Hello all. I have a 1999 jaguar xjr and these three codes appeared today: p0121, p0157 and p0507. The p0121 code has been coming on for a few days, the rest appeared today, I'm guessing as a consequence of the p0121 code. The p0121 code is referring to a throttle body sensor, the p0157 is an O2 low voltage sensor and the p0507 is a high rpms notice. In the not too distant past, I changed the throttle body and a p0120 sensor. I am wondering if anyone might have any ideas as to what might be causing this issue. Also, I have cleaned all sensors in the not too distant past as well. Thank you

 

https://www.jaguarforums.com/forum/x...ncerns-159443/

The above link may or may not help. Yours is also an AJ26S like the 98’ is. The P0121 could be a result of many things. The issue I had is that the replaceable sealed roller bearings were seized up inside the TB. The throttle cable drives one side of the throttle body and in turn commands the motor on the other side of the TB to adjust the butterfly open or closed. Having seized or sticking bearings certainly through strange codes because there was confusion between the TB and ecm.
This was only one example but follow the above link and report back here. There were TSB’s pertaining to the same P0121 code. The ECM is also another weak point in these cars.

 

Thanks for the analysis. I'll look into finding these bearings and see what condition they're in.

 

https://www.jaguarforums.com/forum/x...e-body-275663/

Looks like your both in the same process at the same time. I’ll see if McMaster Carr has my order history to pass any further information to.

 

Ok. Thanks for your help. Ideally it would help knowing what they look like. I'll keep looking online to see if I can find a picture. Thanks again.

 

Yeah, I logged back in to McMaster and there were no past orders to view even though I know 100% I ordered from there. It was just so long ago that they purge those things every so often.

 

I came across the old bearings I took out. I only did 3 of the 5. The top and middle photo go together as this was the old bearing and the updated P/N above it was the replacement. The bottom photo is a Koyo and it should be a 609-2RS updated part number. This is just for future reference if you or someone else needs this. The original bearings are made by Koyo and the replacement was by SKF.

 

Thanks for showing me what they look like.