P2138 on Gmc Acadia
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 Gmc Acadia 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 Gmc Acadia
P2138 is a diagnostic trouble code indicating: Throttle/Pedal Position Sensor/Switch D/E Voltage Correlation. This code relates to the powertrain system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real Gmc Acadia Owner Reports
Source: NHTSA Complaints Database
"Vehicle producing code P2138 then goes into limp mode stating to service stability, traction control off and engine reduced power. Replaced Throttle Body and Acceleration Pedal Position Sensor and error was still present."
"I’m just reporting several known issues. First, with code P2138, which I got today at Oreilly after my car started throwing warnings."
"The ACADIA 2020 while in slow motion approaching my private condominium parking spot, accelerated autonomously and then slammed into the cement wall. Airbags deployed, no warning of collision, seriously damaged both car and cement wall. No bodily injuries."
"The contact owns a 2021 GMC Acadia. The contact stated while driving 50 MPH, the vehicle suddenly decelerated to 35 MPH. The vehicle stalled, and the "Steering Assistance Reduced" message was displayed. The vehicle was restarted."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on Gmc Acadia
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.