Hi All I’m new to this forum. I would greatly appreciate if someone could throw me a lifeline Please.
I am currently tearing my hair out with a set of error codes with my 97 xk8
(i have changed all ignition coils and subsequently swapped out the ones A,D,F and G.
The 5 codes are
P0351
P0354
P0356
P0357
These 4 codes relate to the ignition coil linked to one of the two ingnition modules
P1367
This a ignition control module
My car defaults to 'limp home mode' after starting an running normally from cold for a couple of minutes. If the car is restarted with a warmer motor the time till 'limp home mode' reduces.
The transition from normal running to yellow light, limp home is instantaneous.
Engine scanning gives identical codes to what you are getting.
I have eliminated the 4 ignition coil codes by swapping the coils into the good positions. This gives no change in the error codes indicating the problem is not with the coils ( also checked all coil impedances and they all indicate 1.2 ohms)
I have swapped the ignition modules, once again no change in the codes
I have checked all multipin connectors
I just don't know where to go next.
It may be a broken wire but everything looks rather pristine in the engine bay
It may be an engine control unit, no way I know of testing it.
Any help greatly appreciated

kind Regards
paul.

 

Look at the wiring diag, the coils are neg trigger and should have power and the power may be spliced together which if ahead of the splice will kill all down leg circuits. Pin the harness for contibuity from ecm to coils. Once you elimnate the wiring then you can send the ecu out to be repaired telling them your faults so they can address those. All this is off the top off my head so look at the diagrams to determine exact course of action.
Remember looking good and being good are to totally different things on people and cars

 

Sorry to hear the Cat is down but you’re doing the right things.

You’ve done everything sensible. Sending out the ECU for repair is the next logical step.

 

Hi, I'm new to this forum as well. I'm wondering if you ever resolved your issue? My 2001 XKR is giving me similar codes, p0351, p0354, p0356. And if I run it long enough, p0300. Difficult to run very long, because cylinders 1,4, and 6 are missing most of the time. I started by replacing all plugs and coils. Then I read here that it was probably the PCM. After changing that with no difference, I ohmed out all the wiring, which is rather difficult, and took a lot of time. All the wiring checks good, 2.2 ohms from the PCM to the coils. Each coil wiring checked exactly the same. So it's not a wiring problem, and I believe I've replaced everything else in the circuit. Any ideas? The car has been out of commission for almost a year now, and I had to buy a different car to replace it. I just want to get it running so I can sell it.

Thanks, Bob

 

Bob, the OP hasn't been back since June so we may never know whether he solved the problem. In his case, it likely was the ECM (97 for some reason was a bad year)

Member johns55 has recently been through a very similar journey to you. Read his thread here:
https://www.jaguarforums.com/forum/x...4/#post2071724

Good luck!

 

The 97 ECM suffered from leaking capacitors. Mine included.

 

I was hoping that was it, replacing the ECM made no difference. Having checked all the wiring, and swapped the coils and plugs around with no change, I'm really at a dead end.

 

Bob,

Sorry to hear about your misfire woes. You seem to have addressed all of the electrical side. You’re understandably frustrated with random misfires but have you checked some other stuff
1. Possible bad fuel
2. Fuel pressure at the rails?
3. Compression inside the cylinders
4. Blocked/open injectors
5. Spark at the bad plugs/missing cylinders

 

Hi David, The fuel is good, (that was my first thought). Fuel pressure is normal, 38-42. I've swapped plugs and coils from good to bad cylinders, also swapped injectors with no change. I haven't checked compression, but still think it has to be electrical, since all 3 cylinders starting acting up at the same time.

 

That implies a common cause, but not what that cause is. OBD codes are meant as a guide to aid fault finding: they won't always point at the faulty component ("why do our cars lie to us"?)

johns55 pretty much exhausted the electrical route (as you have) and turned his attention to fuel supply. A replacement pump seems to have fixed the problem.

Another $0 check you can make is to remove the fuel pump #1 relay in the trunk fusebox and see what happens. The car will throw a P1230 and restricted performance, but forcing the other pump into action may shed some more light on what is happening:



NB The second pump on the R only runs when the fuel demand is high. Consequently they can die without its being immediately apparent.

 

Thanks for the idea about the fuel pump relays. Unfortunately, pulling either one of them makes no difference in the way it runs, which leads me to believe both the pumps are working. Still baffled.

 

Bob,

Really weird one and you’ve seem to have everything covered, including the ECU, but....

1. Have you physically checked you’re actually getting a spark at the 3 plugs?
2. If fuel and spark are good, then you’re onto looking at the air side.... but that would affect performance generally
3. Have you checked compression at the 3 bad cylinders?