTAIN CONFIRMATION OF ECU PROBLEMS.

Car Electronic Services specialises in the performance rebuilding of these ECUs during which the ECU electronics undergo comprehensive re-engineering to restore the ECU to its intended power specification. Many owners have written in saying how delighted they are with the added power and economy of their Range Rovers following performance rebuilds and have reported 22 to 25 mpg in normal use with crisp throttle response and very high top speeds. Our performance rebuilds are guaranteed for 24 months. Surprisingly, about 50% of our performance rebuild customers already have LPG gas conversions. Please see below for performance rebuild quotation request form.

Symptom

ENGINE STARTS AND IDLES OK BUT SOMETIMES DIES THE MOMENT THE ACCELERATOR IS PRESSED. Restarting can be accompanied by clouds of black smoke.

Diagnostic Checklist

1a. Check for wiring loom damage at throttle body linkage. There are rare reports of wiring damage caused by throttle cam chafing loom which intermittently earths injectors-to-ECU wiring causing continuous operation of injectors.

1b. If above checks out OK then ECU faulty.

Over rich or poor running following work in engine compartment, usually battery change

NORTH AMERICAN RANGE ROVER (3.5 LITRE ENGINE – WITH CAT) DURING THE PERIOD 1985 TO 1989 (approx) 3.5 litre Range Rovers were produced with the Lucas 13CU hot wire airmass fuel injection system for the North American market. This system can be identified by the ECU which is a large pressed steel (painted black) rectangular box with top cover held in place by 4 ‘pop’ rivets. We believe this system was only shipped to North American markets but please email if you know better! Part numbers PRC 6977/5053/others. Please click here to see photo of this ECU.

The Lucas 13CU ‘hot wire’ airmass system was fitted to North American and Swiss market 3.5 litre Range Rovers during the period 1987 – 1990. This system can be identified by the ECU which is a large pressed steel (painted black) rectangular box with top cover held in place by 4 ‘pop’ rivets. We believe this system was only shipped to North American (LA?) and Swiss markets but please email if you know better! Part numbers PRC 6977/5053/others. Please click here to see photo of this ECU.

There is one common problem associated with this system – over rich or poor running following work in engine compartment, usually battery change. We now offer a repair and rebuild service for this ECU. Please see below for repair quote form.

Intermittent running problems – such as running rich or cutting out for short periods

DISCOVERY WITH 3.5 OR 3.9 LITRE ENGINE (CAT & NON CAT) fitted with Lucas 14CU fuel injection ECU and hot wire airmass meter, 1990 to 1995. ECU part numbers PRC 8138/9059/others(3.5) and PRC 9010/others(3.9). During manufacture of these model ranges, AMR prefix part numbers were introduced. ECU is black painted cast alloy box with 4 cover retaining screws. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 14CU ‘hot wire’ airmass system ECU has proved to be more reliable than the earlier ‘moving flap’ airflow system 4CU ECU. Please click here for ECU photo. A common ECU problem we see is loss of 1 (or both) injector banks (usually following work in engine compartment) This failure is relatively easy to diagnose (check for injector pulses).

Early 3.9 ECU type number PRC7081 (superceded by PRC9061) develops a misfire at 2,800rpm (most noticeable at motorway speeds when overtaking). We now have a fix for this.

14CU ECUs as a group can suffer from intermittent running problems – such as running rich or cutting out for short periods – which are very difficult to diagnose so when there are vehicle problems we STRONGLY recommend road testing with a substitute before condemning your ECU.

Air mass meters are also causing running problems as vehicles age. Again, because diagnosis is so difficult, we STRONGLY recommend road testing road with a substitute before condemning air mass meter.

IN ALL CASES OF HOTWIRE system 3.5/3.9 vehicles (from 1990) WITH IDLING OR RUNNING PROBLEMS REFER TO THE DIAGNOSTIC CHECKLIST BELOW BEFORE PROCEEDING.

Diagnostic Checklist

In all cases poor idling or running problems with ‘hot wire’ system (from 1990), we recommend carrying out the following checks/tests before commencing diagnosis;

1) Check security and condition of all wiring and connectors associated with idle control valve.

2) Clean (with carb cleaner) and lubricate stepper motor and idle valve, clean and lubricate throttle butterfly housing as carbon build up can interfere with idle settings.

