What Does P0636 Mean?
The PCM has detected a low voltage condition in the power steering control circuit. The signal from the PCM to the power steering module is below the expected operating range, which may prevent proper speed-sensitive steering assist adjustment.
Common Causes
35%
Short to ground in the power steering control circuit wiring
30%
Faulty power steering control module with low output
20%
Corroded or damaged connector at the EPS module or PCM
15%
PCM internal power steering driver circuit failure
Diagnostic Steps
1
Step 1: Backprobe the power steering control signal wire at the PCM connector — measure voltage with key on, engine running. Compare to manufacturer specification.
2
Step 2: Disconnect the EPS module connector and measure the control signal wire to ground for short circuits — should read OL (infinite resistance).
3
Step 3: Inspect the wiring harness between the PCM and EPS module for damage, chafing against the steering column or body, and repair as needed.
4
Step 4: Check the EPS module power supply — a failed module can pull the control line low. Measure module power and ground independently.
5
Step 5: If wiring is intact and the module has proper power, test the PCM output with the EPS disconnected to determine if the PCM driver is at fault.
Estimated Repair Cost
$150 - $1,100
Parts + labor, varies by vehicle and location
The PCM has detected a low voltage condition in the power steering control circuit. The signal from the PCM to the power steering module is below the expected operating range, which may prevent proper speed-sensitive steering assist adjustment.
The most common cause of P0636 (Power Steering Control Circuit Low) is: Short to ground in the power steering control circuit wiring
Typical repair costs for P0636 range from $150 to $1,100, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Steering assist may be reduced or absent, particularly at low speeds. Vehicle is still controllable but requires significantly more effort. Repair promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0636 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
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