Throttle Position Sensor Circuit Low Voltage
Throttle position sensor voltage is too low.
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What it means (plain English)
The throttle position sensor (TPS) tells the engine control module (ECM) how far the throttle is open. When the signal from this sensor is too low, the engine can't adjust the air-fuel mixture properly, leading to poor performance and potential stalling.
What the computer is actually seeing
The ECM expects a voltage from the throttle position sensor between 0.5V and 4.5V, indicating the position of the throttle plate. A reading below 0.5V indicates a fault in the sensor or circuit.
What a healthy reading looks like
TPS voltage should range from 0.5V (closed throttle) to 4.5V (wide-open throttle), with smooth increases in between.
Guided diagnostic — the DiagCoach way
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.
- 11. Check the wiring and connector at the throttle position sensor for damage or corrosion.
- 22. Measure the voltage at the throttle position sensor connector with the key on, engine off. Expected value is around 0.5 to 4.5V.
- 3 - If voltage is missing or below 0.5V, suspect a faulty sensor or wiring.
- 4 - If voltage is normal, check the signal wire to the ECM for continuity.
- 53. Perform a wiggle test on the wiring harness while monitoring the TPS voltage. Look for changes in voltage.
- 6 - If voltage fluctuates, repair or replace the wiring as needed.
- 74. If wiring is good, replace the throttle position sensor and clear the code. Re-test the system.
Common causes
- Faulty throttle position sensor
- Wiring issues or damaged connectors
- ECM problems
- Poor ground connections
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code on?
Yes, but expect reduced engine performance and responsiveness.
Will this code come back after clearing?
It may return if the underlying issue is not fixed.
Why does this code pair with SPN 2386?
Both codes relate to throttle position sensor faults, indicating varying degrees of sensor failure.
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