3) Carry out hydrocarbon dye test on coolant to identify head gasket problems. This test should be carried out whenever there are idle/running problems with Rover V8 engines.

4) Check correct operation of ignition advance/retard mechanism. Early mechanical systems should be cleaned and lubricated. DO NOT REMOVE DISTRIBUTOR FROM ENGINE BLOCK!

5) ALWAYS CHANGE engine coolant temperature sensor (the one behind the easy one!)

 

We have a repair and rebuild service for these ECUs – Please use our repair quote form.

 

Intermittent running problems

RANGE ROVER WITH 3.9/4.0/4.2 LITRE ENGINE (CAT & NON CAT) fitted with Lucas 14CU fuel injection ECU and hot wire airmass meter, 1990 to 1995. ECU part numbers PRC 6999/7081 – superceded by 8702 and 9061/ 9611/9515/others. During manufacture of these model ranges, AMR prefix part numbers were introduced. ECU is black painted cast alloy box with 4 cover retaining screws. Click here to see photographs of ECU and airflow meter for this system.

The Lucas 14CU ‘hot wire’ airmass system ECU has proved to be more reliable than the earlier ‘moving flap’ airflow system 4CU ECU. Please click here for ECU photo. A common ECU problem we see is loss of 1 (or both) injector banks (usually following work in engine compartment) This failure is relatively easy to diagnose (check for injector pulses).

Early 3.9 ECU type number PRC7081 (superceded by PRC9061) develops a misfire at 2,800rpm (most noticeable at motorway speeds when overtaking). We now have a fix for this.

14CU ECUs as a group can suffer from intermittent running problems – such as running rich or cutting out for short periods – which are very difficult to diagnose so when there are vehicle problems we STRONGLY recommend road testing with a substitute before condemning your ECU.

Air mass meters are also causing running problems as vehicles age. Again, because diagnosis is so difficult, we STRONGLY recommend road testing road with a substitute before condemning air mass meter.

IN ALL CASES OF HOTWIRE system 3.5/3.9 vehicles (from 1990) WITH IDLING OR RUNNING PROBLEMS REFER TO THE DIAGNOSTIC CHECKLIST BELOW BEFORE PROCEEDING.

Diagnostic Checklist

In all cases poor idling or running problems with ‘hot wire’ system (from 1990), we recommend carrying out the following checks/tests before commencing diagnosis;
1) Check security and condition of all wiring and connectors associated with idle control valve.

2) Clean (with carb cleaner) and lubricate stepper motor and idle valve, clean and lubricate throttle butterfly housing as carbon build up can interfere with idle settings.

3) Carry out hydrocarbon dye test on coolant to identify head gasket problems. This test should be carried out whenever there are idle/running problems with Rover V8 engines.

4) Check correct operation of ignition advance/retard mechanism. Early mechanical systems should be cleaned and lubricated. DO NOT REMOVE DISTRIBUTOR FROM ENGINE BLOCK!

5) ALWAYS CHANGE engine coolant temperature sensor (the one behind the easy one!)

 

We have a repair and rebuild service for these ECUs – Please see below for repair quote form.

Rough running on one bank of cylinders following work on the engine

RANGE ROVER WITH 4.6 LITRE ENGINE fitted with GEMS engine management ECU. ECU has cast alloy frame with pressed steel anodised covers. There are three distinctive 36 way connectors on one side. ECU part numbers are prefixed AMR. Click here to see photograph of ECU for this system.

The GEMS system introduced with the ‘new shape’ 4.6 litre Range Rover is an integrated engine management system (combining for the first time ignition and fuel injection functions in one box) and replaces the earlier Lucas 14CUX system. Please click here to see photo of this ECU.

The ignition part of the GEMS system comprises 4 coils, each providing a spark to 2 cylinders simultaneously on the wasted spark principle. (each spark plug is fired twice per cycle, once on compression and once on exhaust – the spark during exhaust cycle is not needed eg. it is ‘wasted’. This system saves costs as one coil can be used for 2 cylinders.

The fuel injection part is genuine multipoint ie. each cylinder injector is operated independently of the others and for the first time, Range Rover have an engine management system that is capable of controlling engines on a per cylinder basis.

