I just put my XK8 on the road and it needs some help. Has these codes ; P0351, P0354, P0356, P0357, P1376. Car has 65,000 miles but has not been driven much in the last three years.

 

Needs some help covers a lot of ground....

Does it turn over? Run? Idle? Is the battery newer than 6 months?

 

Battery is good, car runs and idles rough. ran good for about 30 miles then trouble started. Some research points to ecm ( bad capacitor )

 

...Have the secondary tensioners been replaced with metal ones?

Is the battery newer than six months? I have seen many problems stem from a poor battery (usually multiple codes) As a matter of fact I looked at a friends' jag yesterday that threw up a bunch of codes (similar) after sitting for a long time. Cleaned up the corrosion on the positive side, cleared the codes and he was good to go.

Check the ground straps and bulkhead connector while you are at it.

 

Hi Paul
This is very interesting!
I am currently tearing my hair out with an identical set of error codes with my 97 xk8 (see my posts)
To summarise ;
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 can't believe that it is the ignition relay as from studying the wiring diagram any failure of the relay would have to affect both modules
I have checked all multipin connectors
I have looked at the large junction on the firewall behind the throttle body.
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.
If you have any joy in solving the problem please let me know ASAP (winarnie1@gmail.com)

 

Tonight I removed ecm, looked it over and reinstalled it. Before starting I switched ign. control modules. No codes, drove for 15 minutes still no codes. Put ign. control modules back to original and started. Runs fine. I hope it was a connection that was corrected by my actions. We will see on some longer drives.

 

Hope you have had a win
I will try the same
Where is it located
Kind regards
Al

 

The ECM is in the compartment in the right side of the engine compartment against firewall and ignition modules are on firewall directly behind engine. I have not made a proper test drive yet, I don't like when a problem is gone without knowing what caused the problem. It usually returns.

 

Hi guys - I'm currently having the EXACT same problem with my '97 coupe. I thought for sure it would be a bad ignition module, since it's the only thing 4 coils would have in common. As with you, swapping the ignition modules did nothing. I just removed the ECM and doused the connectors with CRC electrical contact cleaner. Now every time I try (unsuccessfully) to start the engine, my scanner gives me different fault codes from the ignition coil circuit codes I was getting before (P0351, etc.) Now I'm getting codes for one of the TB sensors and a couple of others I can't identify. Have you been able to find a fix for this issue? At least a temp fix that will allow me to get the car to the...forgive me...local Jaag dealer under its own power? THANKS!!!

 

The best thing that could happen is not being able to get it to the dealer. I had the same problem and determined it was the ECM. The dealer will probably agree and want to sell you a new one for about $7000 installed.
Contact Automotive Scientific Inc. in TN and arrange to have them test it. It cost me $55 last year, although shipping and insurance added about $70. If the unit is faulty and can be rebuilt the testing cost will be included in the repair price of less than $400, and the will provide a warranty on the repair.

 

The problem was the ECM, I sent it out and had it repaired and no more problem. I removed ECM cover for inspection and found a leaking capacitor that had damaged the board. I don't put a lot of miles on this car but it runs pretty good. I am afraid it has the early block in it .

 

I am getting off the subject of the thread, for which I apologize, but feel it necessary to comment on the AJ26 block.
Nikasil lined engines are excellent, but are much more likely to be damaged by overheating. It would be wise to invest in a monitor that is able to read the actual temperature.
I purchased an Ultragauge shortly after buying my XK8, and later installed the Realgauge mod from the jagwrangler. Both of these have an alarm for added safety.
The Ultragauge is now in the XJ6.

 

Thank you all for the valuable input! I'll definitely get in touch with Automotive Scientific as you suggest and will report back on the outcome. On the topic of engine overheating, I'm seriously considering switching to NPG (non-propylene glycol) waterless engine coolant. I know it's a bit pricey, and I've read much on the debate over the cost vs. benefit issue, but the fact that it doesn't require the high pressures used by conventional cooling systems indicates that it would be much less likely to fail, leak, deteriorate, clog, etc.

 

Hi again - I wanted to follow up to let you know that I got the rebuilt ECM back from Automotive Scientific and just finished a 2 day, 500 mile road trip. The Jaag performed flawlessly, and an unanticipated bonus was vastly improved fuel economy. I got almost 24 mpg averaging 65 mph, whereas I had been struggling to get 18. Many, many thanks again for all the valuable input and stellar advice!!!

 

Thanks for reporting the results. The specific set of codes appear to be a strong indicator of ECM failure in the early model cars. Something all 97-98 owners should be aware of.