P0138 on 2007-2010 Toyota Camry — O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
1 vehicles · 1 makes
Most Reported On
P0138 is an OBD-II diagnostic trouble code meaning “O2 Sensor Circuit High Voltage (Bank 1, Sensor 2).” The PCM detects a persistently high voltage from the Bank 1, Sensor 2 downstream O2 sensor, indicating a short to voltage, contamination, or a rich condition at the post-catalyst sensor. This code is most commonly reported on 2007-2010 Toyota Camry.
Common Causes
Diagnostic Tools
To diagnose P0138, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
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Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
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Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
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FAQ
What does P0138 mean?
P0138 stands for "O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)." The PCM detects a persistently high voltage from the Bank 1, Sensor 2 downstream O2 sensor, indicating a short to voltage, contamination, or a rich condition at the post-catalyst sensor.
What are the most common causes of P0138?
The most common causes of P0138 are: Faulty downstream O2 sensor, Short to voltage in signal wire, Coolant/contaminant on sensor, Rich exhaust condition, Wiring/connector fault. The specific cause varies by vehicle.
How much does it cost to fix P0138?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P0138?
Au7o has documented P0138 across 1 vehicle models from 1 manufacturers: Toyota.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.