Last Sept., on a hot Friday afternoon, my 2004 XJ8 (with only 22,300 miles) displayed "Restricted Performance" on the dash and the engine promptly quit. After risking my life getting to the shoulder, it restarted but ran very rough and then quit again and wouldn't start. Towed to the dealer who didn't get to it until after the weekend and which time it started and ran for them. They told me there were several codes thrown and it indicated a bad relay box and fuel control module which they wanted to replace. Since they couldn't tell me for sure that these components were actually "bad", I had only the FCM replaced. 10 miles after leaving the dealer the car did the same thing to me. Back to the dealer and replaced the relay box....total for both sensors: $2600. Within 100 miles the car repeated the failure. Back to the dealer. NO CODES WERE THROWN. By the time they got to the car it started and ran. After test driving for over 50 miles it finally quit on the technician (again with no codes thrown) who then said it was a bad fuel pump. Indeed after 400 miles with the new pump I've had no problems.

My theory is that the fuel pump was the culprit all along, and due to the inability of the dealer to effectively troubleshoot, I'm out $2600 for two sensors that didn't need replacing.

I'm currently trying to get some money back from the dealer. They're claiming a "high resistance" in the fuel pump could have "taken out" the other two sensors. Sounds suspiciously like an excuse to me. I'm considering writing to Jaguar US corporate headquarters.

 

I would have "high resistance" to not being given a convincing explanation for the repair strategy.

It could turn out in the end that these are sequential faults and not a misdiagnosis of a faulty pump in the first instance but being told there were "several codes thrown" would not satisfy me.

If the dealer is unable to provide details of the original codes and why they decided the cause was a bad relay box and fuel control module rather than a fuel pump, then a complaint to Jaguar CRC is the obvious next step.

Graham

 

Yes, without knowing what the trouble codes were...and some other details....
it's very hard to say if the course of action taken by the dealer was, or wasn't, appropriate.

Presumably the parts they replaced (including the pump itself) can be individually tested before being condemned....but, naturally, all the testing in the world is unlikely to be conclusive unless the testing is done when the component in question is *actually in failure mode*. This is why solving intermittant problems is difficult.

From what you've written it sounds like the dealer couldn't confirm any failures with the relay or the module and they were guesswork replacements. Now, as guesswork goes, there are good guesses based on the evidence at hand and/or prior experience....or there are totally dumb, blind guesses that make no sense at all. I don't know enough about your model to comment on how good or dumb the guesses might have been.

How were the first two attempts presented to you? This is important. Did they say something like "We've found the problem. You have a dead FCM. It'll be $xxxx to replace and you'll be good to go. Would you like us to proceed?" ?

Or did they say something like "We're unable to positively confirm any failures. The trouble codes suggest a fault with the FCM, and we've have seen similar failures of FCMs in the past. Replacing the FCM might do the trick. It'll be $xxxx. Would you like us to proceed?" ?

The difference between the two is obvious. The former puts the onus on them; the latter puts the onus on you.

Assuming the latter scenario....them admitting they didn't have a concrete diagnosis...there was always the option to do nothing until a postive diagnosis *could* be made. Heck, two days ago I was at the doctor for a problem where the battery of tests 'suggested' xxx-condition. Several courses of action were spelled out, inlcuding 'wait for further developments'....which is what I plan to do!

As for contacting Jaguar at the corporate level ....well.... don't get your hopes up too high. They'll probably consider this to be a private dispute.

I'm not unsympathetic to your situation. I'm just trying to add some perspective.

Cheers
DD

 

You are pretty much at the mercy of the Dealer on this one. If he had tested the rear electronics module (REM) and fuel relay, he would have pinpointed the failure. Since you can't prove anything, he can always say that the pump overheated the module and relay. The REM powers the fuel pump and is fed power by the pump relay. They are all connected to the pump drive circuit. If I hqad to guess, you are right, the pump was bad all along and teh other two thigns were probably fine. If they gave you the old parts (and they should have) you could get them tested to see if they were really bad. All you would have to do is to reinstall them and see if the problem reoccurs.

 

Would the REM and/or relay test 'bad' if the engine was starting and operating normally?



Is the typical fault mode of these parts always a hard failure? Or can they intermittently fail?




That would be the best bet, yes!

Cheers
DD

 

More details:
1) When the engine conked out the first time, the following codes were found: P022, P0122, P1235, P1338 and P0783. Dealer asked to replace throttle body sensor, REM and Fuse box. I declined and took the car after they reset the codes.
2) Ten miles later, car conked out again. Towed back to dealer. Codes P1235 and P1338 appeared again. Replaced rear electronic control module.
3) 50 miles later conked out again. Towed back to dealer. No codes thrown. Replaced fuse box and tested it for 70 miles without a failure.
4) 290 miles later conked out again. Towed to dealer on late Friday. Started for the dealer the following Monday. Driven for 70 miles before the dealer saw the problem. Traced it to the fuel pump.

Interestingly, no codes were thrown those last two times.

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