For my: 2012 Jaguar XJL Supercharged 110k miles
Periodically, I keep getting an error code: "intake air temperature sensor 1 circuit high bank 2". My engine light will come on. Currently, I have the engine light, plus the "Restricted Performance" yellow icon.

Please Help!!! :-)

I have cleaned the MAF sensors (2 of them). I have even tried to replace them with (Not OEM) sensors. I'm thinking it is something else?? Does anyone know where this Intake Air Temperature Sensor is located? I can't seem to find a diagram to pinpoint it. I think it's on the manifold underneat the engine cover, and not the MAF sensors. Do you have any advice? This error is driving me crazy. I have spent so much money on repairs of this XJL, it is draining the life out of me.

 

What are the codes? What scanner are you using?
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"Circuit high" usually means that the top range of voltage received by measuring unit. Possible short circuit between signal and positive wire.

 

I have used different scanners. The one I have (generic one for all my cars now) is a Foxwell NT301 Plus scanner. It shows code: "P0102 Mass or Volume Air Flow A Circuit Low". I also get code: "P0441, Evaporative Emission System Incorrect Purge Flow". Using the Auotozone one, I got: "P00AD Intake Air Temperature Sensor 1 Circuit High Bank 2" and "P0500 Vehicle Speed Sensor A".
Talking to my Jaguar mechanic, he said I can't use those scanners, Jaguar requries a their own software ones. So as a favor, he told me to bring it by his shop to scan it with his tool (This shop is awesome, top notch guys). They didn't give me the code as they were goign over it, but came to the conclusion that I would need to drop it off with him to do a thorough diagmostic on it. I'm just running out of funds to keep bringing my XJL to the shop, I've spent thousands $$ this year on repairs.

The mechanic mentioned something about the intake air temperature sensor, but would need to research it on his schematic, and would do that if I dropped it off for another repair. I have 2 MAF sensors. Whoever owned the car before me, must have replaced them in the past. I see 2 different types. I don't think they are OEM. (See photos attached). Jaguar OEM ones are like $400 each, $800. So before I start throwing parts at it, just want to make sure I'm buying the MAF or if it's this other air temperature sensor thing somewhere??

Can I use the Denzo ones? PN: C2Z2989. They are only $140 each. Or am I forced to get OEM? LOL...Or is it something else? I'm going crazy here.

MAF Sensors:

 

Not an expert, but I believe air temp is calculated at various times using three different sensors (pre-combustion/ exhaust) :

- Ambient/exterior air temp is measured via the ambient air sensor (C2Z5465)
- The MAF sensor (C2Z2989) measures air intake by measuring changes in temperature to a heated wire. Denso makes the original part for early models, so the Denso part should be fine.
- If you have a supercharged XJ you should also have a MAPT sensor (AJ813840) which measures manifold pressure and temperature.

 

Nedoerr, thank you so much for this information! I will look into these options you provide. Additionally, I "May" have found one of the problems. Currently, I have the engine light on, and an alert "Restricted Performance". (car is in safe mode from what mechanic told me). Yesterday, I was lookign at it again, and I noticed a vacuum tube (someone before me put a fuel line on this thing!??). It was loose. So I took the line and zip-tied it down tight on the connection to squeeze the connection better. Just to see if that would do anything, and my "restricted performance" light went away. But, engine light is still on, will need to drive it.
But this code has haunted me for a couple years now. I believe there may be more to it, and the info you provided me will definitely help. I'll try those options.

Thank you (and everybody helping) with this. I'll keep you posted. Internet forums are a great thing.
Respectfullly,
Bryan.

 

Loose vacuum hose I found, loose at the connection to the airbox system near red arrow:

 

Good fix but a vacuum leak should have set a lean code? You did not have a code for this?
Has the car ever been hooked up to a Jaguar SDD system?
Maybe you don't have the right codes yet?

I would forget the temperature one as that came from Autozone. The codes posted are nonsense and don't mean anything. Has any other scanner given you the temperature code?

I wonder why both MAF's were changed and if we knew the reason it might point to what your problems are? Can't say if you should replace them or not but very little MAF problems are reported. Mainly MAF's needing cleaning. It's not great they don't match but who knows?

I would have that hose replacement on my to do list!
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