Hi all. I'm a bit stuck with an issue on my XJ8. It starts normally but after a short time goes into restricted performance. DTC codes are misfires on cylinders 2, 3, 5 and 8, p0352, p0353, p0355, p0358, p1368. If I clear the codes, they come back, always on these 4 cylinders. Swapping one of the coils for one of the cylinders made no difference ( I didn't think it would but it was an easy check). Any ideas​? What would cut these 4 cylinders? The car has 130k miles and has been running sweetly for ages until this started...

Thanks in advance!

Andrew

 

I had a similar problem around the same mileage. Ultimately I had to replace the engine control module. My mechanic says that this is a pretty typical problem - and you can only get the part from the dealer and they have to install it.

 

Ouch... Thanks for the quick reply. Any way to check if that's the problem?

 

Not sure. My mechanic says that the ECM is the one thing that is hard to diagnose because it is the source of the diagnostic codes. If it is bad, how does it know what it is doing? Sort of like asking a doctor with Alzheimer's to diagnose himself.


Sorry not much help. just don't let any mechanic start replacing coils before checking the module.

 

Have your spark plugs been replaced? If not go ahead replace all plugs and coils.

 

I would replace all the plugs first.

next I would run fuel injector cleaner such as Techron through. A cleaner that you connect to the fuel rail would be heavier duty option.

lastly, would be to disconnect the control module, check the connectors and reinsert the connector a few times and retry. Its not likely all the coils

Good luck and keep us all posted

RyeJag

 

In my Alfa 164 there are a pair of ignition modules each regulating 3 cylinders on each side of the V6 engine. If swapping the ignition module switch the fault codes on the other side then you know which ignition module is bad and need replacing. Knew XJS and X40 have such ignition module (DAC10923) (see picture) but don't know whether X358 has similar set-up.



Anyway, if it is always one side of the V8 that causes the codes, it could be a connector or harness issue. No harm changing the plugs if they are due for replacement (every 100,000 miles?), and take the opportunity of inspecting, disconnecting and reconnecting any connectors as ryejag suggested when replacing the plugs.

 

The coded misfires are on opposite sides of the motor and are also not in the firing order sequence so it's not a fuel rail supply problem or a mechanically coupled problem. Unlikely that 4 coils would fail at the same time or that 4 plugs would also do so...although if they've been in the car since new they're toast by now.

The P1368 code indicates an fault in the "ignition monitoring circuit" on the "left hand cylinders" which may be the case but you have misfires on both the left and the right so even that is misleading as I would have expected a P1367 to take care of the right side misfires as well.

In any case you have what I suspect is a short circuit, bad ground, or failing in what they refer to as an "ignition amplifying group A or B (or both)" which requires some pinpoint electrical tests of the specific connectors and pins called out in the appropriate "pinpoint test" sections in the 2004 SVC. manual.

Download that manual from here: https://www.jaguarforums.com/forum/x...k-links-20085/

It's in 6 parts and is about 1/2 way down the page.


You'll need a decent multi-meter and the electrical schematics ( available here from a member:

http://www.jagrepair.com/images/Elec...al%20Guide.pdf

and a lot of patience and study because it can be a bear. Not impossible but you'll need to teach yourself how to follow their shorthand abbreviations (they make a list) and work patiently until you get the hang of it.

Basically connect to pins with the multimeter and take a reading (using the right scale of course) and answer yes or no at each step.

 

How's your battery?

My 06SV8 with similar miles started doing a very similar thing throwing misfire codes and displaying the restricted performance message when it was started and even once turned on the screen wipers that were set to auto and puffed out a cloud of smoke from the exhaust. When I checked the battery voltage while cranking the starter it dropped to 11 volts so I bought a new 900 CCA battery and after it did some odd things "relearning" how to run again from the battery being disconnected, it has been OK ever since. It even seems to have more power (although that may be due to it still re-learning the shift points).

 

Thanks for your ideas, everyone! Plugs, coils and battery are new enough that I don't think they're the issue. Going to have a good close look at the connections next.

 

hello, ive been having this exact same issues with my car same year and mileage. im giving away money because folks keep checking car and i get a diffrent 3000 possible problem quote each time. The car runs quiet but rough. I get a putting from the exhaust but when i hit the gas its true. I do notice a smell like a bad converter but that might just be because of how its running. All plugs are clean. Any solutions on how u fixed ur car would be great. Klfloyd98@gmail.com 3132205877

 

A bit of a long shot but check the drain under the cabin filter.

A blockage here can cause water to get into the ECU connector.

 

Just a follow-up this most likely result for this person but I too had restricted performance issues with my Jaguar 2004 XJ8 that turned out to be fuel injectors issues initially misdiagnosed as the main module unit. But somebody made a perfect comment regarding that unit was not the issue like asking a doctor with Alzheimer's to diagnose issues of course would be very unreliable. In any case I ended up replacing with Bosch fuel injectors that perform excellent and resolved the restricted performance issue.
regards....

 

​​​​​I had a bad experience with the fuel injection cleaner on my 2006 xj8 on 22s aka pimpdaddy
. What happened was that I believe it clogged up the fuel pressure sensor with gunk that it threw out a bank 1 too lean code. It would jerk Howevern tug n even not start sometimes when I would drive it all day. I replaced the sensor n got rid of the code. Which solved the problem. Put in new suspension. Alternator 3 weeks later this dickwad slamez the rear end at 50 mph.

 

Did you ever find the solution to this problem? My 2004 XJ8 is doing the same thing, same codes, same restricted performance light.

 

I didn't... but the guy I sold the car to replaced my aftermarket coil packs with known good OE ones, and that seemed to sort it, which was frustrating, since I sold it cheap, lol... I hope this helps, loved that car...