Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
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Do you a scanner that can view the knock sensor data?
What is the code number?
Have you torqued these sensor or just put them in? They need to be torqued to 15 lbft. a loose or tight sensor can cause this code.
The best way to verify is with a scanner. There are only a few suspects on this system.
The PCM may have only the one symptom. The best way to verify is with a scanner and a volt meter.
What brand are the knock sensors? I am looking for a test procedure for you and see a huge problem with the aftermarket sensors. I only use Delco and have had a defective ones before.
There is a GM bulletin on these. replacing the sensors and harness. Send me your VIN and I can tell you if there was a calibration change for the PCM to address this
There is not an update for the PCM for this problem. It does have an update for an O2 code.
The resistance of the knock sensor should be 93K-107K ohm with key off.
To test place the meter in the 400 mv AC HZ scale. tap engine near sensor and observe readings.
The PCM monitors the AC HZ transmitted by the sensors.
You can check at the PCM Sensor 2 is a lt blu wire in Connector 1 pin 17
If the PCM is getting the reading then I would suspect PCM
The PCM Should not get a reading with the engine off. The O2 update is for a PCM calibration update. Since you are not having this concern I would not get the update yet. I just wanted you to be aware that there is a possible calibration update for your PCM.
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