P0342 code ?'s
Teching In
Joined: Jun 2022
Posts: 9
Likes: 0
I'm dealing with a similar issue. Which connector do you need to swap the pins on, the connector that plugs into the cam sensor or the jumper harness by the cyl head. I have a red jumper harness by the driver side of the fuel rail. I've been told that it was a injector diagnostic harness but not entirely sure. I have a 01 firebird but it has a iron 408 stroker and the harness isn't original to the 01 v6 firebird.. I didn't build the car originally. Just rebuilt the motor over the winter and its been weeks and i cant get past this cam sensor code. Feel free to reach out via personal message
Launching!
Joined: Apr 2015
Posts: 200
Likes: 2
Low voltage cam position sensor Code P0342 in 98 5.7, other years similar. The PCM uses the cam sensor to determine firing order on start-up, without good signal the PCM reverts switching firing order back and forth between 180* out and right while watching the MAF sensor. When it sees the MAF signal pick up sharply it sees "engine started" and leaves the firing order there until the next shut down. For some reason the PCM is not processing a good camshaft position sensor (CMP) signal. This could be caused by serveral things.
Defective sensor (not likely now with new one but still possible)
sensor 3 wire circuit missing power or ground from PCM
wiring problems (open, shorts, poor connections)
defective PCM (circuit works computer doesn't)
engine mechanical problem (camshaft or engine wear, wrong cam like for a LS2 where the sensor is in front)
Before I spend a lot more time descibing the wiring and diagnostics do you have a DVOM and a basic knowledge on how to use one? Can you test for voltage, OHMS, continuity, duty cycle, etc? Well hopefully so because I ended up typing it out anyways. If not find someone who does or take it too a pro before you break something lol. Have fun, this is what I do for a living. Hopefully you can understand it and it helps you find the problem. Not responsible for damages. Always disconnect your battery before diconnecting PCM from harness.
First off was the bottom of the old sensor physically scraped, bent, or otherwise wacked on? If it was pull you new one and check to see if it's now busted up also. If so you have internal engine problems that are taking out the sensor by contact. If not you should pull the connector off the sensor and look at the terminals carefully. Look for a loose fitting, bent open, or missing terminal. There is a jumper or splice for this circuit on this car near the EGR valve, open it and check both sides of the splice connector just the same. If it's already unplugged there's the problem.
There are three wires in this circuit. Tests for voltage, grounds, and signal are all with the key on. Corrosion in any conector or along any wire is a give away as to a problem and should be corrected or repaired first.
RED is BATV+ from the PCM, with the jumper splice reconnected you should have BATV+ at the red wire terminal in the CMP connector when grounding the DVOM on the battery ground terminal.
PINK/BLACk is the ground for the sensor, it grounds in the PCM. You should be able to see the same voltage as testing above but using this terminal to ground your DVOM.
If either or both fail this test pull the PCM and disconnect the wire harness and check these circuits for continuity. Look at all the pins and make sure they are all there and straight. If the circuits are all sound from PCM to sensor connectors and you don't have one or both voltage and ground then it's a bad PCM.
If both are good you can tap into the circuits signal return wire BROWN/WHITE with your DVOM (anywhere along the circuit but near the PCM connector is best) with your DVOM grounded to BAT- check DC voltage duty cycle with all reconnected and the engine running at idle it should be 45% to 55%.
If no signal and power and ground are still good check for continuity from the CMP sensor connector back to your tap. If no continuity find and repair the open circut. If signal is good then check for continuity from the PCM connector pin to your tap. If no continuity find and repair the open circut.
If all is good in the circuit with a bad or missing signal you have a defective sensor or internal engine problems that prevent the sensor from generating a good signal, like wrong or bad cam, i/e missing reluctor (trigger) wheel, out of place (timing gear walked forward), or similar.
If you do have a proper 45-55% duty cycle on this circuit pull the PCM and check the signal return circuit BROWN/WHITE pin for damage or missing, then check for continuity from the PCM connector to the CMP sensor connector. If you had a good duty cycle signal and the wiring is all good from connector to connector you have a defective PCM.
Internal engine mechanical problems can be verified by removing the CMP sensor and looking down the hole, perferably with a boreascope but possible with a mirror and light. Crank the engine while looking, you should see undamaged metal passing the hole 50% of the time. If more or less it's mechanical.
Vernon
Defective sensor (not likely now with new one but still possible)
sensor 3 wire circuit missing power or ground from PCM
wiring problems (open, shorts, poor connections)
defective PCM (circuit works computer doesn't)
engine mechanical problem (camshaft or engine wear, wrong cam like for a LS2 where the sensor is in front)
Before I spend a lot more time descibing the wiring and diagnostics do you have a DVOM and a basic knowledge on how to use one? Can you test for voltage, OHMS, continuity, duty cycle, etc? Well hopefully so because I ended up typing it out anyways. If not find someone who does or take it too a pro before you break something lol. Have fun, this is what I do for a living. Hopefully you can understand it and it helps you find the problem. Not responsible for damages. Always disconnect your battery before diconnecting PCM from harness.
First off was the bottom of the old sensor physically scraped, bent, or otherwise wacked on? If it was pull you new one and check to see if it's now busted up also. If so you have internal engine problems that are taking out the sensor by contact. If not you should pull the connector off the sensor and look at the terminals carefully. Look for a loose fitting, bent open, or missing terminal. There is a jumper or splice for this circuit on this car near the EGR valve, open it and check both sides of the splice connector just the same. If it's already unplugged there's the problem.
There are three wires in this circuit. Tests for voltage, grounds, and signal are all with the key on. Corrosion in any conector or along any wire is a give away as to a problem and should be corrected or repaired first.
RED is BATV+ from the PCM, with the jumper splice reconnected you should have BATV+ at the red wire terminal in the CMP connector when grounding the DVOM on the battery ground terminal.
PINK/BLACk is the ground for the sensor, it grounds in the PCM. You should be able to see the same voltage as testing above but using this terminal to ground your DVOM.
If either or both fail this test pull the PCM and disconnect the wire harness and check these circuits for continuity. Look at all the pins and make sure they are all there and straight. If the circuits are all sound from PCM to sensor connectors and you don't have one or both voltage and ground then it's a bad PCM.
If both are good you can tap into the circuits signal return wire BROWN/WHITE with your DVOM (anywhere along the circuit but near the PCM connector is best) with your DVOM grounded to BAT- check DC voltage duty cycle with all reconnected and the engine running at idle it should be 45% to 55%.
If no signal and power and ground are still good check for continuity from the CMP sensor connector back to your tap. If no continuity find and repair the open circut. If signal is good then check for continuity from the PCM connector pin to your tap. If no continuity find and repair the open circut.
If all is good in the circuit with a bad or missing signal you have a defective sensor or internal engine problems that prevent the sensor from generating a good signal, like wrong or bad cam, i/e missing reluctor (trigger) wheel, out of place (timing gear walked forward), or similar.
If you do have a proper 45-55% duty cycle on this circuit pull the PCM and check the signal return circuit BROWN/WHITE pin for damage or missing, then check for continuity from the PCM connector to the CMP sensor connector. If you had a good duty cycle signal and the wiring is all good from connector to connector you have a defective PCM.
Internal engine mechanical problems can be verified by removing the CMP sensor and looking down the hole, perferably with a boreascope but possible with a mirror and light. Crank the engine while looking, you should see undamaged metal passing the hole 50% of the time. If more or less it's mechanical.
Vernon