GEMS is controlled by, and communicates with the BeCM and is integrated with the vehicle security systems.

To date, GEMS appears very reliable and the only common problem appearing is ECU damage following work on the catalysts or oxygen sensors. The symptoms of this are rough running on one bank of cylinders following work on the engine.

Please see below for a repair quotation form.

 

Engine cranks but does not start, fuel pump MAY not operate

Landrover 300TDi(non EGR), Discovery 300TDi(non EGR) and V8 MFi model years 1996 to 1999 are suffering problems with the security system ‘spider’ ECU located within the passenger compartment. This system communicates with the vehicle Theft Alarm Unit and enables power to the starter solenoid, fuel pump and ignition coil (V8 MFi) or starter solenoid and fuel cut off solenoid (300TDi). The ‘spider’ ECU is a small rectangular black plastic box with 10 pin connector and is mounted behind a steel plate underneath the radio. Access requires removal of the entire dashboard! Click here to see photograph of this ECU.

This system MAY have been fitted to a few Range Rover models immediately before the new shape models. Please email if you can identify Range Rover models with this ECU.

Discovery MFi-V8 Symptom 
Engine cranks but does not start, fuel pump MAY not operate. Breakdown services diagnose non start caused by weak or no spark. There can be a history of intermittent non-start. GAS CONVERSION VEHICLES CAN SUFFER OCCASIONAL DAMAGING BLOWBACKS WHEN RUNNING ON GAS.

Car Electronic Services now offer a low-cost re-engineering service for these ECUs involving fitting significantly upgraded components. Please fill out our quotation request form.

 

 

Engine sometimes does not crank, fuel solenoid MAY not operate

Landrover 300TDi(non EGR), Discovery 300TDi(non EGR) and V8 MFi model years 1996 to 1999 are suffering problems with the security system ‘spider’ ECU located within the passenger compartment. This system communicates with the vehicle Theft Alarm Unit and enables power to the starter solenoid, fuel pump and ignition coil (V8 MFi) or starter solenoid and fuel cut off solenoid (300TDi). The ‘spider’ ECU is a small rectangular black plastic box with 10 pin connector and is mounted behind a steel plate underneath the radio. Access requires removal of the entire dashboard! Click here to see photograph of this ECU.

This system MAY have been fitted to a few Range Rover models immediately before the new shape models. Please email if you can identify Range Rover models with this ECU.

Discovery 300TDi Symptom 
Engine sometimes does not crank, fuel solenoid MAY not operate. Immobiliser symbol light on dashboard MAY illuminate (Disco only). There can be a history of intermittent starting problems.

Car Electronic Services now offer a low-cost re-engineering service for these ECUs involving fitting significantly upgraded components. Please click here for quotation request form.

 

 

Engine cranks AT FULL SPEED but does not start. There may have been a history of intermittent difficult starting

We have had reports from several sources now that Discovery TDi 5 from 1998 to date are suffering starting problems which may be related to electrical noise radiating from the starter motor cable and interfering with the vehicle immobiliser. The fix appears to be fitting new starter motor even though it appears ok and cranks at full speed.

If you have any experience of this or can throw any light on this problem please email me from this page.

SYMPTOM

Engine cranks AT FULL SPEED but does not start. There may have been a history of intermittent difficult starting.

DIAGNOSTIC CHECKLIST

1) Confirm starter crank speed above 300RPM, if necessary fit new battery.
2) Confirm vehicle will start easily from push start or tow (DO NOT PUSH OR TOW AUTOMATICS!). if yes, try replacing starter motor with new.

Misfire in engine speed range 1500 to 2500 rpm

We have reported problems with misfire on the Range Rover 4 litre up to introduction of distributorless engine management systems.

Symptom

Misfire in engine speed range 1500 to 2500 rpm. Possible cause is alternator cabling running too close to distributor body. Inductive pick up seems to throw the ignition trigger pulses.

Misfire at idle

We have reported problems with misfire on the Range Rover 4 litre up to introduction of distributorless engine management systems.

Symptom

Misfire at idle. Possible cause is ignition reluctor pick up air clearance. Try resetting as per workshop manual.

LPG Gas Conversion Problems

Please check here for late model (1996-9) Landrover and Discovery MFi V8 with blowback problems whilst running on gas.

