What Does P1651 Mean?
The Engine Control Module has detected an implausible signal or circuit fault from the power steering pressure switch. This switch signals the ECM when steering effort is high so idle speed can be increased to prevent stalling.
Common Causes
40%
Failed power steering pressure switch
25%
Open or shorted wiring to power steering pressure switch
20%
Corroded or loose connector at pressure switch
10%
Low power steering fluid causing erratic pressure readings
5%
ECM internal fault in switch input circuit
Diagnostic Steps
1
Step 1: Locate power steering pressure switch (typically on power steering pump or high-pressure line)
2
Step 2: Check power steering fluid level and condition; top off if low
3
Step 3: Monitor switch signal voltage with key on and engine off (should read battery voltage or 0V depending on design)
4
Step 4: Start engine and turn steering wheel lock-to-lock while monitoring switch signal (should toggle between high and low)
5
Step 5: Check switch connector for corrosion and test wiring for continuity and shorts to ground/power
Estimated Repair Cost
$100 - $350
Parts + labor, varies by vehicle and location
The Engine Control Module has detected an implausible signal or circuit fault from the power steering pressure switch. This switch signals the ECM when steering effort is high so idle speed can be increased to prevent stalling.
The most common cause of P1651 (Power Steering Pressure Switch Input fault) is: Failed power steering pressure switch
Typical repair costs for P1651 range from $100 to $350, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Engine may idle rough or stall when steering at low speeds or when stationary. Power steering function itself is not affected.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1651 to identify the root cause.
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Quick Info
Category
Powertrain
System
Power Steering / Idle Control
Difficulty
Type
Manufacturer
Recommended Tools
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