P2135: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation

What does P2135 mean?

The A and B position inputs do not agree in the relationship expected by the computer. Redundant throttle/pedal signals are a safety check, so the controller may restrict power even when one channel appears normal.

Generic OBD-II definition: Throttle/Pedal Position Sensor/Switch A/B Voltage Correlation. Confirm applicability in your vehicle service information.

Common causes

• Poor throttle or pedal connector contact
• Worn position-sensor track
• Shorted or open signal wiring
• Throttle assembly or calibration problem

Symptoms

• Sudden reduced power
• Erratic acceleration
• Stalling or unreliable throttle response

Diagnostic focus

A and B are not necessarily equal voltages. Some designs use opposite slopes or a fixed ratio; compare with the factory relationship rather than trying to make the readings match.

Can I keep driving with P2135?

Severity: High Unreliable throttle response can be dangerous. Do not continue driving with surging, stalling, or reduced acceleration that makes traffic unsafe; arrange recovery instead. Do not force an electronic throttle plate.

If the check engine light is flashing or the car runs badly, stop driving and have it checked.

Typical fixes

• Identify which paired sensors the engine monitors
• Graph both channels and check shared supply/ground
• Inspect the connector and check applicable service bulletins

Sources & review

• OBD-Codes.com: P2135
• TroubleCodes.net: P2 code definitions

Definitions and diagnostic background checked 2026-11-06. Generic guidance, not a substitute for the service procedure for your exact year, engine, and transmission.