For some years we have seen many airflow meters from LPG gas converted 3.5 models that have suffered physical damage due to induction side blowback. This forces the airflow meter flap backwards and results in distortion of the flap spindle. A possible cause is lean running when switching from LPG to petrol (or vice versa) with engine running. Later type hot wire airmass meters are also suffering blowback damage.

Blowback damage to airflow meters can be reduced or avoided by ensuring air intake hose retaining clamps are loose enough to separate by hand. When a blow back occurs, the hose should be loose enough to allow separation from the airflow meter and/or throttle body and release pressure thus acting as a pressure relief valve protecting the airflow meter. If the retaining clamps are too tight, there is no pressure release if blowback occurs. This results in destruction of airflow meter.LOOSEN THESE RETAINING CLAMPS NOW!!

Sometimes the simplest ideas are overlooked! Our usual disclaimer applies – If you don’t immediately know what we’re talking about – please be safe, print a copy and take vehicle to a specialist.

Millenium Auto Gas on (UK)01256 766945 (telefax) can supply gas/petrol changeover safety relays and blowback release valves for self fit (around UK30.00). If you use this firm please email and let me know how you get on with them. But beware – We now have several reports that the blowback protection valves have failed to protect airflow meters including later hotwire types – PLEASE ENSURE HOSE CLAMPS ARE LOOSE EVEN WITH VALVE FITTED.

Feedback, comments and useful facts to rod@carelect.demon.co.uk

Air suspension problems

Disclaimer – please read

We have reports of air suspension problems and difficulties with diagnosing problems (or getting the suspension up) without the dealer HP notebook tools. It appears some owners are retro-fitting conventional coil spring suspension which may not be as costly or difficult as it seems at first sight – Anyone out there want to contribute a single page summary of procedures for me to publish?

A UK company, Scorpion Racing (London NW) can retro fit coils springs in one day for around UK600 plus VAT, or supply a DIY Kit for UK400 plus VAT. Contact Colin on 0207 485 5581 or email colin@scorpion-racing.co.uk If you have any comments on this service please email me.

As always we are looking into practical solutions and we hope this temporary page helps. Helpful practical observations on air suspension by David Burton can be viewed here. Mark Chandler has also sent in useful information on fooling the air suspension so it can be pumped up and the vehicle kept in use until the fault is rectified. Click here to view his email. Peter Barnes has also identified potential overinflation dangers from the a air suspension delay relay whilst carrying out these procedures, please click here to view his email.
PLEASE NOTE: DO NOT UNDERTAKE THESE PROCEDURES UNLESS YOU ARE SURE OF YOUR COMPETENCE. IF IN DOUBT, PLEASE BE SAFE, PRINT THESE PAGES AND TAKE VEHICLE TO SPECIALIST.

Problems seem to originate when a suspension component failure or maintenance work triggers an ECU fault code – It seems that any fault code will cause the system to vent and lower onto its buffers – ‘limp home’ mode, literally!! – Not helpful if you’re stuck in the bush hundreds of miles from a dealer.

Fault codes can apparently be triggered by such things as changing shock absorbers or alternator failure – FAULTS CAN TRIGGER WITH IGNITION SWITCHED OFF!! – so it may be necessary to disconnect battery before working on suspension.

If a fault code is triggered, the air suspension control buttons will be permanently lit (as opposed to lighting up and going out when engine is started) and the system cannot be restored until the fault code is reset by dealer HP notebook.

If a fault code is not triggered, but suspension will not pump up (and no leaks), problem could a seized compressor – try hitting compressor body with a SOFT hammer. This has a reasonable success rate but check fuses and electrical 1st!!

We also have one report of fault codes being triggered by defective battery earth cable/connection to body – the fault went away when cable renewed. Please email if this is your experience.

We understand fault codes survive ECU disconnection so it should be possible to airmail ECU to a dealer who can (using stock vehicle) read fault code(s), reset ECU and airmail it back to you together with any suspect part identified by fault code. If you’ve done this successfully please email.

Feedback, comments and useful facts to rod@carelect.demon.co.uk

Problems with the BeCM (Body Electrical Control Module)

There are many problems with the BeCM (Body Electrical Control Module) fitted to late model (from 1995) Range Rover and Discovery. Click here to see photographs of this unit.

