AutoCodes – GMC – C0655 GMC

C0655 GMC Code - Level Control Compressor Relay Malfunction

Quick Answer

The automatic level control adjusts the vehicle suspension ride height. Common causes include Faulty Level Control Compressor Relay, Level Control Compressor Relay harness is open or shorted, Level Control Compressor Relay 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: C0655 GMC indicates Level Control Compressor Relay Malfunction.
Common causes: Common causes include Faulty Level Control Compressor Relay, Level Control Compressor Relay harness is open or shorted, Level Control Compressor Relay 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.

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Code Popularity 1,631

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 31, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code C0655 GMC Description

The automatic level control adjusts the vehicle suspension ride height. The Rear Integration Module (RIM) determines the height of the vehicle based on the voltage from the automatic level control sensor. The RIM grounds the compressor relay and the exhaust control solenoid to raise and lower the vehicle in order to keep the vehicle level

OBDII Code C0655 GMC - Level Control Compressor Relay Malfunction - AutoCodes.com — C0655 GMC Code - Level Control Compressor Relay Malfunction

What does this mean?

What are the Possible Causes of the DTC C0655 GMC?

Faulty Level Control Compressor Relay
Level Control Compressor Relay harness is open or shorted
Level Control Compressor Relay circuit poor electrical connection

How to Fix the DTC C0655 GMC?

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 C0655 GMC 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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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about C0655 GMC Code

1. What does the OBDII code C0655 mean on a GMC?

The code C0655 indicates a "Level Control Compressor Relay Malfunction," meaning thereâ€™s an issue with the relay controlling the air suspension compressor.

2. What are the common symptoms of the C0655 code?

Common symptoms include the air suspension not adjusting properly, a sagging or uneven ride height, or the air compressor failing to activate.

3. What causes the C0655 code on a GMC vehicle?

Possible causes include a faulty level control compressor relay, damaged wiring or connectors, a blown fuse, or a malfunctioning air suspension compressor.

4. Can I drive my GMC with the C0655 code?

Yes, you can drive with this code, but it may result in an uncomfortable ride or uneven vehicle height, which could affect handling and tire wear.

5. How do I diagnose the C0655 code?

Start by checking the relay, fuses, and wiring for damage or corrosion. Use a scan tool to test the relay operation and inspect the air suspension system for leaks or malfunctions.

6. How do I fix the C0655 code on my GMC?

Repairs may include replacing the level control compressor relay, repairing damaged wiring, replacing a blown fuse, or addressing issues with the air suspension compressor.

7. How much does it cost to fix the C0655 code?

Repair costs depend on the specific issue but typically range from $50 to $200 for a relay replacement, while compressor repairs or replacements may cost significantly more.

8. Can a bad air suspension compressor cause the C0655 code?

Yes, a failing or seized air suspension compressor can overload the relay and trigger the C0655 code.

9. How can I prevent the C0655 code from recurring?

Regularly inspect the air suspension system for leaks, maintain electrical connections, and address any suspension issues promptly to avoid overloading the relay.

10. Do I need a professional mechanic to fix the C0655 code?

While some repairs, like replacing a fuse or relay, can be done by DIYers, diagnosing and fixing more complex issues like compressor failures or wiring problems may require a professional.