Electronic Ignition Timing Retard (Prizm GSi)

On Prizm GSi, a knock sensor, located in rear of cylinder block, sends a variable AC voltage signal to ECM depending on engine detonation. ECM uses this signal to determine if ignition timing should be retarded. Testing information is not supplied by manufacturer. If a fault occurs in the retard circuit, a Code 52 or 53 will set in ECM memory. If a code is set, see G - TESTS W/ CODES article in this section.