C1791: Left Rear Air Spring Solenoid Open
The air suspension control module has detected an open circuit in the left rear air spring solenoid output. This means the module does not see the expected current when it tries to activate the solenoid, preventing height adjustment at that corner.
1. Commonly Affected Makes
2. Most Common Causes
- Left rear air spring solenoid with an internally open coil
- Cut or disconnected signal or ground wire in the solenoid circuit
- Damaged, corroded, or loose terminals at the solenoid or module connector
- Internal failure of the output driver in the suspension control module
3. Symptoms You Will Notice
- Vehicle leans or sits lower on the left rear side
- Suspension warning light illuminated on the dashboard
4. Step-by-Step Diagnosis
Check for diagnostic trouble codes and verify C1791 is present
Inspect the left rear air spring solenoid connector for corrosion, damage, or loose pins
Measure resistance across the solenoid coil; an open circuit (infinite resistance) indicates a faulty solenoid
Check continuity of the wiring between the solenoid and the suspension control module
If wiring and solenoid are good, suspect a failed module output driver
5. Frequently Asked Questions
Is it safe to drive?▼
Driving is possible but not recommended for long distances. The vehicle may sag on one side, affecting handling and ride comfort. Have it repaired soon to avoid additional suspension wear.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on whether the solenoid, wiring, or module needs replacement. Labor and parts vary by vehicle make and model.