The car in question is an ’02 XKR.
Does anybody know the number of drive cycles needed for a P0400 code reset? About a week ago my CEL lit up with three codes: P0400 (EGR flow), P0171 and P0174 (Bank A and B lean running). I took apart the throttle/EGR valve assembly and found that one of the EGR valve mounting screws was missing and the other one was loose. The only thing that held the valve on the intake elbow must have been the carbon build up and the “sticktion” of the gasket. Just to ensure that I do the job once I cleaned the valve, removed and cleaned the EGR pipe and replaced all of the gaskets.
After reassembly the rough idle that I was experiencing when the fault code set is no longer present. So I believe I have fixed the problem. I drove the car to work and back (about 45 km round trip, suburban-type driving), it appeared to run fine. I was expecting the CEL to reset itself after two trips, but this morning it is still there. I checked the codes and they are still present and cannot be erased with my cheapie code reader (mainly because I have an inactive C1175 wheel sensor fault lurking in the memory).
After how many cycles does the CEL reset itself?

 

Quick search pulled this up:

https://www.jaguarforums.com/forum/x...e-cycle-76029/

 

I'd expect you'd have to clear the stored code before the CEL will go out. If the underlying cause has been fixed, it will then stay off. If it hasn't been fixed, it will reappear within two drive cycles.

Graham

 

My code reader is unable to erase the stored faults. It comes up with "Erase Fail". I believe the problem is that in addition for the three P-codes I have a C1175 code stored in memory that my reader tries to reset at the same time. That's why I'm trying to figure out the drive cycles needed for the CEL to reset itself.

I guess there is a possibility of the EGR valve itself being faulty, but that would be too much of a coincidence..

 

Until you rectify the issue with the the left rear Wheel Speed Sensor, the C1175 will persist.



As long as that code is stored, the CEL will stay illuminated.

Graham

 

Until you rectify the issue with the the left rear Wheel Speed Sensor, the C1175 will persist.



As long as that code is stored, the CEL will stay illuminated.

Graham

 

I just recently had the P0174 code on my 2003 XK8. I cleared the code and it has been a couple of days. The code has not reemerged as of yet, but could you give me some direction of what you did and tell me what to look for. I thank you in advance.

 

Here's the list of possible causes for code P0174 from the Jaguar DTC table for your MY:



It can sometimes just be an out-of-range signal from one of the sensors to the ECM so it may not come back.

Graham

 

Just to answer my own question: It took ten 22 km drives and approximately 20 power-up cycles to reset the CEL caused by P0400, P0171 and P0174.
On a side note, my code reader does not appear to be compatible with Jag-ware.