Electronic Ignition Timing Retard (LSi)

On LSi, 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 retard circuit, a Code 52 will set in ECM memory. If a code is set, see TESTS W/CODES article in this section.