Power Steering Control Circuit Malfunction
The P0635 code indicates a fault in the power steering control circuit, which can affect the electric power steering (EPS) system. This circuit includes the power steering control module, wiring, connectors, and related sensors. A malfunction may cause the power steering to become inoperative or behave erratically, leading to increased steering effort or loss of assist.
1. Most Common Causes
- Faulty power steering control module
- Damaged wiring or connectors in the control circuit
- Blown fuse or relay for the power steering system
- Low battery voltage or charging system issue
2. Symptoms You Will Notice
- Steering wheel feels heavy or difficult to turn
- Power steering warning light illuminated on dashboard
- Intermittent loss of power steering assist
- Steering wheel vibration or noise during turns
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional related codes.
Step 2: Inspect the power steering fuse and relay; replace if blown.
Step 3: Visually examine wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test battery voltage and charging system; ensure proper voltage (12.6V+ engine off, 13.5-14.5V running).
Step 5: If all else is okay, test the power steering control module per manufacturer procedure.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. The power steering may fail completely, making the vehicle difficult to control, especially at low speeds.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Repair costs vary: a new power steering control module can be $200-$800 plus labor, while wiring repairs are usually under $200.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.