What Does C0660 Mean?
This code indicates the suspension control module has detected an electrical fault in the air suspension exhaust valve solenoid circuit. The exhaust valve is responsible for releasing air from the air springs to lower the vehicle or adjust ride height. The module detected an open circuit, short to ground, short to power, or excessive resistance in the valve's control circuit preventing proper operation.
Common Causes
45%
Faulty air suspension exhaust valve solenoid with internal open circuit or short
30%
Damaged wiring harness or corroded connector at exhaust valve with broken wires or terminal corrosion
15%
Short to ground or power in valve control circuit wiring due to chafing or damage
10%
Failed suspension control module with internal driver circuit failure
Diagnostic Steps
1
Step 1: Perform visual inspection of exhaust valve solenoid, connector, and wiring harness for obvious damage, corrosion, moisture intrusion, or loose connections. Check connector pins for bent, pushed back, or corroded terminals.
2
Step 2: With ignition off, disconnect exhaust valve connector and measure solenoid resistance across valve terminals using digital multimeter. Typical specification is 3-10 ohms; reading of infinite resistance indicates open coil, zero ohms indicates short.
3
Step 3: Backprobe or measure voltage at valve harness connector with ignition on. Check for battery voltage on power supply wire and ground continuity on ground circuit. Verify control signal wire shows proper switching voltage when commanded by module (typically 0V off, 12V on).
4
Step 4: If wiring and power/ground are good but valve resistance is out of specification, replace exhaust valve solenoid. If valve tests good, check for short to ground or power in control circuit wiring by measuring resistance between control wire and ground/power with harness disconnected at both ends (should read infinite resistance).
5
Step 5: After repairs, clear codes, command exhaust valve operation using scan tool active tests, and verify proper air release function. Monitor for code recurrence and verify suspension height adjustment operates correctly.
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
This code indicates the suspension control module has detected an electrical fault in the air suspension exhaust valve solenoid circuit. The exhaust valve is responsible for releasing air from the air springs to lower the vehicle or adjust ride height. The module detected an open circuit, short to g...
The most common cause of C0660 (Level Control Exhaust Valve Circuit Malfunction) is: Faulty air suspension exhaust valve solenoid with internal open circuit or short
Typical repair costs for C0660 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive but air suspension height adjustment will be impaired, potentially causing ride height issues or suspension remaining in raised position. Vehicle may experience handling differences and reduced ride quality until repaired.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C0660 to identify the root cause.
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Quick Info
Category
Chassis
System
Suspension System (Air Suspension/Level Control)
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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