Trying to bring a 2001 xk8 back to life
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From: Mo
There are 3 lights under the speedo, center and right ones stay on all the time when key is on, no flashing
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From: Spain
Hey everyone, here's an update
After some recommendations to hunt down the tps issues/codes found that the input to the ecm from it is sending no voltage. None at all. Connecter em81. Thoughts?
I'm stupid, have to back probe lol was thinking its input so can unplug, nope. Here's what I'm getting
All on connector em81
9 - idle .58 full throttle 3.15v
10 .86 idle to full throttle no change
18 idle .58 full throttle 3.15
19 1.6v no matter imput
10 and 19 are supposed to be moving and are not.
The others are close but not at spec
After some recommendations to hunt down the tps issues/codes found that the input to the ecm from it is sending no voltage. None at all. Connecter em81. Thoughts?
I'm stupid, have to back probe lol was thinking its input so can unplug, nope. Here's what I'm getting
All on connector em81
9 - idle .58 full throttle 3.15v
10 .86 idle to full throttle no change
18 idle .58 full throttle 3.15
19 1.6v no matter imput
10 and 19 are supposed to be moving and are not.
The others are close but not at spec
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Junior Member
Joined: Sep 2025
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From: Mo
So your pedal position sensor outputs are more or less correct, your throttle position sensor outputs are doing nothing. If your engine isn't running and the throttle butterfly isn't moving, the TPS output isn't going to change. Maybe remove the TPS from the throttle body (mark the position first) and move the sensor by hand to see if the values change.
I will do that. Butterfly does move according to pedal imput very well
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From: Spain
If you have a scanner like Torque you can see the live data for those values as well.
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From: Mo
Another interesting update, now when I try to crank it over it will once, soon as I let the key return run position, It blocks me from cranking. Then if I turn key off and back on it will let me crank one time again. I'm wondering if we should look more into theft system. Which light is the theft light? Does anyone know what pins send that theft signal into the ecm?
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From: Jersey, Channel Islands
That is normal behaviour. Probably to prevent an attempt to crank when the engine is running.
The security system is a data dialogue between the key (the chip it contains), the ECM, and the BPM. If that was failing, I'd expect no crank and a P1260 DTC to be thrown.
Sorry I can't give a fuller answer atm as I'm on a mobile.
Last edited by michaelh; Oct 5, 2025 at 12:50 AM.
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From: Spain
Throttle Position Sensor as a percentage is a standard PID, so you should at least be able to see that in Torque. The actual values for the two tracks on the TPS sensor and PPS sensor are also available, but Torque might not be able to show that as standard (you have to add custom PIDs). You can also see all of this in IDS if you have it in the datalogger (live data). Maybe your next project should be to install IDS on an old laptop.
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From: Mo
That is normal behaviour. Probably to prevent an attempt to crank when the engine is running.
If the car cranks, then the immobiliser is happy.
The security system is a data dialogue between the key (the chip it contains), the ECM, and the BPM. If that was failing, I'd expect no crank and a P1260 DTC to be thrown.
Sorry I can't give a fuller answer atm as I'm on a mobile.
If the car cranks, then the immobiliser is happy.
The security system is a data dialogue between the key (the chip it contains), the ECM, and the BPM. If that was failing, I'd expect no crank and a P1260 DTC to be thrown.
Sorry I can't give a fuller answer atm as I'm on a mobile.
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