I recently traced an intermittent engine shut down that turned into a no start at all issue to my 1995 XJ6's ECM. I was able to procure one from a similar car to prove my theory. The car fired right up but idles fast (2000 RPM in park). Now, with the problem diagnosed, it is time to affect a more permanent repair.
The original ECM: 4.0L N/A LNA 1410 AH with a sticker on the back that says R493 LNA 1410 AL then the hand written date of 10/31/2002.
The replacement ECM: 4.0L N/A LNA 1410 FC with a sticker on the back that says R493 LNA 1410 FE then the hand written date of 2/27/2002

-Is there someone that rebuilds ECMs?

-Am I looking for a used replacement with the same suffix as the original sticker (AH) or the same as the 2002 number (AL)? Do these second stickers and numbers represent a recall?

-Will other ECMs work as long as the first Letter in the suffix is "A" or should I look for the specific number listed on the 2002 update?

Thanks in advance.

 

Please keep us informed. A lot of us have shut downs.

 

I think the AL indicates that your ECU is a replacement that has been reprogrammed with dealer software, and that is what you should look for. From what I have read on the V8 forums, later models like the FC may work, but maybe require a refresh by dealer software. This is a complicated subject, and I probably shouldn't even be offering an opinion.

 

No personal experience but ASI gets high marks from others in the XK8 section.

Automotive Scientific Inc. Your #1 Source for ECU, TCU, ABS, EBCM, Climate Control and Speedometer Repairs

 

You just need to get a throttle adaptation performed by a Jag independent on your replacement ECU in order to get the idle speed control working.

 

There was a RECALL (T493 and R493) back in the early 2000s (Hence the handwritten dates on your ECM). We swapped EPROMS, throttle springs and EGR valves. I did DOZENS and DOZENS of these repairs.

You will need to perform a TPS adaptation as previously mentioned but ALSO an Oxygen Sensor Orientation if the ECMs are swapped or the EPROMS replaced.

You need to read the TSB attached for info.

You could have tried to swap EPROMS from your old ECM if the fault was NOT from the EPROM to MAYBE retain the original TPS and O2 orientation but once you swap them, BOTH ECMs need to be configured to each car.

A few months ago I swapped my 1997 X300 LWB ECM to another X300 for diagnosis for another car repair shop.

The ECM turned out not to be the problem but I had to re-orient the ECMs back to EACH car with my WDS!!!!

bob gauff

 

I removed mine to check the connectors and there was a "warranty void if removed" label from (linky) Autocomp Technologies

 

Bob, thanks for the experienced information. I suspected a recall due to the large number of 2000 revision dates on the units (I didn't think everyone’s ECM could fail at the same time).
I have ordered another used ECM this time with the "AL" suffix. And it should arrive in the next day or so and hopefully get me back up and running properly. I will let the forum know the results, however perhaps you can answer some questions that I am curious about and therefore may help future readers.

Is this EPROMS a plug and play portion of the ECM circuit board or is it a soldered in place item? (exactly how easy are they to change?) I returned the tool I borrowed to open up my ECM or I would check myself.

Is the EPROMS the only difference between the various "-AL", "-FC" and other model ECMs with the LNA 1410 prefix?

Can someone capable of reprogramming a ECU change a "-AL" unit to a "-FC" unit or are there other fundamental differences between them?

Are replacement ECMs with the same reworked part number interchangeable or does recalibration have to take place no matter what? Again with the -FC version my car now starts and runs, but with an over enthusiastic idle speed and the Trac Control & ABS failure lights lit. I am not sure that the latter is related to the ECM or if all the fiddling I did trying to diagnose the problem left something loose.

 

The suffix in the part number determines the software level and calibration. If you swap the socketed EPROM between ECUs, then you are effectively changing the part number suffix.


Two ECU with the same part number suffix are interchangeable. However, an ECU removed from one car may need a throttle adaption and lambda sensor orientation performed before it will work correct on a different car.

 

Thanks again for all the help and information. I purchased a used ECM with the proper suffix and the car is back to its good old self. The Trac fail and ABS lights went out after about 60 miles of driving. I guess the ECM just needed to adapt to the car. All is good now or at least as good as it can be with a 19 year old machine. On to the little incidentals that I found while doing the ECM diagnosis - Rochester valve is #1.

 

The ABS/Trac fail light is not controlled by the engine ECU. I common cause of this light coming on, is a dry joint in the power feed to the ABS pump. This joint is in the ABS ECU.