DTC 52

DTC 52 Diagnostic Chart:

Knock Sensor Circuit:

Circuit Description:
The knock sensor (KS), located in the rear of the engine block, is used to detect engine knock (abnormal vibration). When engine knock is present, the KS signals the powertrain control module (PCM) to retard ignition timing. The KS is constructed of a piezoelectric element which generates an AC voltage when it becomes deformed (vibration or engine knock detected). The KS sends this voltage signal back to the powertrain control module (PCM), which in turn retards the ignition timing. By reducing the ignition timing, the engine knock will no longer be detected.

DTC 52 will set if the following condition is met for at least 0.50 seconds:

^ Open or short in the KS circuit with engine speed between 1,200 and 6,000 rpm.

Test Description:
Numbers below refer to circled numbers on the diagnostic chart.

1. Checks KS for circuit for possible shorts.

2. Determines if KS is faulty, BLK wire is open/shorted or if the PCM is faulty.

Diagnostic Aids:
Make sure that there are no mechanical failures that are inducing engine knock.

An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation. Inspect hamess connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.