I will give this a try and report back this morning. Thanks

 

Hi,
OK - if it briefly runs smoothly then likely most, if not all, cylinders are initially firing until the ECM shuts them off (a P035x code action) due to missing spark feedback.

I keep this pic. handy as I can never remember which cylinder is which

 

Michael,
Before receiving your suggestion for the "simplest check", I had started doing what Y2KJag recommended and switched cylinder 1's coil on cylinider5. I didn't detect any difference in how the engine started and idled. I left those coil modules as they were when I read and decided to abandon that and do your test.I hope I did all this correctly,.,. Here is what I have done:
I unplugged coil modules for B1, A2, A3 & B4 one at a time. After each unplugged. I started the engine and I noticed the biggest difference in how the engine idled/ran when I unplugged A2 as there was a distinctly rougher idle initially when it was unplugged versus when the others were unplugged, the initial idle was smoother initially and then clearly changed to rough. I unplugged A2 again after running the test on all 4 to make sure I was correct in how the idle was different.
After doing this testing, I checked the OBD2 codes. This is what displayed: P0308, P1316, P0352, P053, P055, P058, P0352, P1000.
If i failed to do this correctly, please advise.
I am not sure that I understand how these codes relate to a diagnosis. Also, if the coil module for A2 being unplugged points to that module as being my problem, should I switch modules to see if it is truly the coil versus something else?
I hate being so ignorant so if you have a reference source for me to understand what is going on I am all ears.
Thanks!

 

Hi,
belated response as I've been away in the Netherlands for a long weekend.

Hi,
If it made no difference and didn't change the P1368 then no harm leaving them where they are.

Ignore the P1000 for now as that's just flagging that the emissions monitoring tests haven't completed. Similarly, you can ignore the P0308 (misfire on B4) & P1316 (excess emissions) as I suspect they're linked.
What you describe sounds fine; your checking hasn't pointed to a coil module causing a problem itself or with the others. You could try swopping the A2 across with B2, but I suspect it will make no difference.

The car is telling you what it thinks is wrong as a guide to where to look.

When everything is working properly, the ECM will send a ‘coil fire’ instruction to each ignition coil module at the correct point in the relevant cylinder’s cycle. If the module successfully creates a spark, it will send a ‘spark OK’ confirmation pulse back to the ECM. All is good, and on to the next cylinder.

However, if the ECM doesn't see that confirmation pulse, it will throw a P035x code. For example: P0351 “Ignition coil (A1) primary /secondary circuit malfunction” In your case, the ECM is also telling you (P1368) that it's missing the confirmation pulses for the whole cylinder group. I've included P0351 as that entry contains the default action & possible causes for the P035x codes


My interpretation of the 'monitoring conditions' is that the ECM will allow a period of time (~5) seconds for the motor to settle down after start before it acts on any abnormal input(s), hence the brief period of smooth running after startup.

The ECM will then take the default actions stated for a P035x code. Note default actions include:

• Inhibit closed loop for the bank
• Inhibit individual cylinder fuel injection - effectively shutting down the affected cylinder so raw fuel doesn't get dumped into the exhaust.

So, from the codes, then:

1. No ‘coil fire’ command is reaching the ignition coil module
2. There is no confirmation pulse being generated by the affected cylinders
3. The ECM isn’t seeing the confirmation pulse
4. The ECM isn’t responding correctly

What we're trying to do is narrow down the car's diagnosis to the faulty component(s)
1) we can discount as you have a period of smooth running
2) unlikely to have four coil modules fail at the same time
3) Possibly. Could be a short / open circuit in the engine wiring loom stopping confirmation pulses getting back to the ECM.
4) Possibly.

My references are mostly drawn from a combination of the Electrical Guide and the DTC list. The Jaguar training manual 881 is also useful. From Gus' site:
http://www.jagrepair.com/images/Trai...ual-9-5-01.pdf

 

[QUOTE=michaelh;2676597]Hi,
belated response as I've been away in the Netherlands for a long weekend.



Hi,
If it made no difference and didn't change the P1368 then no harm leaving them where they are.



Ignore the P1000 for now as that's just flagging that the emissions monitoring tests haven't completed. Similarly, you can ignore the P0308 (misfire on B4) & P1316 (excess emissions) as I suspect they're linked.
What you describe sounds fine; your checking hasn't pointed to a coil module causing a problem itself or with the others. You could try swopping the A2 across with B2, but I suspect it will make no difference.


The car is telling you what it thinks is wrong as a guide to where to look.

When everything is working properly, the ECM will send a ‘coil fire’ instruction to each ignition coil module at the correct point in the relevant cylinder’s cycle. If the module successfully creates a spark, it will send a ‘spark OK’ confirmation pulse back to the ECM. All is good, and on to the next cylinder.

