Ford Mustang 1989-1993 Repair Guide

Knock Sensor (KS)



The Knock Sensor (KS) is located in the engine block or cylinder head. As the detonation vibrations increase, the sensor signals to the Engine Control Module (ECM) to retard the timing to reduce knock.


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Fig. Fig. 1: KS circuit

  1. With ignition ON and engine OFF , measure voltage between KS connector terminals. If voltage reading is 2.4-2.6V, the circuit between the ECM and KS is okay.
  3. With engine running at idle and then at 3000 rpm, measure voltage using a DVOM on the AC setting between the KS terminals. If the AC voltage reading increases as the rpm increases, the sensor is okay.