What Does P0635 Mean?
The PCM has detected a malfunction in the power steering control circuit. In vehicles with electronically controlled power steering (EPS/EHPS), the PCM communicates with the power steering module to adjust assist levels based on vehicle speed. This code indicates a general fault in that communication or control circuit.
Common Causes
35%
Faulty power steering control module or EPS motor
30%
Damaged wiring or connectors in the power steering control circuit
20%
CAN bus communication fault between PCM and EPS module
15%
PCM internal driver circuit failure for PS control
Diagnostic Steps
1
Step 1: Check for additional codes in the EPS/power steering module using a scan tool — these codes will provide more specific fault information.
2
Step 2: Inspect the EPS motor and module connectors for corrosion, water intrusion, or damaged pins — clean and repair as needed.
3
Step 3: Verify CAN bus communication between the PCM and EPS module — check for proper termination resistance (approximately 60 ohms between CAN-H and CAN-L at the diagnostic port).
4
Step 4: Measure the power and ground supply to the EPS module — typical systems require a dedicated high-current fuse (40-80A) and a clean ground.
5
Step 5: If communication and power are good, the EPS module or motor assembly may need replacement.
Estimated Repair Cost
$150 - $1,200
Parts + labor, varies by vehicle and location
The PCM has detected a malfunction in the power steering control circuit. In vehicles with electronically controlled power steering (EPS/EHPS), the PCM communicates with the power steering module to adjust assist levels based on vehicle speed. This code indicates a general fault in that communicatio...
The most common cause of P0635 (Power Steering Control Circuit) is: Faulty power steering control module or EPS motor
Typical repair costs for P0635 range from $150 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Power steering assist may be reduced or lost entirely, making the vehicle very difficult to steer at low speeds. Drive with extreme caution and avoid parking lot maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0635 to identify the root cause.
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Quick Info
Category
Powertrain
System
Power Steering System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
