C0388 HUMMER – Rear Differential Lock Actuator

C0388 HUMMER Possible Symptoms

Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)

C0388 HUMMER Possible Causes

Faulty Rear Differential Lock Actuator,Rear Differential Lock Actuator harness is open or shorted,Rear Differential Lock Actuator circuit poor electrical connection

C0388 HUMMER Description

The rear differential control circuit consists of a actuator (coil) which engages and disengages the rear axle differential lock. The rear differential actuator consists of a coil assembly, and a locking assembly with springs and pins to lock the rear differential, all within the rear differential assembly. The rear axle differential lock actuator consists of the following circuits: – The rear differential lock control circuit, which is connected to the transfer case shift control module and supplies battery voltage. – The rear differential lock return (ground) circuit, which is also connected to the transfer case shift control module. Whenever the rear differential lock has been requested the transfer case shift control module provides battery voltage through the rear differential lock control circuit, and provides ground through the rear differential lock return circuit through a current limiting driver. Whenever a rear differential lock is requested the transfer case must be in 4 LO and the vehicle speed must be below 5 km/h (3 mph) for the request to be accepted. The rear differential lock will remain locked up to 32 km/h (20 mph) after which the rear differential lock will disengage. This DTC detects a short to ground, short-to-voltage, or an open circuit.