Closed Throttle Position Not Learned (GM)
What does P1226 mean?
The P1226 code means the vehicle's onboard diagnostic system has detected: Closed Throttle Position Not Learned (GM). This is a low severity code.
Common Symptoms
- Check Engine Light on
- High idle speed
- Slightly erratic idle
- Minor throttle response delay
- No major drivability problems
Probable Causes (Ranked by Likelihood)
- Throttle body relearn not completed after replacement or cleaning Very High
- Battery disconnect that cleared throttle body learned values High
- Carbon buildup preventing throttle plate from closing fully Moderate
- Faulty throttle body motor Moderate
- PCM programming issue Low
Step-by-Step Diagnostic Procedure
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Perform a throttle body relearn procedure using a scan tool
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If relearn fails, clean the throttle body and retry
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Check that the throttle plate moves freely without sticking
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Verify the throttle body connector is secure
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If relearn still fails, the throttle body may need replacement
Frequently Asked Questions
How do I perform a throttle body relearn?
Most GM vehicles require a scan tool to command the relearn. The procedure typically involves turning the key on without starting, commanding the relearn, and waiting for confirmation. Some models can relearn by idling for 5-10 minutes.
Can P1226 set after disconnecting the battery?
Yes. When the battery is disconnected, the PCM loses its stored throttle body learned values. P1226 may set until a relearn procedure is performed or the vehicle has been driven enough for automatic relearning.
Is P1226 expensive to fix?
Often free or very inexpensive. A throttle body relearn can sometimes be done with a basic scan tool or key cycle procedure. If the throttle body is dirty, cleaning costs about $50-100. Replacement is only needed if the unit is faulty.