Hello to everybody,

I own a 2000 Jaguar XJR which suffered from a failed knock sensor on bank A. One morning without warning the yellow engine MIL went on and "restricted performance" was displayed.
I replaced both knock sensors and all gaskets, o-rings, seals and some hoses that I came along.

When I started the engine after doing the repair, my obd scan-tool still shows a P0376 error. This DTC already had been there when I diagnosed the failed knock sensor (DTC P0324, P0328, P0329, P1314, P0376). At that time I thought that's related to the failed knock sensor.

I went through all DTC documentation from Jaguar and tried to look up the meaning of P0376 but I can't find any information!
The yellow engine MIL still comes on, the display still shows "restricted performance" and the engine still runs quite rough (I think because of the "restricted performance" mode). However the DTC for knock sensor failure on bank A disappeared after replacing it/them and didn't come back since then.

Now, when I reset the DTC codes while idling the engine almost immediately falls back in "restricted performance" mode + yellow engine MIL and the first DTC which appears is P0376. After 1-2 minutes idling DTC P1314 and P0324 pop up as well.

Can you help me with this issue? Since I can't interpret P0376 I have no clue what to look for.

Best regards,
Alexander

 

Attached is the results of a quick online search of the code P0376. According to the info it is generic to all cars, but i did also find it on the Jaguar DTC lists.
It would appear that one of the position sensors is not working correctly. My guess would be crank position sensor and cam position sensor.
Hope it helps and let us know what you find.

 

Hi avern1,

thanks for the attachment. Mind you to tell me, where you found the DTC in Jaguars DTC list? Because most of Jag's DTC lists also provide monitoring conditions, default actions and possible causes.
And since my Jaguar DTC lists do not provide any information about P0376, I'd really appreciate to have a more updated version :-)

I was thinking in the same direction as you, but since I got no other DTCs flagged concerning the crankshaft position (CKP) or camshaft position (CMP) sensor, I dismissed that. My thinking was that if the CKP and/or CMP sensor is failing, there would pop up DTCs like P0335, P0340 or P1336? Am I wrong with that?

Since the sensors are not cheap to get, I'd like to avoid spending loads of money without having clearly identified the CMP/CKP sensor as root cause for my problem.

Best regards,

Alexander

 

Hi to everybody,

since I'm still at a loss concerning the "restricted performance" mode of my car, I'll try the following at the weekend:

1. inspecting the secondary tensioners of LH and RH bank and checking, if the timing is still right
2. disconnect the camshaft position sensor(s) and crankshaft position sensors and check which DTCs will pop up
3. ECM hardreset/adaption according to TSB 303-01

Hopefully with this I'll get a better idea of what's wrong with the car :-)


Question: According to JEPC there had been one camshaft sensor until VIN 853935 and from then on two sensors? So my MY2000 XJR got two camshaft position sensors to look for?
EDIT: Looking through the electrical guide for MY2000 XJs I found out, that there are indeed two camshaft position sensors...one on each bank.

Thanks for your help...I'll keep you updated :-)

 

It would be interesting to know if the AJ27 engine for the XJR actually has two sensors. The two sensors happened in order to control the proportional VVT, which the XJR does not have. No doubt they keep the same sensor list in order to not have too may variants in the control scheme.

 

Hi sparkenzap,

Attached you can find a screenshot from the electrical guide MY2000 XJR and you can find two CMPS. When I googled the sensors I recognized the connectors. When disassembling the air intake system, I disconnected two of these connectors...one on each side.
Best regards, Alexander

 

Hi all,
last weekend I did some testing as mentioned before (even if I didn't do everything coz I had just little time).
The camshaft position sensor is ruled out - when disconnected it throws different DTCs.
Then I removed all ignition coils and found some oil in the spark plug recesses of cylinder 4A and 3B (approx. one teaspoon). The corresponding coils were good, just little oily outside the rubber boot.
All other coils were in an excellent shape (no damage, no cracks, no oil on the bosses, no rust) as well. Then, I inspected the plugs..no abnormalities so far (they are quite new, just 30k km ~ 18.6k mi on the clock). After that, I swapped the bank B coils to bank A (coil 1B for 1A, 2B for 2A and so on) and as a result, DTC P0376 disappeared and a new DTC P0364 popped up. To narrow down which coil is the culprit, I exchanged the coils back one after another, starting with 1A for 1B and read the codes after each swap. P0364 remained till I finally swapped back 4A for 4B and P0376 reappeared! Great, I thougt!

