Throttle/Pedal Position Sensor/Switch "D" Circuit
The throttle position sensor (TPS) or its circuit is malfunctioning, preventing the engine control module from accurately reading throttle position. This causes improper fuel and ignition timing, leading to rough idle, stalling, or misfiring.
What You Might Notice
- Check engine light illumination
- Rough or unstable idle
- Misfiring at idle or highway speeds
- Engine stalls or won't idle smoothly
- Difficulty starting or starts then stalls immediately
Most Common Causes
- 1
Bad throttle position sensor (TPS)
The TPS potentiometer has failed or developed an internal electrical fault, sending incorrect voltage signals to the PCM about throttle position.
- 2
Sticking throttle return spring
The throttle body return spring is stuck or binding, preventing smooth throttle operation and causing sensor signal errors.
- 3
Corroded or damaged connector
The TPS or MAP sensor connector has corrosion, poor contact, or broken pins that disrupt the electrical signal to the PCM.
- 4
Misrouted or chafed wiring harness
The TPS circuit wiring is pinched, chafed, or routed incorrectly, causing intermittent electrical faults or short circuits.
How to Diagnose It
- 1
Check Bad throttle position sensor (TPS) — The TPS potentiometer has failed or developed an internal electrical fault, sending incorrect voltage signals to the PCM about throttle position.
- 2
Check Sticking throttle return spring — The throttle body return spring is stuck or binding, preventing smooth throttle operation and causing sensor signal errors.
- 3
Check Corroded or damaged connector — The TPS or MAP sensor connector has corrosion, poor contact, or broken pins that disrupt the electrical signal to the PCM.
- 4
Check Misrouted or chafed wiring harness — The TPS circuit wiring is pinched, chafed, or routed incorrectly, causing intermittent electrical faults or short circuits.
How to Fix It
- 1
Replace throttle position sensor
Remove the old TPS from the throttle body and install a new sensor, then clear the code and test idle quality.
- 2
Inspect and repair TPS connector
Check the TPS connector for corrosion, loose pins, or damage; clean contacts or replace connector as needed.
- 3
Service throttle return spring
Clean the throttle body and apply throttle cleaner; lubricate or replace the return spring if sticking or damaged.
- 4
Check and reroute wiring harness
Inspect the TPS circuit harness for cuts, abrasions, or improper routing; repair or replace damaged sections and secure away from heat sources.
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