P0637 Power steering control circuit: signal or voltage too high

By: Diagno editorial team · Updated: 2026-10-15

P0637 means: Power steering control circuit: signal or voltage too high. The steering or chassis system (steering angle sensor, electric power steering, suspension, brakes) found a fault. Drive gently and have the car checked soon. The repair usually costs about €60–400 in Estonia. The most common cause: connector loose, damp or corroded.

What it means

The steering or chassis system (steering angle sensor, electric power steering, suspension, brakes) found a fault. The signal voltage is too high. Usually a wire is shorted to power, the ground is broken or the part itself has failed.

What you may notice

• Warning light on
• Steering may be heavy
• ESP may be switched off

What could be wrong

1. 1Connector loose, damp or corroded
2. 2Wire shorted to power or ground broken
3. 3Faulty sensor or steering unit
4. 4Engine computer fault (rare)

Repair difficulty: Moderate

What you can check yourself

First look at the connector and wiring: anything loose, melted or green with corrosion? If the steering is heavy, drive carefully. After tyre or alignment work the steering angle sensor often needs recalibrating. Best left to a workshop. It needs a diagnostic tool and experience.

How we fix it

1. We read the fault data on the diagnostic tool and check whether the fault is constant
2. We measure the circuit's supply, ground and signal
3. We repair the wire or replace the connector
4. If the wiring is fine, we replace the sensor or steering unit

Standard SAE description: Power Steering Control Circuit High