2000 XK8 Convertible. Car runs fine but engine light will come on and car will go into restricted mode. Pull over and restart engine and restricted warning light goes away but engine light stays on. OBDII has no major codes. Reads P1000.
When we clear the fault the car will run fine for a couple of days and the process will start again. Can't seem to locate the problem. The car performs as it should. This light coming on is getting frustrating. Any thoughts? Last week I replaced the air mass flow meter. At the time I was getting a code that read to lean. The new meter solved that problem but not engine light. Also, recently the car had the hydraulic hoses replaced for convertible top. battery was disconnected for long periods during repair. Don't think this is relevant though. Thanks in advance for any feedback!

 

Check your battery & do a hard reset. Can't hurt and it might be that simple.

 

P1000 is NOT a fault code - it's a status. You will ALWAYS see:

P1000 : the on-board diagnostic tests have not been completed since last memory clear
OR
P1111 : all on-board diagnostic tests have been completed

When the MIL is illuminated there has to be a code or codes set that have triggered it. If it happens again after a hard reset, post the actual codes back here.

Graham

 

+1
if MIL is on you have a code (not counting P1000/P1111) so if your tool says not then change the tool.

 

Thanks to everyone for the help! The codes are P0171 and P 0174.

 

Carefully check the intake bellows for cracks and make sure it's seated properly to the gasket on top of the throttle body.

 

Thanks, that seems to be okay. I re-seated just to make sure. I'm sure it's something to do with that system. Just replaced the Air Mass sensor too.

 

If you have a EGR valve it's possible the screws have come loose. This was a problem I found on a 2000 XKR, and several others have also. Unfortunately it's hard to diagnose and even harder to fix without removing the throttle body.

Try squirting some flammable solvent under the throttle body with the engine running but the cats not hot and listen for a change in engine note/ idle speed.

The tube from the top of the right cat to the EGR valve is another suspect.

 

Worth reading existing answers about P0171/P0174.

 

Had the car smoke tested. No leaks found. I was able to get a complete diags report at a local shop. I've attached the report below this post. This is still a mystery but it seems there are some communications problems within the electrical system and network. Any experts out there that can lead me in the right direction, would be appreciated very much!

 

XK8 diagnostic report

 

I would not worry about the communication error unless it consistently recurs after clearing the codes...it could have been logged any time in the past.

The lean condition could also be caused by a clogged fuel filter or a weak fuel pump. Have your fuel pressure checked.

 

Thanks. Fuel pressure is good and car has new fuel pump.

 

Mine turned out to be the lower part load breather hose. Very brittle plastic part prone to air leaks.

 

I would have to agree. They may have missed it with the smoke test. A better test is to monitor the fuel trims with an OBDII scanner while spraying carb. cleaner at potential air leakage points.

 

Also, watch fuel trims at idle & again at 2500rpm. (See previous threads for more.)

 

Ok, finally solved! 2nd smoke test with more PSI revealed small leak coming from a smaller hose into the main snorkel before the bellows. Mechanic said that would explain the lean on both banks condition. Thanks to all for your input. I just hope this will stop the restricted performance state that occurs. I'm sure it will cure the engine light problem. Tomorrow after new hose is fitted, I will clear the codes and update on the progress of the vehicle. Pretty happy camper right now!

 

That is probably the full load breather. Hope it works.

 

Codes are back. Restricted Performance at idle. RP goes away after I drive a mile. Car seems to run fine. Back to the drawing board. I found a Jag service bulletin. See post below.

 

Hesitation, Surging, Detonation, Poor Throttle Response/Acceleration – Diagnostic Flowcharts – AJ 26 Engines