Minimum Throttle Position Not Learned (Toyota)
What does P1526 mean?
The P1526 code means the vehicle's onboard diagnostic system has detected: Minimum Throttle Position Not Learned (Toyota). This is a moderate severity code.
Common Symptoms
- High or fluctuating idle speed
- Check Engine Light illuminated
- Engine does not idle smoothly after battery disconnect
- Throttle response feels delayed
- Engine may stall at stops
Probable Causes (Ranked by Likelihood)
- Battery was recently disconnected or replaced Very High
- Throttle body was cleaned without performing relearn High
- ECU was reset or replaced Moderate
- Intermittent electrical connection to throttle body Moderate
- Faulty throttle body requiring replacement Low
Step-by-Step Diagnostic Procedure
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Perform a Toyota throttle body relearn procedure: key on engine off for 30 seconds, then start and idle for 10 minutes.
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If the relearn was already attempted, try clearing codes first then repeat the procedure.
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Check the throttle body connector for a secure connection.
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Monitor TPS voltage at idle on a scan tool. It should be stable and within specification.
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If the relearn repeatedly fails, the throttle body may need replacement.
Frequently Asked Questions
Why did this happen after replacing my battery?
When the battery is disconnected, the ECU loses its learned idle and throttle positions. The ECU must relearn these values through a specific procedure before it can properly control idle speed.
How do I perform the relearn procedure?
Turn the ignition to ON (do not start). Wait 30 seconds. Start the engine and let it idle for at least 10 minutes without touching the gas pedal. Turn off AC, headlights, and all accessories during the relearn.
Does this code clear on its own?
Sometimes, after enough drive cycles, the ECU will successfully relearn on its own. However, performing the proper relearn procedure will resolve it much faster and more reliably.