OBD Guide

C1866

Air Suspension Rear Inflator Solenoid Output Circuit Open

C1866 is an OBD-II diagnostic trouble code meaning: Air Suspension Rear Inflator Solenoid Output Circuit Open. Common causes: open or short circuit in solenoid wiring harness, supercharger solenoid valve malfunction. Estimated repair cost: $111–389.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$111–389 (est.)

Symptoms

  • Uneven body height (the rear end sags or is not adjustable)
  • Air suspension error message on the instrument panel
  • Automatic rear suspension adjustment does not work
  • Hard rear suspension

Causes

  • Open or short circuit in solenoid wiring harness
  • Supercharger solenoid valve malfunction
  • Oxidation or damage to electrical contacts
  • Air suspension control module malfunction
  • Damage to wiring due to corrosion or mechanical stress

How to Fix

  1. Check the supply voltage and continuity of the solenoid circuit
  2. Inspect the wiring harness for damage
  3. Check solenoid resistance (usually 10-30 ohms)
  4. Clean the connector contacts
  5. If necessary, replace the solenoid or repair the wiring harness.
  6. Reset the error and test the system

Related codes

FAQ

What does the C1866 code mean?

C1866 is an OBD-II diagnostic trouble code that indicates: Air Suspension Rear Inflator Solenoid Output Circuit Open

What causes a C1866 error code?

The most common causes of C1866 include: Open or short circuit in solenoid wiring harness; Supercharger solenoid valve malfunction; Oxidation or damage to electrical contacts; Air suspension control module malfunction.

How do I fix a C1866 diagnostic trouble code?

To fix C1866: Check the supply voltage and continuity of the solenoid circuit. Inspect the wiring harness for damage. Check solenoid resistance (usually 10-30 ohms). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1866?

Limited driving only, diagnose soon

How much does it cost to fix C1866?

The estimated repair cost for C1866 is $111–389. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat