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Hey Dibbit many thanks your response that is exactly what I was wondering. I followed procedures for checking the TPS (orange wire on connector) with a multi meter and only had 0.05 v at idle no voltage increase with throttle movement. Did I do that correctly? Again, big thanks and I’ll report back with my sensor swap outcome.
The TPS is two sensors in one, so there are two separate outputs. There should be a constant 5 volts on the Orange/Yellow wire, and ~0 volts on the Black/Green wire.
The outputs on the Brown and Green wires should vary somewhere between these two values as the accelerator is pressed, although they will be different.
You could mark the position of the TPS on the throttle body before removing it. The one on the XKR (same part #) is set pretty much mid-way between the limits set by the slots for the securing screws.
NB Someone mentioned 5-point torx - you will need one to remove the securing screws.
Michael I will take your guidance over AI anytime! Thanks for letting me know the proper way to test the sensor and this is what I found
Idle: WOT
orange 0.05v no change
brown .64v 3.85
green 1.53 4.07
I didn't see the voltage fall off going up or down thru the range. I also tapped on the sensor while monitoring each wire. No faults noted
This is why I don't like checking sensors and switches because electrically they will check out but many times it will still be bad. It seems to me that the car is having a problem sorting out the change from driving to stopping (idle). However, I did get a fault after starting and idling for a short time.the same night while the vehicle was hot.
I will mark the sensor and get it 100% where the old one was. Michael the numbers look right to me but I don't know what they should be?
As you say, however, simple checks don't necessarily prove the TPS is functioning 100%. The two outputs are sanity-checked by the ECM, which will throw the P0121 if what it sees is outside it's programmed margin of error.
This could happen if the two pots in there are wearing out (think crackly volume control on a radio), which is unlikely to be picked up in a simple meter test.
As they say let's see what happens lol. I couldn't agree more about sensors starting to break down and heat usually doesn't help the situation. Thanks as usual and I'll report back with the right results.
I wanted to let you know the sensor swap was successful, "ding dong the witch is dead". Two things I wanted to pass along to anyone wanting to attempt this fix. Mark the sensor and change the screws. The mold mark on the sensor (Denso) is a good place to mark the throttle body for the new one.
There is one of these marks on both sides.
I assumed between my motorhead neighbor and I that we would have every size bit that's ever been made, but no. After 20 minutes of trying to finesse these screws out I finally used a needle nose Vice grip to get them out because I knew I was changing these screws to something I actually have a tool for..lol
I found these at my local ACE hardware store. The screw length is about 1/2" and I used stainless $2.28 out the door
Cleared the codes before disconnecting the battery.
Swapped sensors
Hard reset
Reconnected battery
Stated the car and let it idle for 5-10min
Shut off
Took it for a 20 mile run in mixed driving
All perfect including the start up and idle and it never sputtered or missed it's running great!
To Michael and all the others who helped me work my way out of another trouble code a big Thank You my brothers. .
I got caught out with those drafted 5-point torx too.
The connector securing bolt on the dead XKR's ECM is another, as I found out trying with a 6-point from my toolset...
Last edited by michaelh; Sep 26, 2025 at 01:45 PM.
