Throttle Position Sensor 1 Voltage Below Normal
The throttle position sensor is sending a low voltage signal to the engine control module.
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What it means (plain English)
Inside the throttle body, there's a sensor that tells the engine how open the throttle is. It should send a voltage between 0.5V to 4.5V depending on how much you're pressing the accelerator. If it drops below this range, the computer thinks the throttle is nearly closed, affecting performance.
What the computer is actually seeing
The engine control module expects a throttle position sensor voltage between 0.5V and 4.5V at idle and full throttle. If the voltage goes below 0.5V, it triggers this fault code.
What a healthy reading looks like
0.5V (closed throttle) to 4.5V (wide open throttle) based on pedal position.
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 throttle position sensor wiring and connectors for any visible damage or corrosion. Decision: If damaged, repair or replace the wiring/connectors before testing further.
- 22. Measure the voltage at the throttle position sensor connector while the engine is running. Expect 0.5V to 4.5V. Decision: If the voltage is below 0.5V, proceed to step 3; if within range, consider checking the engine control module.
- 33. Disconnect the throttle position sensor and inspect for internal damage or corrosion. Test the sensor for proper resistance according to manufacturer specifications. Decision: If it fails, replace the throttle position sensor; if it passes, check the engine control module.
- 44. If the sensor and wiring are good, check the battery voltage. Should be above 12.5V with the engine off. Decision: If voltage is low, charge the battery before retesting.
Common causes
- Faulty throttle position sensor
- Wiring issues or broken connectors
- Throttle body issues such as carbon buildup or mechanical faults
- Low battery voltage affecting sensor output
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive as throttle response may be poor, affecting drivability.
Will this code come back after clearing it?
If the underlying issue isn’t fixed, the code will likely return after clearing.
Why does this code pair with SPN 1519?
Both relate to the throttle position sensor; one indicates a voltage issue, while the other indicates performance or range issues.
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