Variable Assist Solenoid Circuit Failure
The Power Steering Control Module (PSCM) or Powertrain Control Module (PCM) has detected an open, short to ground, or short to voltage in the variable assist power steering (VAPS) solenoid actuator circuit. This prevents the electronic modulation of hydraulic steering assist, typically resulting in a fixed or reduced power steering assist level.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty VAPS solenoid (internal open or short)
- Open, short to ground, or short to battery in the solenoid control circuit wiring
- Damaged, corroded, or loose connector terminals at the solenoid or control module
- Defective PSCM or PCM
3. Symptoms You Will Notice
- Steering feels heavy or inconsistent, especially at low speeds
- Power steering warning light illuminated on the dashboard
4. Step-by-Step Diagnosis
Scan for additional codes and verify C1921 is current
Visually inspect VAPS solenoid connector and wiring for damage, corrosion, or loose pins
Test solenoid resistance and check for shorts to ground or power using a multimeter
Check for battery voltage and ground at the solenoid connector with the ignition on
If wiring and solenoid test OK, suspect a faulty PSCM or PCM
5. Frequently Asked Questions
Is it safe to drive?▼
You can drive, but steering effort may be increased, especially at low speeds. Have it diagnosed soon to avoid further issues.
How much does it cost to fix?▼
Repair costs typically range from $150 to $600, depending on whether the solenoid, wiring, or control module needs replacement.