Throttle/Pedal Position Sensor/Switch B Circuit High Input
The PCM detected an abnormally high voltage signal from the Throttle Position Sensor/Switch B circuit, indicating the sensor is reading a position value that doesn't match actual throttle movement. This triggers limp mode, severely restricting engine acceleration to protect the engine from unintended wide-open throttle conditions.
What You Might Notice
- Severe limitation or complete loss of engine acceleration
- Stuck throttle position reading (at any RPM)
- Engine stalling during idle or low-speed operation
- Hesitation when attempting to accelerate
- Vehicle enters limp mode with reduced power output
Most Common Causes
- 1
Defective Throttle Position Sensor (TPS)
The TPS has failed internally and is sending an incorrect high voltage signal to the PCM regardless of actual throttle position.
- 2
Open or shorted wiring between TPS and PCM
A break in the circuit or short to power/ground in the sensor wiring harness prevents the PCM from receiving the correct throttle signal.
- 3
Corroded electrical connectors
Oxidation or corrosion on the TPS connector pins increases resistance, causing voltage readings to spike higher than normal.
- 4
Faulty drive-by-wire actuator or PCM
The electronic throttle control motor or PCM itself may be malfunctioning and misinterpreting sensor signals.
How to Diagnose It
- 1
Check Defective Throttle Position Sensor (TPS) — The TPS has failed internally and is sending an incorrect high voltage signal to the PCM regardless of actual throttle position.
- 2
Check Open or shorted wiring between TPS and PCM — A break in the circuit or short to power/ground in the sensor wiring harness prevents the PCM from receiving the correct throttle signal.
- 3
Check Corroded electrical connectors — Oxidation or corrosion on the TPS connector pins increases resistance, causing voltage readings to spike higher than normal.
- 4
Check Faulty drive-by-wire actuator or PCM — The electronic throttle control motor or PCM itself may be malfunctioning and misinterpreting sensor signals.
How to Fix It
- 1
Inspect and clean TPS connector
Locate the throttle position sensor connector, disconnect it, and clean all pins with electrical contact cleaner to remove corrosion. Reconnect firmly and retest for code clearance.
- 2
Replace Throttle Position Sensor
Remove the failed TPS from the throttle body assembly and install a new OEM or quality replacement sensor. Calibrate/relearn the sensor per manufacturer specifications.
- 3
Repair wiring harness and connectors
Inspect the wiring harness between the TPS and PCM for breaks, shorts, or damaged insulation. Repair or replace damaged sections and resolder any corroded connections.
- 4
Test and replace electronic throttle control motor if needed
Use a diagnostic scanner to verify the drive-by-wire actuator responds correctly to PCM commands. If unresponsive, the motor assembly may need replacement.
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