97 Chev 1500 Express C.E.L. P0340 CMP problem

FAATmofo · 09-11-2008, 07:08 PM

I have a 1997 5.7L 1500 van I am trying to fix. I had originally pulled 4 codes out of this truck and 3 of them were O2 codes the last one was a P0340 Camshaft Position Sensor Problem. Replaced the O2 sensors and the CMP sensor, and I still had a p0340 code in the computer. When I looked at the data on my scan tool I found that the PCM was retarding the timing -45 degrees. I checked the installation of the sensor and the teeth on the distributor gear. All were fine so I got a new sensor just in case and then I checked voltage at the three wires to the CMP connector. All checked out fine and I was getting a signal. Still it was retarding timing. So I moved the distributor while the car was running and it didn't budge. Please help me out here...I don't know where to go with this.

Does anyone have the wire color, pin number and connector number of the Camshaft Position Sensor at the PCM?
Or any other ideas here?!!

mudseeker · 09-11-2008, 07:59 PM

see if this helps you any.
OBD-II Trouble Code: P0340 Camshaft Position Sensor Circuit Malfunction

Case 7230 · 09-12-2008, 06:53 AM

A friend of mine had the same type of trouble with a small Japanese car. His scan tool kept telling him a defective cam position sensor, even when he fitted a new one. The problem turned out to be a worn timing chain. Just a thought. Good luck.

FAATmofo · 09-12-2008, 08:13 AM

I can understand the timing chain issue but even when I turn the distributor manually while the engine is running, I get no change in timing.

mudseeker · 09-12-2008, 10:27 AM

the timing is controlled by the computer, turning the dizzy will not effect it.

09-11-2008, 07:08 PM	#1
FAATmofo Junior Member Join Date: Sep 2008 Posts: 2	97 Chev 1500 Express C.E.L. P0340 CMP problem I have a 1997 5.7L 1500 van I am trying to fix. I had originally pulled 4 codes out of this truck and 3 of them were O2 codes the last one was a P0340 Camshaft Position Sensor Problem. Replaced the O2 sensors and the CMP sensor, and I still had a p0340 code in the computer. When I looked at the data on my scan tool I found that the PCM was retarding the timing -45 degrees. I checked the installation of the sensor and the teeth on the distributor gear. All were fine so I got a new sensor just in case and then I checked voltage at the three wires to the CMP connector. All checked out fine and I was getting a signal. Still it was retarding timing. So I moved the distributor while the car was running and it didn't budge. Please help me out here...I don't know where to go with this. Does anyone have the wire color, pin number and connector number of the Camshaft Position Sensor at the PCM? Or any other ideas here?!!

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09-11-2008, 07:59 PM	#2
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	see if this helps you any. OBD-II Trouble Code: P0340 Camshaft Position Sensor Circuit Malfunction

09-12-2008, 06:53 AM	#3
Case 7230 Senior Member Join Date: Dec 2007 Posts: 547	A friend of mine had the same type of trouble with a small Japanese car. His scan tool kept telling him a defective cam position sensor, even when he fitted a new one. The problem turned out to be a worn timing chain. Just a thought. Good luck.

09-12-2008, 08:13 AM	#4
FAATmofo Junior Member Join Date: Sep 2008 Posts: 2	I can understand the timing chain issue but even when I turn the distributor manually while the engine is running, I get no change in timing.

09-12-2008, 10:27 AM	#5
mudseeker Senior Moderator Join Date: Feb 2006 Location: michigan Posts: 6,375	the timing is controlled by the computer, turning the dizzy will not effect it.