P0138 on Toyota Corolla
O2 Sensor Circuit High Voltage Bank 1 Sensor 2
Methodology: Reviewed against the SAE J2012 generic DTC definition and NHTSA owner-complaint patterns, then scoped to Toyota Corolla 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 P0138.
- 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 P0138 Means on Your Toyota Corolla
P0138 is a diagnostic trouble code indicating: O2 Sensor Circuit High Voltage Bank 1 Sensor 2. This code relates to the fuel and air metering system. The vehicle's computer detected a condition outside normal operating parameters and stored this code.
Real Toyota Corolla Owner Reports
Source: NHTSA Complaints Database
"My check engine light has come on and off sporadically, since the vehicle in question was bought of the showroom floor from sunny side toyota since march 2009 all the way up to the present."
"My ecm constantly have issues with stabilizing the vehicle on a daily occurrence. when it works as it should the car feels stable like it has added weight and the steering is responsive."
All reports filed by vehicle owners directly with the U.S. Department of Transportation.
📊 Complaint Trend by Model Year
Common Causes on Toyota Corolla
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.