What should the low reference voltage be for the Camshaft position sensor...
Thread Starter
On The Tree
Joined: Dec 2011
Posts: 186
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From: Philadelphia Area
What should the low reference voltage be for the Camshaft position sensor... and coolant temp sensor? Car is my 05 CTS-V/LS6
I'm getting a P0118 and P0342 and neither is because of faulty sensors, bad connectors or a bad PCM. I have proper voltage to the Cam sensor, but I would like to test the reference voltage for both. When should this voltage be present? ECT I would imagine all the time, but the CMP I'm thinking perhaps just while cranking? I didn't have any voltage on the reference when I checked the CMP plug with the key on the first time around but I assumed it was a ground. Now that I found the wiring diagrams online I know otherwise.
If anyone is curious my problem began many many months ago as a very infrequent P0341 (high signal from the cam sensor). And progressed to a constant P0341/P0342 (high/low signal) with occasional hard starting (crank sensor only start). After I replaced the CMP sensor I immediately had a P0342 and a P0118 with my PCM reading the temp sensor at -38. My tuner thought it was a bad PCM, I replaced it, no changes.
I removed the newly installed CMP sensor and tested it and old sensor with my Fluke meter. Both showed all the same #'s so I reinstalled the old sensor. This changed nothing. On the PCM pin out the CMP and ECT sensor signal wires are next to each other so I ran new a signal wire for the ECT as a test. No change.
When I clear the codes and my coolant temp sensor will read temperature for 15 seconds before going out again and turning my radiator fans on full blast.
I'm not a wiring guy but I have figured out mystery problems before, it just takes time. I would like to get this fixed this week because I have a long drive over the holiday weekend.
I'm getting a P0118 and P0342 and neither is because of faulty sensors, bad connectors or a bad PCM. I have proper voltage to the Cam sensor, but I would like to test the reference voltage for both. When should this voltage be present? ECT I would imagine all the time, but the CMP I'm thinking perhaps just while cranking? I didn't have any voltage on the reference when I checked the CMP plug with the key on the first time around but I assumed it was a ground. Now that I found the wiring diagrams online I know otherwise.
If anyone is curious my problem began many many months ago as a very infrequent P0341 (high signal from the cam sensor). And progressed to a constant P0341/P0342 (high/low signal) with occasional hard starting (crank sensor only start). After I replaced the CMP sensor I immediately had a P0342 and a P0118 with my PCM reading the temp sensor at -38. My tuner thought it was a bad PCM, I replaced it, no changes.
I removed the newly installed CMP sensor and tested it and old sensor with my Fluke meter. Both showed all the same #'s so I reinstalled the old sensor. This changed nothing. On the PCM pin out the CMP and ECT sensor signal wires are next to each other so I ran new a signal wire for the ECT as a test. No change.
When I clear the codes and my coolant temp sensor will read temperature for 15 seconds before going out again and turning my radiator fans on full blast.
I'm not a wiring guy but I have figured out mystery problems before, it just takes time. I would like to get this fixed this week because I have a long drive over the holiday weekend.
Thread Starter
On The Tree
Joined: Dec 2011
Posts: 186
Likes: 0
From: Philadelphia Area
Ran a new low reference wire from the pcm to the coolant temp sensor. Made no difference. The temp sensor code is for high voltage, this causes the temp sensor to falsely read high and thus the PCM stops taking the reading because it knows the reading is incorrect.
I don't understand what could cause this, the diagram shows the wires going directly to from the sensor to the PCM. The PCM is not the problem, the sensor is the not the problem, the wires are not the problem.
I don't understand what could cause this, the diagram shows the wires going directly to from the sensor to the PCM. The PCM is not the problem, the sensor is the not the problem, the wires are not the problem.
A high voltage DTC is caused by a unplugged sensor or an open circuit. The open circuit is usually caused by a broken wire, cracked or damaged sensor or loose connection.
Fot this kind of intermittent faults I replace the wiring from the pcm to the sensor including a new sensor connector. I have had many bad connectors I've lost count. You check them with a multimeter and they seem to be fine but they aren't.
If this don't fix the issue, then change the sensor
Fot this kind of intermittent faults I replace the wiring from the pcm to the sensor including a new sensor connector. I have had many bad connectors I've lost count. You check them with a multimeter and they seem to be fine but they aren't.
If this don't fix the issue, then change the sensor
Thread Starter
On The Tree
Joined: Dec 2011
Posts: 186
Likes: 0
From: Philadelphia Area
Thank you montecarlo, I just saw your post, I fixed the car last night. Two new wires to the ETC and 1 new signal wire to the CMP. Runs great now.
My guess as to the cause of the problem was power steering fluid running down the wire loom into a separation where the ETC sensor wires T off. The fluid degraded the insulation causing my issues.
My guess as to the cause of the problem was power steering fluid running down the wire loom into a separation where the ETC sensor wires T off. The fluid degraded the insulation causing my issues.
Teching In
Joined: Apr 2024
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What is ETC and CMP excuse my ignorance.t The center wire on my crankshaft position sensor is reading as a ground. I believe I need to rewire it.
Thank you montecarlo, I just saw your post, I fixed the car last night. Two new wires to the ETC and 1 new signal wire to the CMP. Runs great now.
My guess as to the cause of the problem was power steering fluid running down the wire loom into a separation where the ETC sensor wires T off. The fluid degraded the insulation causing my issues.
My guess as to the cause of the problem was power steering fluid running down the wire loom into a separation where the ETC sensor wires T off. The fluid degraded the insulation causing my issues.
