C0388 Buick Code - Rear Differential Lock Actuator
Quick Answer
The rear differential control circuit consists of a actuator (coil) which engages and disengages the rear axle differential lock. Common causes include Faulty Rear Differential Lock Actuator, Rear Differential Lock Actuator harness is open or shorted, Rear Differential Lock Actuator circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C0388 Buick indicates Rear Differential Lock Actuator.
- Common causes
- Common causes include Faulty Rear Differential Lock Actuator, Rear Differential Lock Actuator harness is open or shorted, Rear Differential Lock Actuator circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code C0388 Buick Description
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.
What are the Possible Causes of the DTC C0388 Buick?
- Faulty Rear Differential Lock Actuator
- Rear Differential Lock Actuator harness is open or shorted
- Rear Differential Lock Actuator circuit poor electrical connection
How to Fix the DTC C0388 Buick?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the C0388 Buick code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about C0388 Buick Code
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