DTC 66 - Adjuster Assembly Control Fault: Notes

Fig 1: Adjuster Assembly Control System Schematic

Courtesy of GENERAL MOTORS CORP.

Adjuster assembly circuit provides power and ground to adjuster assembly during TCS operation to help control engine torque.

DTC 66 will set if during TCS operation, EBTCM delivers more than 18 amps to adjuster assembly for more than 3 seconds without adjuster assembly reaching its desired position.

Fig 2: DTC 66 Diagnostic Flow Chart

Courtesy of GENERAL MOTORS CORP.

1. Checks if DTC 65 is set since DTC 65 conditions can affect DTC 66.
2. Checks for mechanical binding of adjuster assembly, attached cables, and components that are attached to cables, which can cause excessive load on adjuster assembly.
3. Since DTC 66 only sets during TCS operation, this step raises vehicle on hoist so rear wheels will spin and fronts will not. This induces system into attempting TCS control. Throttle angle must be 15-50 percent and system must attempt TCS control for more than 3 seconds. This ensures that DTC setting throttle and timing parameters are met when checking for DTC 66 reset.