P2138 on SUBARU OUTBACK
Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to Subaru Outback context without treating complaints as confirmed diagnoses.
Sources: SAE/OBD-II definitions, manufacturer service information, and public reliability reports (including NHTSA where applicable).
- SAE J2012 Diagnostic Trouble Code Definitions — Generic diagnostic trouble code definition reference for P2138.
- NHTSA recalls, complaints, and manufacturer communications — Used to check public owner complaint context, recall status, and safety-related manufacturer communications by VIN or vehicle.
Limits: Guidance is informational and may not match every model-year or revision. Confirm with the official manual and diagnostics before replacing parts. For safety-critical or electrical work, use a qualified technician.
What P2138 Means on Your SUBARU OUTBACK
P2138 is a diagnostic trouble code indicating: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. This code relates to the fuel, air, emissions, or auxiliary powertrain control system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real SUBARU OUTBACK Owner Reports
Source: NHTSA Complaints Database
"Every once in a while the gas pedal stops functioning. it happens at highway speeds as well as local roads. when it does happen you have to find a safe spot to pull over and shut off the engine for at least a minute or more. restart the car and the pedal comes back. this is very hazardous."
"Please refer to code p2138 - throttle/pedal position sensor switch with "d"/"e" voltage correlation dtc severity 2 of 3 repair -- i believe elaine chao should be made aware of the safety issues affecting the general public regarding this dangerous issue -- my subaru outback accelerator will shut dow"
"As i was driving, i all of a sudden lost all power and control from the gas pedal. the car decelerated and i was only able to idle forward. the gas pedal became completely unresponsive. i turned the car off and restarted it."
"1) recurring phantom revving (in neutral and/or clutch depressed, both while completely stopped and while slowing down from any and all speeds) upwards of 4-5k rpm with difficulty getting the rpms back to normal."
"Error code p2138: some failure of pedal sensor assembly while in motion. exact issue unknown. acceleration goes limp and pedal becomes non-responsive. has happened in both city and highway driving situations."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on SUBARU OUTBACK
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
-
1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
-
2
Get a proper diagnosis
A code alone doesn't tell you the exact failed part. A diagnostic at a shop ($50–$150) pinpoints the root cause before you spend money on parts.
-
3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.