P0138 on Toyota
O2 Sensor Circuit High Voltage (Bank 1, Sensor 2)
P0138 on Toyota vehicles indicates o2 sensor circuit high voltage (bank 1, sensor 2). Au7o has documented this code across 1 Toyota model — most commonly on Camry. 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.
Common Causes of P0138
- •Faulty downstream O2 sensor
- •Short to voltage in signal wire
- •Coolant/contaminant on sensor
- •Rich exhaust condition
- •Wiring/connector fault
P0138 on Toyota by Model
Toyota Camry(1 issue)
- 2007-2010 2GR-FE P0138/P0158/P0606 Diagnostic Gates - T-SB-0001-102007-2010
Toyota T-SB-0001-10 Rev1 covers specified 2007-2009 Camry VDS BK46K and 2010 VDS BK3EK applications. P0138/P0158 may result from incorrect air-fuel-sensor response, and P0606 may also be present due to incorrect downstream O2-sensor operation. Toyota distinguishes these paths using the complete DTC set, freeze-frame air-fuel/O2 voltage and downstream O2 impedance, followed by circuit inspection. It does not describe every P0606 as a sensor fault or support the original 2AZ-FE, 2006-2012, VSC/TRAC or battery claims.
Looking for P0138 on a different make?
View P0138 across all makes →Frequently Asked Questions
What does P0138 mean on Toyota?▼
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. On Toyota specifically, this code is documented across 1 model.
What causes P0138 on Toyota vehicles?▼
Common causes on Toyota: Faulty downstream O2 sensor, Short to voltage in signal wire, Coolant/contaminant on sensor, Rich exhaust condition, Wiring/connector fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0138 on a Toyota?▼
Repair costs vary widely depending on the root cause and specific Toyota model.
Which Toyota models have P0138 documented?▼
Au7o has documented P0138 on 1 Toyota model: Camry.