Catalytic Converter / Emissions System
Caution — Service soon
What It Means
The catalytic converter or downstream emissions system has a fault. This may indicate a failing catalytic converter, which is one of the most expensive emissions repairs and often a symptom of an underlying engine issue (misfire, oil burning, rich fuel mixture) that damaged the converter.
Common Causes
- Engine misfire dumping unburned fuel into the exhaust (most common cause of cat failure)
- Burning oil (worn piston rings, valve seals) contaminating the converter
- Rich fuel mixture (faulty O2 sensor, MAF, or fuel injector)
- Physical damage to converter (impact with road debris)
- Normal aging (converters last 100K-150K miles under normal conditions)
Can I Still Drive?
Yes short-term — but address promptly. A failing catalytic converter will eventually clog, causing loss of power, stalling, and potentially engine damage from excessive backpressure. Also: fix the ROOT CAUSE (misfire, oil burning) before replacing the converter, or the new one will fail too.
Estimated Repair Cost
$500 – $3,000
This is an estimate only. Actual costs vary by vehicle make, model, year, location, and shop labor rates. Always get multiple quotes for major repairs.
Related OBD-II Trouble Codes
These OBD codes are commonly associated with this warning light. Scan your vehicle with an OBD-II scanner to get the exact code before diagnosing.