Throttle Position Sensor (TPS) Voltage Supply
Throttle position sensor voltage supply issue detected.
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What it means (plain English)
The computer is seeing a problem with the voltage supply to the throttle position sensor, which tells the engine how much gas to give.
What the computer is actually seeing
The power supply voltage to the throttle position sensor (TPS) is outside the expected range, usually under 0.5V or over 4.5V when it should be around 0.5V to 4.5V depending on throttle position.
What a healthy reading looks like
TPS power supply should read approximately 5V; a functional TPS signal should range from 0.5V (closed) to 4.5V (fully open).
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.
- 1Inspect the wiring and connectors for damage, corrosion or loose connections from the TPS to the ECU. Check for proper voltage supply; should be around 5V max.
- 2Check the throttle position sensor with a multimeter. At idle, it should be around 0.5V and increase smoothly to 4.5V as the throttle is opened. If outside this range, replace the sensor.
- 3Test for continuity in the circuit between the TPS and the computer. If there's an open circuit, repair as necessary.
- 4If repairs do not resolve the issue, consider scanning for other fault codes that may indicate ECU issues.
Common causes
- Damaged wiring or connectors to the TPS
- Faulty throttle position sensor
- ECU (Engine Control Unit) malfunction or programming issues
- Short in the electrical circuit supplying the TPS
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s not recommended to drive as this could impact engine performance and throttle response.
Will this code come back after I fix it?
If the underlying issue is truly resolved, the code should clear itself after a few drive cycles.
Why does this code pair with SPN 1385?
SPN 1385 indicates a throttle position sensor signal issue, which often coincides with voltage supply problems (SPN 1386), showing a broader problem with the TPS system.
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