However, if the ECM doesn't see that confirmation pulse, it will throw a P035x code. For example: P0351 “Ignition coil (A1) primary /secondary circuit malfunction” In your case, the ECM is also telling you (P1368) that it's missing the confirmation pulses for the whole cylinder group. I've included P0351 as that entry contains the default action & possible causes for the P035x codes


My interpretation of the 'monitoring conditions' is that the ECM will allow a period of time (~5) seconds for the motor to settle down after start before it acts on any abnormal input(s), hence the brief period of smooth running after startup.

The ECM will then take the default actions stated for a P035x code. Note default actions include:

• Inhibit closed loop for the bank
• Inhibit individual cylinder fuel injection - effectively shutting down the affected cylinder so raw fuel doesn't get dumped into the exhaust.

So, from the codes, then:

1. No ‘coil fire’ command is reaching the ignition coil module
2. There is no confirmation pulse being generated by the affected cylinders
3. The ECM isn’t seeing the confirmation pulse
4. The ECM isn’t responding correctly

What we're trying to do is narrow down the car's diagnosis to the faulty component(s)
1) we can discount as you have a period of smooth running
2) unlikely to have four coil modules fail at the same time
3) Possibly. Could be a short / open circuit in the engine wiring loom stopping confirmation pulses getting back to the ECM.

How would I eliminate a short or open circuit in the engine wiring loom as the cause? Can I use a multimeter to test and confirm continuity? If so, is there a wiring diagram I can use to identify the wires of each circuit needing to be tested? Or a diagnostic tool to test this?

4) Possibly.
I had the ECM tested by this company out of Texas which returned it as fully functional. I am not opposed to sending it out for another opinion if anyone has a recommendation.

Ari Luna
GoECM Shipping/Receiving Phone: 972-602-8100
Fax: 972-854-5318
Direct Line: 817-541-0430
2610 W Marshall Drive
Grand Prairie, TX 75051

 

Yes, you can certainly use a multimeter to test for continuity, and for shorts to anywhere. Download the 2000 Electrical Guide from member Gus' site here:
http://www.jagrepair.com/images/Auto.../jagxk2000.pdf

which will show you the wiring and colours - see Fig. 4.3. There are some pinpoint checks that may help you in the Workshop Second Edition (available from the 'stickies' at the top of the page).
In addition to the multimeter, my diagnostic tool of choice for this would be an oscilloscope:- particularly since there is a functioning cylinder group to compare with - but I appreciate most people won't have access to one.

This is conjecture on my part, but IMO it is very unlikely that a generic ECU repair shop would have access to the diagnostic jigs, tools and proprietary information to test a module to this depth. I suspect only the OEM (Denso) will have the capability.
The only sure-fire way to test would be to substitute your ECM into a known working vehicle and see how it performs.
Q.E.D.

 

Michael and anyone following this thread,
I found a video by a 10+ year owner of several XK8 models who contends that all difficult diagnostic challenges can be avoided by renewing the coil packs on the car as they don’t last… see you tube video here: I am still unable to find my issue….after spending a considerable amount of time studying the wiring diagrams, I don’t think I will be able to identify and properly test the ecu to engine wiring that might be involved.
I took the car out for a run yesterday and I experienced a very rough running engine for about the first 3 minutes or 10 blocks and then it totally changed…smoothed out and was so responsive and fun to drive again for about 5 minutes before slipping back into restricted performance mode 😩.
I checked the codes to find the following: “current”: P0308, P1314, P0353,55&58. “Pending” : P0308, P1316, P0352,53,55&58. Also, I noted the absence of P1368.
The coil packs which are currently fitted were replaced by a non-jaguar shop during ownership of PO in November 2019 at 77,933 miles (that was 5,400 miles and nearly 4 years ago). I have the invoice which shows 8 Ignition coil WP-111280 at $133.23 each. I don't find a manufacture label on the coils and have not located an associated coil pack part number. The following is embossed on the sides: 5131 with 20.09.16 marked below the 5131. If the coil packs actually cost this much in 2019, surely they would be of good quality!?!?!? I see the NGK brand coil packs have these letters stamped on them. I would gladly replace all packs to resolve these ongoing issues! I understand that a defective coil pack can cause other coil packs to appear bad so buying a new one to substitute in for each in turn would not seem to allow for accurate diagnosis???

*******New this morning....may not be related to any of the above problems but I no longer have the fuel lid and trunk lid opening function. Not with the key fob or the buttons on the dash. My car doesn't have the printed "map" of fueses which should be affixed to the lid on the trunk fuse box. Anyone know where I can find this to create a replacement??? Way better solution on the road than pulling up the fuse diagrams for each of the separate boxes to find the location of the offender.

 

He's a tad over-optimistic about the interior trim...

