P2138 Throttle/Pedal Position Sensor/Switch 'D'/'E' Voltage Correlation
The accelerator pedal has two sensors that should agree, and they don't. Because this is a safety system, the car will usually limit power.
Common causes
- Faulty accelerator pedal sensor assembly
- Damaged wiring or connector
- Throttle body problem
Symptoms
- Reduced power or 'limp mode', poor or no acceleration, warning lights
Can I drive with it?
Drive carefully and get it fixed soon: the car can suddenly cut power, which is risky in traffic or when merging.
Tip: In the NHTSA data this code comes mostly from Chevrolet, Subaru and Buick owners.
Which scanner reads it?
Any OBD2 scanner reads it. Live pedal-position data shows whether both sensors agree.
Budget tools like the ANCEL AD310 read it; tools with live data and graphing – like the BlueDriver or OBDLink MX+ – help you find the cause. Not sure which fits you? Try the Find My Scanner quiz.
In the data
Of the vehicle complaints owners filed with NHTSA from 2015 to 2025, 208 quote P2138 – most often from Chevrolet, Subaru, Buick owners. Complaints lean toward serious problems, so treat this as a sign of how often the code turns up in real reports, not how often cars get it.
Both sources are compared on the Trends page.
Related codes
General information to help you understand a code – not a diagnosis. Your car’s service information or a qualified mechanic has the final word. See how we research.