C 1500 Truck 2WD V8-350 5.7L VIN K TBI (1995)
Knock Sensor Module: Description and Operation
Knock Sensor Circuit
DESCRIPTION AND OPERATION:
The Knock Sensor (KS) system has a module that sends a voltage signal to the ECM. As the KS detects detonation, the voltage from the KS
module to the ECM will drop. This signal allows the ECM to retard timing. The ECM will retard the timing when knock is detected and rpm is
above 900 rpm. Diagnostic Trouble Code (DTC) 43 will set when the ECM has detected low voltage at CKT 457 on terminal "B7" for longer than
5 seconds with the engine operating or when the system has failed the functional check. The ECM continually monitors voltage on CKT 457 on
terminal "B7."
The ECM will advance the spark timing when:
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Engine coolant temperature is above 95°C.
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Engine is under heavy load (near WOT).
