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Q: Knock sensor code

asked by on

Just a check engine light

My car has 148400 miles.
My car has an automatic transmission.

A: Hello. Knock sensors play a large roll in h...

Hello. Knock sensors play a large roll in how the PCM (powertrain control module) times the spark. If excessive knock is present from the combustion cycle, the knock sensor will retard timing and attempt to correct it. The opposite is also true, if the knock sensor detects low input values, it can speed up the timing. When you are receiving a warning light and code for the knock sensor, the computer is telling you the sensor is not computing true values. This can be due to the sensor being bad, the wiring for the sensor being bad, a poor connection, or at worst a faulty PCM. You will simply need to replace the sensor(s). If the sensor has been replaced and the error code is still present, you will want to check the wiring and the connections. Although the wiring and connections are less likely to fail than the sensor, it is possible. Start by replacing the sensor, there is a strong chance its to blame, and check the wiring if that doesn’t solve the problem.

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