Power Steering Control Circuit High Voltage
The P0637 code indicates that the Power Steering Control Module (PSCM) has detected a voltage level in the control circuit that is higher than the manufacturer's specified range. This can be caused by a faulty PSCM, a short to voltage in the wiring, or a malfunctioning steering angle sensor. The system may reduce or disable power steering assist to prevent damage.
01. Most Common Causes
- Faulty Power Steering Control Module (PSCM)
- Short to voltage in the power steering control circuit wiring
- Malfunctioning steering angle sensor
- Corroded or damaged connectors in the power steering system
02. Symptoms You Will Notice
- Power steering warning light illuminated
- Increased steering effort, especially at low speeds
- Intermittent or complete loss of power steering assist
- Steering wheel vibration or unusual noises
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all stored codes and freeze frame data.
Step 2: Inspect the power steering control circuit wiring and connectors for damage, corrosion, or shorts.
Step 3: Test the voltage at the PSCM connector with the ignition on; compare to manufacturer specifications.
Step 4: Check the steering angle sensor for proper operation and signal voltage.
Step 5: If no wiring issues found, replace the Power Steering Control Module.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as power steering assist may fail, making steering difficult and increasing the risk of an accident.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor, depending on the cause and vehicle model.