To isolate the culprit coil with certainty I swapped the supposed failing coil 4B for 1A and awaited DTC P0364 to pop up again. Unfortunately it didn't and DTC P0376 remained!
After that I swapped the coils all around the cylinders and banks, but without getting a pattern when P0364 or P0376 is set!

Just today I googled which plugs I got in my car: The garage shop which did the service when I bought the car last year used NGK IFR5N10 plugs. But NKG recommends them only to be used for cars from MY2002 on. I'm quite unsure, if that's causing my problem, since they went well for the last 30k km.

Any ideas on that?
My assumptions so far: some weak coils on their way out, but not weak enough to cause a misfiring (still no misfiring DTC, only P0376 or P0364)?
AND/OR
The ECU is on it's way out?
OR
The combination of "wrong" plugs with weakening coils went bad when the knock sensor failed too?

So what to do next?
My ideas for next time I get to my car:
- Doing the JTIS pinpoint testing for the coils (resistance, voltage etc)
- inspecting the ECU visually for any damage (blasted capacitors etc)

Best regards and thanks for your help!
Alexander

 

I think it might be timing on the left bank, #6. It is pulsing too early or too late.

What is the status of the 2nd tensioners?

 

Hi Jim,

thanks for your input. Hadn't had the time to pull the valve cover so far.

Moreover I would expect DTCs like misfiring or something like that in case the secondary chain skipped a tooth and not DTC P0376 to disappear, when swapping the coils.
Either way you're dead right that I should check them. I'lll do that as soon as possible since I have to replace some spark plug seals anyway.

Best regards, Alexander

 

I would look in your owners manual and replace the plugs with what's supposed to be in your engine. Also make sure they are gapped properly. I know some people will say no to gapping an iridium plug, but I've done countless sets of iridium plugs over the years and always gapped them per the manufactures specifications without any issues. I would do a hard reset as my next plan of attack along with the plugs. You might be right about a failing coil though.

 

This seems to be the only report of any Jaguar with P0376. Congrats?

Because the tensioners are such a huge risk I'd be checking them first.

I would not check the gap on more than one iridium plug as they come pre-gapped and are staggeringly easy to damage. How 8 of the wrong plugs could cause one weird code only ... well, strikes me as unlikely. The main idea of the plugs is that they last longer (and cost more!).

I really don't see this fault being plug-related. But... as it's a unique fault, can't rule it out.

A coil? Could be. Or its wiring/etc.

The PCM? They're almost but not quite bulletproof, so eventually it's a suspect.

On the S-Type the PCM has sometimes (rarely) been found to be wet - don't know if this can affect the XJ, sorry.

Sorry to ramble, maybe it helps. What would I do? After checking tensioners & timing, I'd get an extra coil and swap it in turn to see if the fault would go. Next if the PCM might be wet I'd check that but they can be awkward to access. I'd leave the plugs in until I'd checked everything else. That said, it may be that the plugs need a different coil (the kind my car has, sorry don't know what the XJR has but I suspect an earlier, different, type) so I suppose it could be a plug-caused problem.

 

Dear all,

First off, thanks for your posts and for obviously having the only x308 with p0376/p0364
Today, I tested the following:

1. JTIS pinpoint test (see attachment) for wiring, relay and spark plugs
2. visual inspection of engine management module (ECM)
3. removal of valve covers and inspection of timing gear

Results:

1. The wiring is great! All within their specifications - no shorts, no open circuits, no high resistances. Except of pinpoint test B "spark plug resistance". Since the park plugs are iridiums (see #7), they got different resistance than stated in JTIS.
2. No damage on the circuit board, no blasted capacitors or anything conspicuous. Was never been opened before, seals had been still at it.
3. Timing is good! Wheeee!!!! The machined flats are aligned pretty accurate - on both banks. Even though I still got the plastic tensioners as secondaries.

BUT it's quite a mystery why the previous owner fitted 3rd gen primary tensioners (metal), but didn't replaced the secondaries too?! Or am I wrong? When I had a quick glance alongside the primary chain the tensioners seem to be made of metal? What's your opinion on that (see pictures)?

In summary I didn't come closer to the problem. After replacing the secondary tensioners and renewing the gaskets and seals of the valve covers, I will go with replacing the sparks for the recommended platinum tipped sparks (NGK PFR5G-11E). Hopefully that will solve DTC p0376/p0364. If not, I'm having to replace the coils

But it still leaves the question open why the sparks went well until the knock sensor failed. I definitely hadn't any engine MIL before :-(

Fingers crossed for the sparks as culprits!