You really need to eliminate this from the list of possibles. You can check for shorts to ground or B+ on the coil feedback circuit by probing the Yellow/Green wire (pin 3 2) to the coil module on any of the affected cylinders. I appreciate it's harder to track through back to the ECM as you'll need to lift it out of its location to get to the connectors properly. Note the yellow/green wire colour is maintained throughout back to the ECM - connector EM83 pin 10 11 for the cylinder group involved here.

The ECM will probably flag P1368 again once the pending P0352 becomes current.

Swopping out (or disconnecting) one coil module at a time will eliminate the possibility of one in the group affecting the others, unless you're incredibly unlucky to have two with exactly the same fault. You previous checks seem to have eliminated this, though.


Best if you start a separate thread for this:- does the top still operate normally?

Jaguar seems to have stopped providing them some short while after the 98MY. However, you can order one from your local friendly dealership (part # LJB2870AC*) as Heritage shows them available:
https://parts.jaguarlandroverclassic...lid-label.html
...but might be possible to source from a breaker.


*According to the JEPC for MY2000

 

I am not sure I understand how to check the disconnecting of one coil at a time to know if a coil is bad/is causing the problem?? I have re-read the discussion post on this above. I did not clear the fault codes and read them each time I disconnected one. Is that what I was supposed to do?? If not, then how would I do this exactly?

 

For each of the two cylinder groups,yes, the Yellow/Green wires are spliced together (see PIS11 & PIS12 top left in the diagram) then run as a single wire back to a pin on the ECM connector: two wires in total.
Here's a snip from the 2000 Electrical Guide:


Apologies:- I got the pin numbers wrong. I've corrected my previous post. The wire colours are correct.
With the ignition turned off and the multimeter set to ohms, measure the resistance from one of the coil packs pin 2 to ground, then from pin 2 to battery positive. You can find B+ on the metal stud on one of the fuseboxes in the engine compartment (usually covered with a rubber cap). For example:


I'm not certain of the exact resistance, but you can compare it with a reading from one of the coil packs in the other cylinder group, as we know that is functioning correctly.

If the problem is being caused by a faulty coil module affecting the others in the group, I'd expect to see only codes relating to the cylinder with the disconnected coil module. Strictly, clear the codes in between each test, but the engine will run noticeably better on 7 cylinders than the present 4.

I hope this all makes sense.

 

I re-ran the test involving disconnecting the coil packs to cylinders 3, 5 & 8. The codes found before doing any disconnecting were: P0308, P0352,53,55 & 58.
I cleared the codes on my reader and....
Disconnecting coil on cylinder #3 , the codes found: P0353,55 & 58
cleared the codes again and...
Disconnecting coil on cylinder #5, the codes found: P0352, 53,55 & 58
cleared the codes again and...
Disconnecting coil on cylinder #8 , the codes found: P0353,55 & 58
Soooooo,
The only difference in the codes thrown while running the engine with a particular coil disconnected was the codes found when disconnecting on cylinder 5. With this one disconnected my reader showed one added code: P0352.
could this mean that the coil module on cylinder 5 is the one that is bad as it threw an added code??

 

After posting my last, I re-read the advice I received from Michaelh-147158/ and realized that I should take another reading with the suspicious coil unplugged to see what codes would be reported. I unplugged the coil on cylinder #2 which is one that was mentioned by Michael in an earlier post as a possible. When I viewed the codes after doing so the only code I had was the single P0352!!!!!! Never before did I have a reading without multiple codes. I then did as Michael had suggested (again in a previous entry) and switched the coil packs of cylinder 2 with cylinder 6. Now the suspicious coil was on cylinder 6. I left it plugged in and ran the engine so I could view the codes. New codes reported P0351,54&57. These were different that the fault codes I had been getting before switching the coil pack accross the engine. So, to confirm, I unplugged the suspicious coil (now on cylinder 6) and ran the engine to pull the codes. The only code to display is P0356. This is what Michael told me to expect if the defective coil was removed from the system as its absence would allow the ECM to leave the other coils in play and the engine would run on 7 cylinders.
I can't begin to express the pure JOY and sense of relief in being able to know with a great degree of confidence what has been haunting this car for most of the year. A huge debt of gratitude is owed by me to Michael for the incredible knowledge and time shared with me on this project. Sadly, if he had been working with a more experienced Jaguar owner, I may have done a proper job of executing the testing that he suggested earlier. For the record and whatever benefit it may be to others reading this, My error was in no clearing the codes after each time I previously unplugged a coil pack. Also, I was expecting to see an error/fault code for the bad coil when it was plugged in and affecting the others. As you will note, when I moved the bad coil across to cylinder 6, the codes that were reported did NOT include P0356! Lesson Learned I hope!

 

I can't rationalise that either, although you did report P0352 intermittently. However, moving the coil module to the other cylinder group, with the codes then following it, is pretty conclusive.

Well done!