Throttle Position Sensor Learned Closed Throttle Position Out of Range (Toyota)
What does P1525 mean?
The P1525 code means the vehicle's onboard diagnostic system has detected: Throttle Position Sensor Learned Closed Throttle Position Out of Range (Toyota). This is a moderate severity code.
Common Symptoms
- Rough or unstable idle
- Check Engine Light illuminated
- Idle speed too high or too low
- Engine may stall after starting
- Throttle response may feel abnormal
Probable Causes (Ranked by Likelihood)
- Dirty throttle body Very High
- Faulty throttle position sensor High
- Throttle body not returned to factory calibration after cleaning High
- Damaged throttle body motor Moderate
- ECU needs idle relearn procedure Low
Step-by-Step Diagnostic Procedure
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Clean the throttle body and perform an idle relearn procedure.
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Monitor TPS voltage at closed throttle. It should be approximately 0.3 to 0.7V depending on the model.
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Check the throttle body connector for corrosion or damage.
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Verify the throttle plate moves freely without binding.
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Perform the Toyota idle relearn: warm up the engine, turn off all accessories, and let it idle for 10 minutes.
Frequently Asked Questions
What does 'learned closed throttle position' mean?
The ECU learns and stores the TPS voltage when the throttle plate is fully closed. If this learned value drifts out of the acceptable range due to carbon or sensor drift, P1525 is set.
Is an idle relearn necessary on Toyota?
Yes. After cleaning the throttle body or disconnecting the battery, Toyota vehicles need an idle relearn. Warm the engine, turn off all accessories, and let it idle undisturbed for 5 to 10 minutes.
Can I do the relearn without a scan tool?
On most Toyota vehicles, yes. The basic idle relearn involves warming the engine and letting it idle. However, a scan tool can speed up the process and confirm the new learned values.