The BeCM controls virtually EVERY electrical function on the vehicle and problems within the BeCM (or its associated fuse box) will cause mis-operation of vehicle electrical functions. When diagnosing electrical problems on vehicles fitted with BeCM, it is vital to appreciate the relationship between the BeCM and its associated electrical fuse box which is located in the engine compartment. The BeCM relies on this fuse box for nearly all its live feeds whilst the BeCM also controls the fuse box! ANY PROBLEMS WITH THIS FUSEBOX WILL LOOK LIKE BECM FAILURE! This fuse box suffers from internal corrosion problems probably due to its location which seem to manifest themselves at about 5 years (less in hot climates). Because it is almost impossible to diagnose faults caused by these fuseboxes we STRONGLY recommend that the fusebox is changed every 5 years or whenever there are vehicle electrical problems. This fusebox costs UK81.00 in UK and can be fitted in minutes. Please do not confuse this fusebox with the small fuse panel fitted to side of BeCM.

SYMPTOMS
1) SPECIFIC BeCM fault symptoms include mis-operation of headlights, door locks, electric windows, fuel filler flap, indicators, sun roof andespecially rear wash/wipe
. These faults may be intermittent.

2) Erroneous fuse failure codes are also symptoms of BeCM failure (if fusebox has been changed).

3) Intermittent engine non-crank can a BeCM failure symptom (if security system faults are eliminated)

DIAGNOSTIC CHECKLIST
1. Carefully check battery ground cable where it connects to vehicle body. If there is corrosion it is recommended to renew cable and thoroughly clean area before reconnecting new cable. Earth point check and clean should be part of diagnostic procedure whenever there are electrical/electronic problems.
With petrol engined models, we recommend upgrading to Range Rover diesel battery when renewing battery. It will fit existing battery tray and will help overcome erroneous fault codes (eg SRS) caused by low battery voltages when cranking or when heavy electrical loads are placed on system.

2. The BeCM fuse box located in the engine compartment should be second suspect. This fusebox suffers internal corrosion problems due to close proximity of engine coolant pipes resulting in microscopic (you can’t see it) engine coolant contamination. Whatever the cause, the fuse box is known to cause many different electrical problems and is a relatively low cost item (UK81.00) which is not specific to vehicle – it can be swapped out quickly and cheaply and may well save the costs of unnecessary BeCMs. WE RECOMMEND CHANGING THIS FUSE BOX EVERY 5 YEARS OR WHENEVER THERE ARE ELECTRICAL PROBLEMS.

3. Battery discharge problems due to mis-operation of the front screen heater can be due to faulty screen heater relays.

4. Low battery voltage due to defective battery cell can cause a wide range of electrical and electronic problems including setting the SRS light. Confirm battery voltage recovers rapidly to over 12.5V following short drain (eg run all electrical loads and accessories for 30 seconds with engine NOT running). Replace battery as above if any doubt.

We offer an excellent repair and reliability rebuild service for defective BECMs (Rebuilding is essential to maintaining reliability in the long term). This service has to be on an own unit rebuild basis because vehicle identity and security functions are programmed into the BECM during pre-sales dealer preparation – Rebuilding your own unit avoids programming costs! (hidden cost when you fit new BECM) If you would like a repair and reliabilityrebuild quotation please can you complete the quote request found below. Please skip questions obviously relating to engine management systems.

PLEASE NOTE: Because BECMs weigh 3 kilograms, our repair and rebuild service is currently restricted to UK and EU only.

 

CAUTION!

 

Odometer mileage readings are electronically stored in 2 locations on the vehicle – the instrument cluster AND the BECM. System programming ensures that in the event of any mismatch between the 2 locations, the odometer will permanently display the highest mileage!!! Merely switching on the ignition with another BECM (with higher recorded mileage) connected can cause the odometer to permanently display the higher mileage. The system CANNOT be changed back to the lower recorded mileage by reversing this procedure.

BeCMs are also matched to door lock codes. Please ensure (with dealer) lock set bar and EKA codes are written down before parting with your BeCM for exchange. If you can’t establish these codes, be ready to spend UK400.00 on a new lock set if you change the BeCM.

