P0637
Power Steering Control Circuit High
Power steering control
Generic OBD-II
Medium
What it means
P0637 means the power-steering control circuit is reading a high voltage — usually an open or a short to power in the circuit the computer uses to command steering assist. Depending on the system, power-steering assist may be reduced or drop out. The engine still starts and runs normally.
Medium
Can I keep driving? Steering still works, but assist may be reduced or inconsistent so effort can increase — get it fixed soon, especially for low-speed maneuvering and parking.
Common symptoms
What you'll notice
- Reduced, heavy, or inconsistent power-steering assist
- Power-steering or check-engine warning light on
- Steering effort that changes or feels jerky
- Unusual noise from the power-steering system on some vehicles
Common causes
Most likely first
- Open circuit or short to power in the power-steering control wiringLikely
- Corroded or loose connector at the power-steering control module or actuatorCommon
- Faulty power-steering control moduleCommon
- Low system voltage (weak battery or alternator) on electric-assist systemsLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and scan for other power-steering codes.
- Inspect the control wiring and connector for opens and shorts to power.
- Verify system supply voltage and ground integrity.
- Test the control module's command signal to the steering actuator.
- Replace the module or actuator only if the wiring and supply check good.
FAQ
Quick answers
Is it safe to drive with P0637?+
It's driveable, but assist may drop out, making the wheel heavy — get it fixed soon, particularly if you rely on it for parking and slow turns.
Can I just clear P0637?+
It returns until the open or shorted control circuit is repaired.
Related codes
Often seen with P0637
Read & clear P0637 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX