OBD Guide

C1991

Plant Ride Height Setting And/Or Tests Incomplete

C1991 is an OBD-II diagnostic trouble code meaning: Plant Ride Height Setting And/Or Tests Incomplete. Common causes: incomplete clearance calibration, malfunction of suspension level sensors. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–167 (est.)

Symptoms

  • Incorrect vehicle clearance
  • Error message on the dashboard
  • Unstable operation of the air suspension

Causes

  • Incomplete clearance calibration
  • Malfunction of suspension level sensors
  • Air suspension compressor problems
  • Malfunctions in the electronic suspension control unit
  • Broken or damaged wiring harnesses

How to Fix

  1. Check the condition of the suspension level sensors
  2. Check the operation of the air suspension compressor
  3. Carry out diagnostics of the electronic suspension control unit
  4. Calibrate clearance using diagnostic equipment
  5. Check the integrity of the wiring harnesses

Related codes

FAQ

What does the C1991 code mean?

C1991 is an OBD-II diagnostic trouble code that indicates: Plant Ride Height Setting And/Or Tests Incomplete

What causes a C1991 error code?

The most common causes of C1991 include: Incomplete clearance calibration; Malfunction of suspension level sensors; Air suspension compressor problems; Malfunctions in the electronic suspension control unit.

How do I fix a C1991 diagnostic trouble code?

To fix C1991: Check the condition of the suspension level sensors. Check the operation of the air suspension compressor. Carry out diagnostics of the electronic suspension control unit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1991?

Do not drive — repair immediately

How much does it cost to fix C1991?

The estimated repair cost for C1991 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat