Knock sensor ground
Thread Starter
4th Gear
Joined: Aug 2019
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Race Director
Joined: Apr 2007
Posts: 11,150
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From: South Western Ontario
Both the sensor element and the heater have negative wires and those wires are what passes the signal and power. However, the negative wire going to the sensor element should also be grounded to the sensor housing or else the PCM won't read the sensor correctly. Cheap off brand sensors have been known to be missing that connection. You can check it if you want to be sure. The sensor will have 4 wires. 2 the same color are the heater. The other 2 are the sensor element. The darker color wire is the positive and the lighter color wire is the negative. Check continuity between the negative wire and the sensor body.
