Power Steering Control Circuit
P0635 indicates a malfunction in the power steering control circuit, meaning the PCM cannot properly communicate with or control the power steering system. This code sets when there's an electrical fault in the steering control circuit, such as a bad switch, wiring issue, or control module problem.
What You Might Notice
- Stiff or difficult steering response
- Erratic or unpredictable steering behavior
- Check engine light illuminated
- Reduced power steering assist
- Steering noise or grinding while turning
Most Common Causes
- 1
Defective power steering pressure switch
The pressure switch fails to send accurate signals to the PCM about steering system pressure, preventing proper power steering control and causing the code to set.
- 2
Faulty power steering position sensor
A defective steering position sensor cannot relay steering angle information to the control module, disrupting the power steering control loop.
- 3
Wiring faults or corroded connectors
Damaged wiring, loose connections, or corrosion in the power steering control circuit creates electrical resistance that prevents proper signal transmission to the PCM.
- 4
Low power steering fluid or internal leaks
Insufficient fluid level or pressure loss due to leaks causes the pressure switch to signal abnormal conditions, triggering the fault code.
How to Diagnose It
- 1
Check Defective power steering pressure switch — The pressure switch fails to send accurate signals to the PCM about steering system pressure, preventing proper power steering control and causing the code to set.
- 2
Check Faulty power steering position sensor — A defective steering position sensor cannot relay steering angle information to the control module, disrupting the power steering control loop.
- 3
Check Wiring faults or corroded connectors — Damaged wiring, loose connections, or corrosion in the power steering control circuit creates electrical resistance that prevents proper signal transmission to the PCM.
- 4
Check Low power steering fluid or internal leaks — Insufficient fluid level or pressure loss due to leaks causes the pressure switch to signal abnormal conditions, triggering the fault code.
How to Fix It
- 1
Test and replace power steering pressure switch
Use a multimeter to test the pressure switch resistance and continuity. If faulty, replace with a new pressure switch and verify the steering system responds normally.
- 2
Inspect and repair wiring and connectors
Check all power steering control circuit wiring for damage, corrosion, or loose connections. Clean corroded connectors and repair or replace damaged wiring as needed.
- 3
Check and top off power steering fluid
Inspect the power steering fluid level and condition. Top off if low and check for leaks in hoses and the pump. Address any leaks found before proceeding.
- 4
Replace power steering position sensor
If the steering position sensor is faulty, remove the old sensor and install a new one, then clear the code and test steering response.
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