P0637Power Steering Control Circuit High
- Generic OBD-II code · Powertrain
- Can trigger limp mode
- How the car detects it
- P0635–P0637 concern the control or signal circuit between engine module and power steering – depending on the maker the drive of an electro-hydraulic pump or the steering load signal the engine module uses to raise idle. CARB requires power steering components to be monitored only if another diagnostic uses them, so these codes are rare and maker-specific. Mercedes-Benz stores P0635 in the electric steering module itself (no assist after start, software update); no engine module table available to us uses P0635–P0637. P0637 means the voltage in this circuit is too high – a short to battery voltage, or the driver or steering module reports a high state although 'off' was commanded; an electro-hydraulic pump may then keep running. No manufacturer threshold is published.
- What you may notice
- Power steering warning
- Heavy steering or pump running constantly
- Check engine light possible
- Likely causes
- LikelyControl or signal wire shorted to battery voltage
- PossibleSteering module or pump module faulty internally
- RareOvervoltage from the alternator regulator
- RareEngine module faulty
- Repair
- Medium · Usually a job for a workshop.Typical cost: €80 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.