Service Engine Light 98 chevy Lumina

09-15-2007, 07:33 PM
My 98 chevy luminas service engine light came on after I got gas. I put vaseline around the threads to seal it and the light went out for 2 days and then came on again. I bought a new cap and the same thing happened, two days light out than back on. I took the car to Autozone and did a diagnostics test which came back with error message P0341, then took it a mechanic who ran his on diagnostics on it and he says the camshaft sensor needs changed. It is a semi expensive job for an older car and I want to be sure that that is the problem, plus the gas cap thing has me confused. any help would be appreciated. Thanks in advance.

09-16-2007, 02:13 AM
PO341 is camshaft sensor range incorrect, yes. If there were no codes for the evap emissions system, the gas cap had nothing to do with the CEL.

Blue Bowtie
09-21-2007, 06:43 AM
Another thing to remember is that the PCM is only reporting what it is detecting. The trouble code P0341 is not defined as "CMP Needs to be Replaced." Someone is perhaps misinterpreting the data. Instead, the code is described as "Camshaft Position Sensor Range or Performance Malfunction." All the PCM can detect is that the signal is not consistent. That can be caused by several things including, but not limited to, the CMP sensor. If you trust that your mechanic has already performed a complete diagnosis and has correctly determined that the sensor itself is the problem, then you can confidently authorize the repair. If, however, you suspect that the signal has not been tested directly at the sensor, the wire harness has not been inspected, and that the CMP sensor is receiving correct supply voltage and ground, I can understand your hesitation.

Actually, replacing the CMP is not that difficult on a 3.1/3.4 V-6. The accessories are in the way, and may have to be removed, but the work is not difficult. The other problem is that the camshaft itself can also have an influence on signal generation, since the "target" for the sensor is on the camshaft front journal. Contamination of the sensor is frequently a problem, and simply cleaning it can sometimes restore sensor performance. A camshaft which is "walking" in the block due to a worn thrust plate or cam sprocket can also affect signal. A worn timing chain can affect signal consistency (performance).

If the sensor has been tested and is failing electrically, however, there is little to do but replace it.

09-24-2007, 06:07 AM
I agree with Blue. The serp belt and power steering pump will have to be removed, then the CMPS is right there (on the 3100). One bolt securing it to the engine block and a wiring harness. If your car has the 3800, the CMPS is in the timing cover (relatively simple to change) but it could also be the interrupter magnet in the cam gear that is causing this code. Replacing it requires the timing cover and cam gear to be removed from the engine, which is a major repair.

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