Dual Knock Sensor System

DTC 43 Dual KNOCK SENSOR SYSTEM
(PCM - Automatic Transmission)

DTC 43 Chart (Dual Knock Sensor):

Dual Knock Sensor Circuit:

Circuit Description:
The DTC 43 circuit consists of two knock sensors with one wire that is spliced together and goes directly to the PCM. There is one DTC 43 check performed by the PCM. The check consists of monitoring CKT 496 for a voltage that is above .63 volt and below 3 volts.

DTC 43 Will Set When: If voltage is either too high or too low, for 10 seconds, DTC 43 will set.

Action Taken (PCM will default to): The PCM will turn "ON" the MIL (Malfunction Indicator Lamp).

DTC 43 Will Clear When: Conditions for fault are no longer present and Tech 1 "clear DTCs" function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and ECM B fuse is removed for 10 seconds.

DTC Chart Test Description: Number(s) below refer to circled number(s) on the diagnostic chart.

1. If an audible knock is heard from the engine, repair the internal engine problem as normally no knock should be detected at idle.
The PCM applies 5 volts on CKT 496 which should be present at the knock sensor terminals when the sensors are disconnected.

2. This test determines if the wiring or if the KS portion of the PROM (MEM-CAL) is faulty.

3. An improperly installed knock sensor can prevent the knock sensor from grounding to the block.

Diagnostic Aids: Check CKT 496 for a potential open or short to ground.

Also, check for proper installation of PROM (MEM-CAL).

Refer to DIAGNOSIS BY SYMPTOM/ INTERMITTENTS - Intermittent Malfunctions.