P2138 on SUBARU IMPREZA
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 Impreza 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 IMPREZA
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 IMPREZA Owner Reports
Source: NHTSA Complaints Database
"Driving about 30 - 35mph when all of a sudden the car lost power. the car did not stall, but engine went down to idle speed and my accelerator pedal had no throttle control. the "check engine " light came on as well as the "traction control" light."
"While driving in normal circumstances, engine power was lost, and complete loss of throttle control occurred. car would accelerate extremely slowly, and not past 20-25 mph (presumably 'engine fail-safe mode'?). thankfully not on a high-speed road."
"Car throws a p2138 code and car goes in limp mode with the accelerator pedal non-responsive. have to pull over and reset ecu to get back on road. have replaced accelerator pedal, throttle body, relay, and ecm at subaru dealership. happened dozens of times."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on SUBARU IMPREZA
Based on NHTSA complaint component analysis for this vehicle.
What To Do Next
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1
Check for recalls on YOUR VIN
Go to nhtsa.gov/recalls and enter your VIN. If your vehicle is covered, repairs are free.
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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.
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3
Compare repair quotes
Get 2–3 quotes. Dealer vs. independent shop prices often differ 30–50% for the same repair.