Severity: Fix within days. Drive with caution and watch for new symptoms.
The catalytic converter on bank 1 is no longer cleaning the exhaust as well as it should. The computer knows this because the oxygen sensors before and after the converter are reading too similarly.
Rule out misfires, exhaust leaks, and the downstream oxygen sensor first. Replace the converter only after the real cause is found — a new converter will fail again if the cause is still there.
Usually safe to drive, but do not ignore it: a bad converter can be caused by a misfire, and a clogged one can choke the engine. Also, the car will fail an emissions test.
You can drive short distances carefully; watch for worsening symptoms. Usually safe to drive, but do not ignore it: a bad converter can be caused by a misfire, and a clogged one can choke the engine. Also, the car will fail an emissions test.
The most common causes are: Failing catalytic converter; Damaged or slow downstream oxygen sensor; Exhaust leak; Engine misfire that overheated the converter; Oil or coolant contamination. A scan tool and a visual check of the parts above is where a technician starts.
Rule out misfires, exhaust leaks, and the downstream oxygen sensor first. Replace the converter only after the real cause is found — a new converter will fail again if the cause is still there.
