OBD Guide
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C1791

Air Suspension Left Rear Air Spring/Shock Solenoid Output Circuit Open

C1791 is an OBD-II diagnostic trouble code meaning: Air Suspension Left Rear Air Spring/Shock Solenoid Output Circuit Open. Common causes: broken or damaged wiring harness to the solenoid, malfunction of the solenoid valve (solenoid). Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$56–167 (est.)

Symptoms

  • Uneven vehicle landing (sagging left rear corner)
  • Suspension error message on dashboard
  • Unstable operation of the air suspension
  • Increased suspension stiffness on one side

Causes

  • Broken or damaged wiring harness to the solenoid
  • Malfunction of the solenoid valve (solenoid)
  • Corrosion or poor contact in connectors
  • Air suspension control module malfunction
  • Mechanical damage to suspension components

How to Fix

  1. Visually inspect the wiring harness and connectors for damage
  2. Checking the continuity of the solenoid circuit with a multimeter
  3. Solenoid Resistance Testing
  4. Checking power and ground in the control circuit
  5. Replacing damaged wires or connectors
  6. Replacing a faulty solenoid if necessary
  7. Resetting the error and checking the system operation

Related codes

C1790C1792C1793C1794

FAQ

What does the C1791 code mean?

C1791 is an OBD-II diagnostic trouble code that indicates: Air Suspension Left Rear Air Spring/Shock Solenoid Output Circuit Open

What causes a C1791 error code?

The most common causes of C1791 include: Broken or damaged wiring harness to the solenoid; Malfunction of the solenoid valve (solenoid); Corrosion or poor contact in connectors; Air suspension control module malfunction.

How do I fix a C1791 diagnostic trouble code?

To fix C1791: Visually inspect the wiring harness and connectors for damage. Checking the continuity of the solenoid circuit with a multimeter. Solenoid Resistance Testing. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1791?

Limited driving only, diagnose soon

How much does it cost to fix C1791?

The estimated repair cost for C1791 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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