P2136 critical

Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

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.

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Keep driving?: Short distances only
DIY difficulty: moderate
Estimated cost: $100 - $600 (parts and labor)

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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

Compare TPS A and TPS B voltages on scan tool -- they should maintain a consistent ratio throughout throttle range
Graph both TPS signals during a slow throttle sweep -- look for divergence at any point
Clean electronic throttle body to eliminate carbon as a variable
Inspect throttle body connector for corrosion affecting one circuit more than the other
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.