2014 Caprice Sensor Woes
2014 Caprice Sensor Woes I've been trying to track down a P0651 5v reference circuit 2 DTC for awhile now and figured it's time to ask for help.
Looked up the sensors on this circuit and they're:
Accelerator position sensor 1
Brake booster vaccum sensor
Brake pedal position sensor
Crankshaft position sensor
Throttle position sensor 1 and 2
I've unplugged all of these and am still getting the P0651. I checked voltage at all the plugs and I'm getting a solid 5v. Is there another way to check the circuits/wiring?
Another thing that happened around the same time is my MAP is reading 13psi and oil pressure is reading 130 psi KOEO. They don't seem to be in circuit two but they're having problems. I unplugged them as well and still get the P0651.
Grounds near PCM, battery, front of pass cylinder head, and back of both cylinder heads all appear fine and OHM to 0.
Not too sure what to try next other than buying new sensors or cutting back heat shielding searching for a short to voltage or ground somewhere.
Looked up the sensors on this circuit and they're:
Accelerator position sensor 1
Brake booster vaccum sensor
Brake pedal position sensor
Crankshaft position sensor
Throttle position sensor 1 and 2
I've unplugged all of these and am still getting the P0651. I checked voltage at all the plugs and I'm getting a solid 5v. Is there another way to check the circuits/wiring?
Another thing that happened around the same time is my MAP is reading 13psi and oil pressure is reading 130 psi KOEO. They don't seem to be in circuit two but they're having problems. I unplugged them as well and still get the P0651.
Grounds near PCM, battery, front of pass cylinder head, and back of both cylinder heads all appear fine and OHM to 0.
Not too sure what to try next other than buying new sensors or cutting back heat shielding searching for a short to voltage or ground somewhere.
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From: Ann Arbor, MI
Wow, you certainly have checked a lot.
It seems unlikely that any one sensor is causing the problem, especially since you can read a "solid 5V" and you have disconnected some of the sensors.
What do they all have in common? The PCM. Well, also the harness.
Personally, I would run a ground from the battery to the PCM case, and possibly another wire from the battery to the harness wires at the PCM. If this solved it, then you can debug the harness and grounding.
Next I would order another PCM, assuming they are $150 or so on ebay. Opening a harness to search for wire problems could be an endless task.
Just my 2 cents. (3 with inflation)
It seems unlikely that any one sensor is causing the problem, especially since you can read a "solid 5V" and you have disconnected some of the sensors.
What do they all have in common? The PCM. Well, also the harness.
Personally, I would run a ground from the battery to the PCM case, and possibly another wire from the battery to the harness wires at the PCM. If this solved it, then you can debug the harness and grounding.
Next I would order another PCM, assuming they are $150 or so on ebay. Opening a harness to search for wire problems could be an endless task.
Just my 2 cents. (3 with inflation)
Wow, you certainly have checked a lot.
It seems unlikely that any one sensor is causing the problem, especially since you can read a "solid 5V" and you have disconnected some of the sensors.
What do they all have in common? The PCM. Well, also the harness.
Personally, I would run a ground from the battery to the PCM case, and possibly another wire from the battery to the harness wires at the PCM. If this solved it, then you can debug the harness and grounding.
Next I would order another PCM, assuming they are $150 or so on ebay. Opening a harness to search for wire problems could be an endless task.
Just my 2 cents. (3 with inflation)
It seems unlikely that any one sensor is causing the problem, especially since you can read a "solid 5V" and you have disconnected some of the sensors.
What do they all have in common? The PCM. Well, also the harness.
Personally, I would run a ground from the battery to the PCM case, and possibly another wire from the battery to the harness wires at the PCM. If this solved it, then you can debug the harness and grounding.
Next I would order another PCM, assuming they are $150 or so on ebay. Opening a harness to search for wire problems could be an endless task.
Just my 2 cents. (3 with inflation)
I have a spare E38 from a Tahoe. If the ground to PCM doesn't help I may throw it in and see how it does. Pulling apart the harness is the last thing I want to do so thank you for a couple ideas to keep hope alive.
Ran a jumper to connect battery negative to PCM case. Also checked ohm between battery ground connections, all good.
For the PCM, can I just plug the Tahoe one in without flashing it and check to see if sensors work with it?
For the PCM, can I just plug the Tahoe one in without flashing it and check to see if sensors work with it?
