Hello All,

Can anybody advise where I could pick up a replacement ECU for a manual XJ6 (x300) 4.0L Sport, 1996 Plate?

I have had numerous problems with the car cutting out during running, and have replaced starting coils, the air flow meter, TDC sensor and cooling water temperature sensor. When attached to the diagnostics computer the fault code is showing for damaged ECU.

From reading through the forum and posts I see that this is a typical fault with the model, and from searching on E-bay it would appear a number of ECU's are available for the automatic transmission configuration, but I've yet to see any advertised for the manual version.

Any help would be appreciated, I'm on the verge of moving this car on which would be a minor tragedy as it is in good condition otherwise.
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Martin Mackenzie
XJ6 Owner, 1996 4.0L Sport, X300

 

Have you done a reset of the ECM? GEMS 6 can learn some really bad habits due to worn parts, and sometimes you have to make it unlearn the bad habits after the mechanical problems are addressed.

If the ECM turns out to be the problem, I would investigate whether there is a difference between an ECU for automatic car and manual one, other than the PROM chips. I suspect that the ECU is the same, just the chips are different. I would confirm that with a knowledgeable ECM rebuilder. If this is indeed the case, you can buy an ECM and swap the chips. In any event, you will need to reset the ECM after the swap.

 

Thanks Juha,

Do you have any instructions on how to reset the ECM?

All the best,

Martin

 

Sadly resetting the ECM requires a special tool and software (IDS, WDS or PDU). A competent Jaguar shop should have requisite equipment available.

 

In my experience faulty engine ECUs are extremely rare, unless it has suffered water ingress into the main harness connector, which you can check by removing the ECU. If it looks OK then it probably is OK. What is the fault code that makes you think the ECU is faulty. It is much more likely to be a sensor or actuator failure. There are plenty of them that do go wrong. Manual 4.0L cars are exceptionally rare, so you are unlikely to find a direct replacement ECU. However, as suggested elsewhere you can take the EPROMs from one ECU and fit them to another. I can provide this service if you contact me directly. The resulting ECU will still have to have the throttle adaption reset set and the lambda sensor orientation performed which require sophisticated diagnostic equipment that only Jaguar main dealers or specialist independent Jaguar dealer will have.

 

Hello XJR Engineer,

The problem has been traced back to when the front windscreen was replaced, it looks as if the ECU has suffered from water ingress due to a poor seal or when the windscreen was being changed.

Thank you for your input.

Martin

 

I have a spare ECU just got ome from a week away I will look tomorrow at the P/N on it and post it up

 

Excellent, many thanks