Components within the BeCM are CMOS technology which are extremely vulnerable to ESD (Electro Static Discharge) damage. Merely opening the BeCM can cause multiple component failures and result in the BeCM becoming unrepairable. Please, please resist the temptation to remove cover and poke around inside – it could cost you a new BeCM.

 

Full or partial loss of display and no response/incorrect response to fan speed dial

RANGE ROVER BODY HVAC DISPLAY ECU FAILURES

We now have a low cost rebuild service for this ECU

Symptoms

Symptoms are usually obvious! – full or partial loss of display and no response/incorrect response to fan speed dial.

Blowing hot air on very hot days is software fault in early versions of this ECU. I suspect that the software engineer did not ‘cap’ the temperature tables so above about 45C the software wraps around to lowest temperature in the table but email if you know better. Not much fun in Arizona. Fault can be alleviated by keeping vehicle internal temperature below threshold when parked – park in shade or cover sun exposed windows with alloy foil.

Diagnostic Checklist

1. Check ECU internal light bulbs have not failed especially if the display is completely blank. The light bulb for the display is a special only available from main dealers (but not expensive – 58pence! but watch out for main dealers 4 HOUR LABOUR CHARGE TO CHANGE THIS BULB!). A guide to changing this bulb can be found at http://www.rangie.com/rrkb/nf_articles/99.htm (thanks to Andy Cunningham for this info)

We have a low cost rebuild service for these ECUs. If you would like a quote please complete the quote request form you can find below. Skip questions relating to engine management systems.

 

Driver’s seat does not move but mirrors continue to work ok

The seat position memory ECU fitted to Range Rover Vogue between 1991 to 1995 is now failing with annoying regularity. Early symptoms of failure should not be ignored as this could lead to unrepairable faults developing. Be warned – this ECU is on long delivery lead times.

ECU is fitted under front RH seat and is a rectangular pressed alloy box about 17cm by 10cm by 4cm. It has a very distinctive grey ‘orange peel’ texture finish with cable looms coming out from 2 different sides. These cable looms terminate in 5 connectors.

Diagnostic Checklist

If both seat AND mirrors stop functioning without warning check for blown fuse or other electrical supply problems before condemning ECU. Don’t forget – seat only moves when park selected on gearbox!

We have a low cost rebuild service for this ECU – If you would like a quote please complete the quotation request form you can find below. Please skip questions obviously relating to engine management systems.

Mirrors no longer function but driver’s seat moves ok

The seat position memory ECU fitted to Range Rover Vogue between 1991 to 1995 is now failing with annoying regularity. Early symptoms of failure should not be ignored as this could lead to unrepairable faults developing. Be warned – this ECU is on long delivery lead times.

ECU is fitted under front RH seat and is a rectangular pressed alloy box about 17cm by 10cm by 4cm. It has a very distinctive grey ‘orange peel’ texture finish with cable looms coming out from 2 different sides. These cable looms terminate in 5 connectors.

Diagnostic Checklist

If both seat AND mirrors stop functioning without warning check for blown fuse or other electrical supply problems before condemning ECU. Don’t forget – seat only moves when park selected on gearbox!
We have a low cost rebuild service for this ECU – If you would like a quote please complete the quotation request form you can find below. Please skip questions obviously relating to engine management systems.

Driver’s seat moves to most rearwards position and does not respond to controls, or can move forward without warning and could trap driver with seatbelt.

The seat position memory ECU fitted to Range Rover Vogue between 1991 to 1995 is now failing with annoying regularity. Early symptoms of failure should not be ignored as this could lead to unrepairable faults developing. Be warned – this ECU is on long delivery lead times.

ECU is fitted under front RH seat and is a rectangular pressed alloy box about 17cm by 10cm by 4cm. It has a very distinctive grey ‘orange peel’ texture finish with cable looms coming out from 2 different sides. These cable looms terminate in 5 connectors.

Diagnostic Checklist

If both seat AND mirrors stop functioning without warning check for blown fuse or other electrical supply problems before condemning ECU. Don’t forget – seat only moves when park selected on gearbox!

We have a low cost rebuild service for this ECU – If you would like a quote please complete the quotation request form you can find from below. Please skip questions obviously relating to engine management systems.

Range Rover/Discovery technical sites

4×4 Web pages
Useful UK based 4by4 directory and 4by4 ISP