Throttle/Pedal Pos Sensor/Switch A / C Voltage Correlation
P2136 indicates the throttle pedal position sensor voltage signals are not correlating properly between sensor inputs A and C. The engine control module detects a mismatch between multiple pedal position sensors, which can cause erratic throttle response and drivability issues.
What You Might Notice
- Engine stalling at stops or low speeds
- Total loss of engine power or severe lack of acceleration
- Sudden power loss during cruise
- Throttle stuck at current RPM without responding to pedal input
- Check engine light illuminated
Most Common Causes
- 1
Throttle pedal sensor failure
One or both pedal position sensors (A or C) have failed or are sending incorrect voltage signals. This is the most common cause of correlation faults.
- 2
Wiring issues or poor connections
Corroded, loose, or damaged wiring between the pedal sensors and engine control module prevents accurate signal transmission.
- 3
Engine control module malfunction
The ECM may have internal circuit failure preventing proper sensor signal processing and comparison.
- 4
Pedal mechanical binding or wear
Physical damage to the pedal assembly or sensor mounting can cause sensors to output inconsistent voltage signals.
How to Diagnose It
- 1
Check Throttle pedal sensor failure — One or both pedal position sensors (A or C) have failed or are sending incorrect voltage signals. This is the most common cause of correlation faults.
- 2
Check Wiring issues or poor connections — Corroded, loose, or damaged wiring between the pedal sensors and engine control module prevents accurate signal transmission.
- 3
Check Engine control module malfunction — The ECM may have internal circuit failure preventing proper sensor signal processing and comparison.
- 4
Check Pedal mechanical binding or wear — Physical damage to the pedal assembly or sensor mounting can cause sensors to output inconsistent voltage signals.
How to Fix It
- 1
Inspect and test throttle pedal sensors
Use a multimeter to test voltage output of both sensor A and C at various pedal positions. Replace any sensor that fails voltage specifications or shows inconsistent readings.
- 2
Check pedal sensor wiring and connectors
Inspect all wiring harnesses and connectors between the pedal assembly and ECM for corrosion, damage, or loose connections. Clean connectors with electrical contact cleaner and reseat firmly.
- 3
Clear code and retest
After repairs, clear the trouble code using a diagnostic scanner and test drive the vehicle to verify the correlation fault does not return.
- 4
Replace engine control module if necessary
If sensors and wiring are confirmed good but code persists, the ECM may require replacement. This is typically a last resort after all other components are verified.
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