The P0138 trouble code indicates that the oxygen (O2) sensor circuit of the bank 1 sensor 2 is experiencing high voltage. This code typically points to issues related to the oxygen sensor responsible for monitoring the oxygen content in the exhaust gas downstream of the catalytic converter, which affects the emission control system.
O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
Code symptoms P0138.
1. Poor fuel efficiency.
2. Engine performance issues.
3. Malfunction indicator light (MIL) illumination.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0138.
1. Faulty oxygen (O2) sensor.
2. High voltage or wiring issues within the sensor circuit.
3. Problems with the Engine Control Module (ECM).
Code Solutions P0138.
1. Replace the oxygen (O2) sensor if it is faulty.
2. Check and repair any high voltage or wiring issues in the sensor circuit.
3. If ECM issues are suspected, consult a qualified technician for diagnosis and potential reprogramming or replacement.