HI folks,

SO, Daighter's 2001 XJR is going into failsafe mode on occasion- sometimes at a stop light, and recently right when the car is started. It is VERY sporadic so I am having a hard time hunting down the problem and don't want to assume it's the TB. The last code it popped up was P1222. Here is exactly what happened:
1. Started car, barely warm ran perfectly
2. Drive 9 miles freeway speeds mostly, 1 mile regular roads
3. Parked at local electronics store (Fry's for those who need details)
4. Attempted to purchase something but then got frustrated with employee as he insisted I give him all my information to buy a regular telephone...
5. Jumped in the car (and this part may or may not be important) jammed the key in and quickly started it.
6. Immediately notice rough running and failsafe mode
7. Turned car off
8. Slowly turned key and started the car (ran perfectly and smooth)
9. Drove home and pulled codes

The reason I mention #5 is that my daughter tends to jam the key in and turn it fast more than I do because she is always in a hurry and I have not had the failsafe issue when driving it until yesterday....is it POSSIBLE that we are having an ignition switch issue? I have an XJ8 that I can pull one out of if I get support on that.

 

UPDATE:
Went into failsafe, and I checked the TPS% while the car was on but not running- it was 7, then 6.6 and I believe it should be around 3.x correct?

I am now thinking TPS. Are the XJR and XJ8 TPS the same??

For that matter are the XJ8 and XJR AJ27 throttle bodies the same?

 

Disregard the last post- Now reading 3.9 at rest. Failsafe again, and knock sensor 2 code this time. after turning off and on a few times failsafe went away. Any ideas?

 

on the way out the door, so very short here.

- insufficent voltage/current at start, battery weak from short trips

- fuel pump on the way out

- i always wait for computer to fully boot, all self check lights extinguished in
insturment pack except oil pressure

 

swap the TB and it will work.

 

Thanks guys- gonna try swapping the TB and see where that goes.

 

Sorry to bring back an old thread. But did you ever solve this?