Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation
What does P2136 mean?
The P2136 code means the vehicle's onboard diagnostic system has detected: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation. This is a critical severity code.
Common Symptoms
- Reduced engine power
- Erratic throttle response
- Engine may hesitate or surge
- Limp mode warning
- Check engine light on
Probable Causes (Ranked by Likelihood)
- Worn throttle position sensor with mismatched A/B readings Very High
- Carbon buildup affecting TPS readings High
- Corroded throttle body connector Moderate
- Wiring issue causing one TPS track to read differently Moderate
- Electronic throttle body mechanical wear Low
Step-by-Step Diagnostic Procedure
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Compare TPS A and TPS B voltages on scan tool -- they should maintain a consistent ratio throughout throttle range
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Graph both TPS signals during a slow throttle sweep -- look for divergence at any point
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Clean electronic throttle body to eliminate carbon as a variable
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Inspect throttle body connector for corrosion affecting one circuit more than the other
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Replace throttle body if A/B correlation error persists after cleaning and connector inspection
Frequently Asked Questions
Can I drive with code P2136?
Only short distances. The PCM has detected that the two throttle position signals do not agree, which compromises its ability to accurately control the throttle. Reduced power mode is likely active.
What is A/B voltage correlation?
The electronic throttle body has two position sensor tracks (A and B) that should maintain a specific mathematical relationship. If sensor A reads a certain voltage, sensor B should read a predictable corresponding voltage. When this correlation breaks down, the PCM cannot trust the throttle position.
Is this the same as P2135?
They are closely related. P2135 specifically indicates the A/B correlation is out of range, while P2136 may indicate a broader correlation issue. Both point to the same general problem -- the two TPS tracks on the throttle body do not agree.