This code indicates the catalytic converter on engine Bank 2 is not reducing exhaust emissions as efficiently as designed. The vehicle's computer compares signals from the upstream and downstream oxygen sensors to determine converter health. If the downstream sensor activity mimics the upstream sensor too closely, the system logs this fault.
Internal substrate damage or contamination reduces oxygen storage capacity.
Leaks before the downstream sensor introduce false oxygen readings.
Sensor response time is too slow or signal is stuck.
Unburned fuel overheats and damages the converter over time.
Incorrect air/fuel ratio data skews efficiency calculations.
Control module fails to process sensor data correctly (rare).
Yes, the vehicle is usually safe to drive, but prolonged driving may damage other components and the vehicle will fail emissions tests.
No, exhaust leaks or faulty oxygen sensors can trigger this code without converter failure.
No, replacing the PCM is rarely the solution for efficiency codes and should only be considered after all other components are ruled out.
No, resetting clears the light temporarily, but the code will return once the monitor runs if the underlying issue persists.