Throttle/Pedal Position Sensor/Switch A Correlation

The computer compares signals from the throttle position sensor and accelerator pedal position sensor. If they don't match expected values, it sets this code. For example, if the throttle position is 70% open but the pedal shows only 30% pressed, the system triggers a fault.

The engine control module (ECM) sees a mismatch between the throttle position sensor (TPS) voltage and accelerator pedal position sensor (APPS) voltage. It expects a direct correlation, like 0.5V at idle and up to 4.5V at full throttle.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 1Check throttle body for binding or mechanical issues before testing sensors.
2. 2Inspect wiring and connectors for corrosion, damage, or loose connections.
3. 3Using a scan tool, monitor TPS and APPS voltage while moving the accelerator pedal. They should correlate closely.
4. 4If the TPS or APPS values are out of expected range, swap the faulty sensor with a known good one or replace as necessary.
5. 5If both sensors read correctly, consider ECM failure or further diagnosing the vehicle's wiring harness.

• Faulty throttle position sensor
• Faulty accelerator pedal position sensor
• Wiring issues or poor connections
• Mechanical binding in the throttle body
• Faulty engine control module (ECM)

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