P2151 low

Throttle/Pedal Position Sensor/Switch B Circuit Low

The P2151 code means the vehicle's onboard diagnostic system has detected: Throttle/Pedal Position Sensor/Switch B Circuit Low. This is a low severity code.

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Keep driving?: Yes, but fix soon
DIY difficulty: moderate
Estimated cost: $80 - $400 (parts and labor)

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Common Symptoms

Check Engine Light on
Reduced engine power warning
Erratic throttle response
Engine may enter limp mode
Poor acceleration

Probable Causes (Ranked by Likelihood)

Short to ground in TPS B circuit Very High
Failed TPS B with low output High
Wiring shorted to engine ground Moderate
ECM input shorted Low

Step-by-Step Diagnostic Procedure

Read TPS B voltage on scan tool at closed and wide open throttle
Inspect TPS B wiring and connector
Measure TPS B reference voltage (should be approximately 5V)
Compare TPS B to TPS A readings for correlation

Frequently Asked Questions

What does P2151 mean?

P2151 indicates: Throttle/Pedal Position Sensor/Switch B Circuit Low. The ECM detected an abnormal condition in this sensor circuit.

Is P2151 serious?

Low severity, but should be repaired to maintain proper engine management.

What should I check first?

Start with a visual inspection of the sensor wiring and connector. Use a scan tool to read sensor data and compare to expected values. Check reference voltage (typically 5V) at the sensor connector.