Rear Height Sensor Circuit Low Voltage
The Air Suspension Control Module (ASCM) has detected an abnormally low signal voltage on the rear height sensor circuit, below the calibrated threshold (typically less than 0.5V). This indicates a short-to-ground in the signal wire, a faulty sensor (Hall effect or potentiometer), or an internal ASCM failure, preventing accurate vehicle height measurement.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty rear height sensor (internal short)
- Signal wire shorted to ground (chafed or pinched insulation)
- Corroded, wet, or bent pins in sensor or module connector contacting the housing
- Internal failure of the ASCM on the signal input pin
3. Symptoms You Will Notice
- Suspension warning light illuminated
- Vehicle sitting unevenly or at incorrect ride height
- Air suspension inoperative or stuck in one position
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to the code.
Visually inspect the rear height sensor wiring and connector for damage, corrosion, or bent pins.
Measure voltage at the sensor signal wire with key on; if below 0.5V, suspect a short-to-ground.
Disconnect the sensor and check if voltage rises; if so, replace the sensor.
If voltage remains low, isolate the signal wire and check for continuity to ground; repair as needed.
If wiring and sensor are good, test the ASCM by backprobing the signal pin; replace module if faulty.
5. Frequently Asked Questions
Is it safe to drive?▼
No, driving with this fault can cause unstable ride height and handling, potentially leading to loss of control. Have the vehicle towed to a repair shop.
How much does it cost to fix?▼
Repair costs typically range from $200 to $800, depending on whether the sensor ($100-$300), wiring repair ($100-$200), or ASCM ($400-$800) needs replacement.