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Seems like I am the only person with this issue as I have not seen any posts regarding this error code. I just picked up my dream car - 2014 XJR (long wheel base) and I'm starting to have a nightmare given the issues I've been having... but nonetheless, one step at a time. I've noticed my car has been struggling at idle (hunting idle with slowly revving up and down) with poor performance. It has now started to stall when idling after driving for a short period of time.
The error code is P012B - Supercharger inlet pressure sensor circuit range/performance. I know there is a variant code with a C and D at the end (low and high voltage readings) so I'm not sure how my code varies from these. In any case, I've located the one sensor on the inlet on near the top of the supercharger. I took it off, sprayed brake cleaner, let it dry and reconnected while clearing the code. Seemed to work briefly and it's back to square one. In trying to find a replacement part that is not with dealer markup prices, I've noticed this car seems to have two of these sensors (with different part numbers according to Jaguar reference)
I'd really appreciate if someone can help me find the second sensor's location before I purchase one (or both). If you guys also have a cross reference part number for replacement or any other advice, it would be GREATLY appreciated!
Side note: the sensor located near the top of the supercharger has Ford 6G91-12T551-AB written on it.
Last edited by WiredNinja; 08-15-2023 at 11:07 PM.
While I wait for any help, just letting everyone know that the supercharger location with Ford 6G91-12T551-AB written on it can be had for about 1/3 of the price depending on what model/code you search for. I just happened to find one on Amazon Canada for $60
Update: for anyone having these symptoms, it solved my problems. Not only did replacing the one sensor (at a much cheaper price vs dealers) fix my idle issues, it restored all power throughout rev range, even at the top end with slight engine hesitation. Furthermore, I also don't have my O2 sensor codes coming up (so far). It's very possible that since this sensor measures pressure and therefore the rate at which fuel gets dumped in the engine, the failing sensor caused values in the exhaust side to be off as well; causing the O2 readings to be erratic. Strange since this code is fairly new - but the problem did get worse over time until complete failure it seems.
Change these cheap sensors if you have any of the problems I had!
WiredNinja thanks much for the part number help and coming back to finish up your repair!
I have not had great luck with the URO brand (Suspension parts) but it is much cheaper than Jaguar's part.
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Generally, sensors and the like are very much interchangeable (with same part numbers) as they are manufactured to perform a certain task - so the standards are pretty much the same. In fact, for that one sensor I've found there are about 10 different part numbers! (ie. Ford, Jaguar, Land Rover etc). For other items like suspension parts, gaskets etc, it may differ slightly and thereby perform different. If you are able to have the original part and then compare side to side with a URO or other brand of part, you should be able to see this. So if you can't see or measure any differences, you are good to go to save literally hundreds of $$
Thanks for posting this! Just so happens that I got a very similar code today: “P012D Supercharger Inlet Pressure Sensor Circuit High Downstream of throttle valve”. I just reassembled the supercharger and coolant system after upgrading parts. It’s great to know what sensor is the troublemaker…this is the sensor attached to the supercharger snout right?
I installed the URO part for the oil cooler connector tube URO product LR028136PRM
08-15-2023, 08:18 PM
XJR P012B - Inlet Pressure Sensor