 

Dear all,

My big green cat is truly putting my patience to the test
Meanwhile I replaced the secondary tensioners and the spark plugs but that didin’t cure the „restricted performance mode“.
What I did and replaced so far:

• Knock sensors (both banks)
• gaskets, seals and o-rings of air intake system (e.g. supercharger outlet duct seal, coolant outlet duct seals, intake elbow gasket, EGR valve gaskets, throttle body gasket, heater hoses, intake gaskets [injectors – cylinder block and air charge coolers – injectors])
• valve cover seals (both banks)
• secondary tensioners (both banks)
• spark plugs (PFR5G-11E)

Replacing the knock sensors cured the P0328 and P0329 codes (as mentioned before). But P0376 and P1314 didn’t go away.
And still the car enters „restricted performance mode“ and is running rough. When starting it starts immediately and does not show any starting problems like stumbling etc – it starts right with the first crank.
The following root causes can be ruled out so far:

• bad timing (checked when replacing the tensioners)
• knock sensors incl. wiring (pinpoint tested – see JTIS)
• cam shaft sensors
• wiring for ignition coils (pinpoint tested – see JTIS)
• spark plugs
• weak battery

What I observe right now:

• turning over the car (with fuel delivery disabled and spark plugs out) is smooth and easy, no clicking or knocking from the valves
• the car is starting immediately without problems
• when letting the car idling for 2-4 minutes I obtain three DTC which are saved: P0328, P0376, P1314 and „restricted performance“ right from the start
• when swapping the coils from bank B to bank A and vice versa I obtain no saved codes, but P0316, P0364 and P1314 as intermittent/sporadic fault and „restricted performance“ right from the start
• no water in oil system, no excessive white smoke from the exhaust, no oil in coolant
• hard reset doen not have any effect

I’m desperately lost on that issue. Any advice on what to do next or what to test for tracking down the issue?
I don’t want to burn my money on replacing the coils if I’m not sure if they are the culprits.

Thank you very very much for your help!

 

The next step I would take is inspecting the contact points inside the relays that are next to the ECU's. They are known to go bad also. I've taken them apart and as long as the contact points aren't completely burnt up, you can use a small flat head screw driver to clean the surfaces up. Check the power lead cable connections while you are at the relay area of the ECU's. They get loose and have also known to cause issues. If that didn't help, then is go checking the ground wire from the bottom of the engine to the underside of the floor pan.

 

I suggest going back to the code changes after the coil swap. See if it is repeatable after swapping back and forth several times- That would not be my first plan, but since it is really all of the data you have right now, make sure it is meaningful.

Also, remember that many RP reports (often without codes) come from the throttle body connectors. Many times in diagnosing problems, when two or more faults exist, they cloud the diagnostic procedure. I suspect you might be experiencing that phenomena.

 

Thanks to all for the advice! I'll check the ground cables as soon as I get back to the car.
@sparkenzap: What do you mean with "connectors are clouding the diagnostic procedure"? How can I track down if that's the case? Just clean them and spray with contact spray?

Best regards, Alexander

 

Sorry; I confused you with the pronoun "they" which was meant to have the antecedent "multiple faults", not "connectors"- or something like that- I am not an English student!

Anyway, it is multiple root causes that cloud the diagnostics, so I was suggesting looking for other faults that could cause the same symptoms. The connector pins on the throttle body connectors are known to cause RP without good diagnostic codes. So I was suggesting a good cleaning and examination for them.

 

Hi to all,
Got still a finger on the issue, but I didn't had time yet for testing the (ground) connections. I gathered two used ignition coils which are known to be good, too. So I'll swap them around and see if things will change. I'm planning to get to the car the upcoming weekend - I'll keep you up-to-date.
Cheers, Alexander

 

Dear all!
Good news! The cat is growling again!
When I swapped around the two used ignition coils which I bought several days ago, I identified one weak coil on bank A! Obviously not weak enough to cause any severe misfiring (had no codes), but weak enough for not having a strong spark. Finally all DTCs are gone and the big green cat is running fine.

Unfortunately the connector plug of the transmission started leaking, so I had to replace that too.
But for now everything is fine :-) I feel truly relieved!

In follow-up to the repairs I have to have the front wheels adjusted since I replaced the LH wheel bearing during the downtime. And I have to sort out why the klicking noise when indicating has gone - any ideas on that? The car doesn't even make the "bling" sound when saving the settings of the mirror, steering wheel and seat positions. Maybe just a blown fuse?

Thank you all very much for your support during troubleshooting my issues :-)

Cheers,
Alexander