Throttle/Pedal Pos Sensor/Switch A / B Voltage Correlation
P2135 indicates a voltage correlation mismatch between the throttle position sensor (TPS) or accelerator pedal position sensor inputs. The engine control module detects that the signals from these sensors are not correlating properly with each other, which compromises throttle control and engine response.
What You Might Notice
- Check engine light illuminated
- Engine stalling at stops or idle
- Lack of power or acceleration
- Sudden loss of power during cruise
- Throttle stuck at current RPM
Most Common Causes
- 1
Faulty Throttle Position Sensor (TPS)
A defective or out-of-calibration TPS produces inconsistent voltage signals that don't match expected values, causing the correlation fault to set.
- 2
Defective Accelerator Pedal Position Sensor
A failing pedal position sensor sends erratic signals that fail to correlate with the throttle position, triggering the diagnostic code.
- 3
Wiring or Connector Issues
Corroded connectors, broken wires, or loose connections in the TPS or pedal sensor circuits prevent proper signal transmission and correlation.
- 4
Engine Control Module (ECM) Malfunction
A faulty ECM may fail to properly read or process sensor signals, generating a false correlation fault even when sensors are functioning correctly.
How to Diagnose It
- 1
Check Faulty Throttle Position Sensor (TPS) — A defective or out-of-calibration TPS produces inconsistent voltage signals that don't match expected values, causing the correlation fault to set.
- 2
Check Defective Accelerator Pedal Position Sensor — A failing pedal position sensor sends erratic signals that fail to correlate with the throttle position, triggering the diagnostic code.
- 3
Check Wiring or Connector Issues — Corroded connectors, broken wires, or loose connections in the TPS or pedal sensor circuits prevent proper signal transmission and correlation.
- 4
Check Engine Control Module (ECM) Malfunction — A faulty ECM may fail to properly read or process sensor signals, generating a false correlation fault even when sensors are functioning correctly.
How to Fix It
- 1
Inspect and Clean Sensor Connectors
Remove corrosion from throttle position and accelerator pedal sensor connectors using contact cleaner and a soft brush. Ensure connections are tight and free of debris.
- 2
Replace Throttle Position Sensor
Remove and replace the TPS with a new OEM or quality aftermarket sensor, then clear the code and perform a test drive to verify resolution.
- 3
Replace Accelerator Pedal Position Sensor
Disconnect and remove the pedal position sensor assembly, install a new unit, then reprogram if necessary and clear diagnostic codes.
- 4
Repair Wiring and Harnesses
Inspect wiring harnesses between the sensors and ECM for damage, burns, or pinched areas. Repair or replace compromised wiring sections.
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