QuestionI recently bought this Concorde Limited, 3.5L HO engine, 80,000 miles. About 2 weeks after I got it, the CEL came on and after that if I pressed on the gas too hard the engine would cut out. I had the codes read and it said P0344. I drove the car a few more days, usually it was fine, but a couple more times it cut out one me, actually dieing once, so I replaced the camshaft position sensor.
The CEL went out and the car was fine for a few days. Now the CEL has come back on, however it runs fine so far. I had the codes read again at my friendly Autozone, now it has 3 codes! P0344 again, also P0340 and P0157. Is this more like a faulty connector or what? Thanks
AnswerHi Roland H.,
Lets take the codes one at a time. The 0157 says that the downstream oxygen sensor on the right side (located after the catalytic converter) has its signal shorted to ground. So I would suggest checking the wiring there and if it seems ok then disconnect the plug and see if the tan/white wire on pin 4 of the harness is indeed shorted to ground or if the pin on the other side of the connector is shorted to ground which would indicate a bad sensor proper.
On the cam shaft sensor codes: my suggestion would be to verify the wiring of that sensor and also do a voltage test on its signal.
The wiring is: black/light blue on pin 2 of the connector to pin 27 at the pcm,
tan/yellow on pin 3 to pin 34 of the pcm
violet/white on pin 1 to pin 29 of the pcm
Use an ohmmeter to verify conductivity between the pins listed, and that the wire is not conducting to chassis ground (althogh the pin 2 wire may show such a ground so ignore that one).
With the ignition switch on you should get 5V on pin 1. Then plug in the sensor and probe the other two wires with fine pins if nescessary to make contact. Then turn the engine over by hand using a socket on the crank pulley bolt and observe for whether the voltage reading pulses between 0.3 and 5.0V several times for each revolution of the crank. If so, then everything is OK. Otherwise, let me know. While you are making all the above tests/measurements try shaking gently on the harnesses to induce a disconnect or short, which you asked about.
It may also be the case that you didn't push the sensor tip (with papaer spacer attached) firmly against the surface of the cam sprocket and hold it there while tighten the mounting screw that holds it in place. So think about that as a possibility for an intermittency in the signal.
Roland
PS: Sorry for the delay in answering but I just received your question in the 'question pool' to which it had been referred by Kevin, who I had invited to share some of his backlog.
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