I need HELP! The problem began after a rebuild of the SC. Initially there was a very rough idle with a limit of the RPM to 3000. The error code at that time was misfires on multiple cylinders, the dash display read restricted performance. The issue has progressed to the point where the engine turns over, momentarily fires but will not stay running. Both fuel pumps run and have a fuel pressure of 45 psi, with the relays jumped, but the problem is not resolved. Both relays check out good, inertial switch was reset, battery good and battery ground is clean. ALL fuses have been checked. Battery voltage is present on both the primary and secondary side of the fuel pump relay sockets with the key on but apparently there is insufficient current to pull in the relays; the pumps will not operate with the relays in place. No OBD II codes present except in the case of the relays being jumped. Does this sound like primarily an ECM problem? Any thoughts are greatly appreciated.

 

Sorry to say I don’t have an answer for you beyond wild speculation.

I just have the same car as you (‘02 XKR) and know sooner or later I’ll have the same issues as every other ‘02 XKR owner.

Standing by to see what replies you get.


Z

 

The ECM was sent to ModuleExperts in Jacksonville, FL for interrogation/repair. The response was that the main processor was not functioning properly and could not be repaired because apparently it is integrated into the system. They offered a reman ECM, plug and play with a lifetime warranty for an additional $460 (already paid $254 to get the bad news).
I bought an ECM on EBay for the same year model but am waiting on an answer from a Jag dealer whether they will/can reprogram the used unit.

 

If it's the ECM, you can replace this relatively cheaply. If you already have a ECM that is suitable (Check your trunk under the carpet on the left side for which VCATS ECM you have, which you have likely already done).

Once you replace it, you just need to 'introduce it to the car' (Immobilization setup) with dealer-level software, not a reprogramming of the module. See #12 in the thread

https://www.jaguarforums.com/forum/x...cement-225633/

An independent mechanic local to you can probably do this for you. About a 15 minute job.

All that said, if the problem started with a SC rebuild, perhaps that's a more likely source of your issues.

Note: When I needed a new ECM, the most local dealer would not do the Immo setup for me for my $40 ECM and wanted 4K for a new ECM. The local independent was happy to do it, but after 8 weeks of waiting for them to fit me in, I bought IDS and did it myself. So, it's relatively straightforward and quick.

 

It is possible, but IMO unlikely, that the ECM coincidentally died during the supercharger work.
Post-97 ECM failures are rare (at least, I've not read of one).

However, if the numbers on the ECM you have bought match that on the car's VCATS label, it would be worth swopping it in to eliminate ECM failure:- I wouldn't expect any programming to be necessary?

As you have likely found out, replacement used ECMs can be had for much less than $460!


Generally, if something seemingly unconnected breaks after work has been done, then revisit the work done. Could the disturbed engine harness wiring and connectors have a problem?

Bear in mind that in normal operation, the fuel pump only operates for around 2 seconds or so after the key is turned, until the motor starts.

 

I thought perhaps I had pinched wires when installing the SC, so I went back and removed the SC etc. and found nothing afoul before sending the ECM off.
The primary issue was the engine would fire momentarily but would not stay cranked. There was no fuel pressure when trying to start the engine. The signals to the terminals for the fuel pumps had voltage but insufficient current to pull in the relays. I was able to get 45 psi with the relays jumped and both pumps were operational but even in the jumped state, there was no start. This is what led to the conclusion the problem was a malfunction of the ECM. The ultimate cause of the ECM failure is a guess.

 

I think this is correct on ECM robustness. The programming part is certainly true, only the immobilization setup is necessary.

I only replaced mine because it was much cheaper and less fraught with potential error to substitute a 2002 ECM for my 2001 rather than flashing the ECM to the 2002 and later version so that the new design EVAP valve would work. The 2001 EVAP design is no longer available new when the old one breaks, as it did. On the other hand, plenty of 2002 ECMs around.

 

If any vacuum lines were disturbed they would be my suspects.

An air leak can easily stop an engine running and if it happens early on there's little chance to flag a code (though misfires might be - hinting at lean e.g. too much air).

 

Update on the ‘02 XKR: the ECM was found to have a fault in the main processor, which was irreparable and a used identical unit was installed, scanned and all fault codes removed. The unit was recoded for the current key and the engine started and ran as it should with no fault codes appearing. However, after turning the engine off, it would not restart, only spinning over and the key fob would not operate the door locks. Multiple attempts to reprogram the key fob were unsuccessful.
The next step is to replace the SCLM and see if this resolves the issues. Any thoughts about the KTM being the root of the problems?

 

All of this is started after the supercharger R&R, and you now have different symptoms after the ECM swop.

If the car is cranking, then the key security is fine. The fobs not working is a separate issue - it may be related to the SLCM, but that module is only responsible for the car's perimeter security (doors, hood, trunk lid, etc.). A malfunction won't affect the ability to start the car.

I would not change any other modules for the moment as you risk introducing more problems.

 

Finally got the original ECM back from ModuleExperts (supposedly irreparable due to a fault in the main processor, reman unit available for an additional $460). Plugged it in with the original SCLM and the engine fired up without hesitation. The engine repeatedly fired up both hot and cold and ran smoothly with no fault codes or issues (Launch v431+Pro). Hopefully the Majical Mystery Tour is over but I’m not ready to give a sigh of relief just yet.
Reprogramming the key fob was unsuccessful in the ignition II position but did reprogram in the I position.