The P0139 trouble code indicates a slow response in the oxygen (O2) sensor circuit of the bank 1 sensor 2. This code typically points to issues related to the oxygen sensor downstream of the catalytic converter, which monitors the oxygen content in the exhaust gas, affecting the emission control system.
O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)
Code symptoms P0139.
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 P0139.
1. Faulty oxygen (O2) sensor.
2. Wiring or connector issues within the sensor circuit.
3. Problems with the Engine Control Module (ECM).
Code Solutions P0139.
1. Replace the oxygen (O2) sensor if it is faulty.
2. Check and repair any wiring or connector issues in the sensor circuit.
3. If ECM issues are suspected, consult a qualified technician for diagnosis and potential reprogramming or replacement.