Emissions codes
Catalytic converter, oxygen sensor, EVAP and EGR codes. Pick your code for what it means, whether you can drive, common causes and what the repair usually costs.
| Code | What it means | Drive? | Typical, Boston |
|---|---|---|---|
| P0030 | Oxygen sensor heater circuit fault (bank 1, before converter) | Usually | $110 to $370 |
| P0031 | Oxygen sensor heater circuit low (bank 1, before converter) | Usually | $110 to $370 |
| P0032 | Upstream oxygen sensor heater control high (bank 1) | Usually | $110 to $370 |
| P0036 | Oxygen sensor heater circuit fault (bank 1, after converter) | Usually | $110 to $370 |
| P0037 | Oxygen sensor heater circuit low (bank 1, after converter) | Usually | $110 to $370 |
| P0038 | Downstream oxygen sensor heater control circuit high (bank 1) | Usually | $110 to $370 |
| P0050 | Upstream oxygen sensor heater control problem (bank 2) | Usually | $110 to $370 |
| P0051 | Upstream oxygen sensor heater control low (bank 2) | Usually | $110 to $370 |
| P0053 | Upstream oxygen sensor heater resistance wrong (bank 1) | Usually | $110 to $370 |
| P0130 | Upstream oxygen sensor circuit problem (bank 1) | Short trips | $110 to $370 |
| P0131 | Oxygen sensor reads low voltage (bank 1, before converter) | Usually | $110 to $370 |
| P0132 | Oxygen sensor reads high voltage (bank 1, sensor 1) | Short trips | $110 to $370 |
| P0133 | Oxygen sensor responding slowly (bank 1, before converter) | Usually | $110 to $370 |
| P0134 | Oxygen sensor not responding (bank 1, before converter) | Usually | $110 to $370 |
| P0135 | Oxygen sensor heater fault (bank 1, before converter) | Usually | $110 to $370 |
| P0136 | Downstream oxygen sensor circuit problem (bank 1) | Usually | $110 to $370 |
| P0137 | Rear oxygen sensor reads low (bank 1, after converter) | Usually | $110 to $370 |
| P0138 | Rear oxygen sensor reads high (bank 1, after converter) | Usually | $110 to $370 |
| P0139 | Downstream oxygen sensor slow to respond (bank 1) | Usually | $110 to $370 |
| P0140 | Downstream oxygen sensor shows no activity (bank 1) | Usually | $110 to $370 |
| P0141 | Oxygen sensor heater fault (bank 1, after converter) | Usually | $110 to $370 |
| P0151 | Upstream oxygen sensor voltage too low (bank 2) | Short trips | $110 to $370 |
| P0153 | Upstream oxygen sensor slow to respond (bank 2) | Short trips | $110 to $370 |
| P0155 | Upstream oxygen sensor heater circuit problem (bank 2) | Usually | $110 to $370 |
| P0157 | Rear oxygen sensor reads low (bank 2, after converter) | Usually | $110 to $370 |
| P0158 | Downstream oxygen sensor reads high voltage (bank 2) | Usually | $110 to $370 |
| P0161 | Oxygen sensor heater fault (bank 2, after converter) | Usually | $110 to $370 |
| P0401 | Exhaust gas recirculation flow too low | Usually | $160 to $760 |
| P0402 | Exhaust recirculation flow too high | Short trips | $160 to $760 |
| P0403 | Exhaust recirculation valve control circuit problem | Short trips | $160 to $760 |
| P0404 | Exhaust recirculation system not working as commanded | Short trips | $160 to $760 |
| P0410 | Secondary air system fault | Usually | $270 to $1,175 |
| P0411 | Secondary air system flow not right | Usually | $270 to $1,175 |
| P0420 | Catalytic converter not working well (bank 1) | Usually | $400 to $1,900 |
| P0421 | Catalytic converter slow to clean up after warm-up (bank 1) | Usually | $400 to $1,900 |
| P0430 | Catalytic converter not working well (bank 2) | Usually | $400 to $1,900 |
| P0440 | Fuel vapor system problem | Usually | $5 to $110 |
| P0441 | Fuel vapor purge flow wrong | Usually | $85 to $260 |
| P0442 | Small fuel vapor leak | Usually | $5 to $110 |
| P0443 | Purge valve circuit problem | Usually | $85 to $260 |
| P0446 | Fuel vapor vent circuit problem | Usually | $120 to $360 |
| P0449 | Fuel vapor vent valve circuit problem | Usually | $120 to $360 |
| P0452 | Fuel vapor system pressure sensor reads low | Usually | $120 to $360 |
| P0453 | Fuel vapor pressure sensor signal too high | Usually | $120 to $360 |
| P0455 | Large fuel vapor leak | Usually | $5 to $110 |
| P0456 | Very small fuel vapor leak | Usually | $5 to $110 |
| P0457 | Fuel vapor leak, gas cap may be loose | Usually | $5 to $110 |
| P0491 | Secondary air system flow too low (bank 1) | Usually | $270 to $1,175 |
| P0496 | Fuel vapor purge flow while engine off | Usually | $85 to $260 |
| P1000 | Emissions self-tests not finished yet | Usually | $60 to $290 |
| P1450 | Fuel tank vacuum problem | Usually | $120 to $360 |
| P2195 | Upstream oxygen sensor stuck lean (bank 1) | Short trips | $110 to $370 |
| P2198 | Upstream oxygen sensor stuck rich (bank 2) | Short trips | $110 to $370 |
| P2270 | Downstream oxygen sensor stuck lean (bank 1) | Usually | $110 to $370 |
Typical range, estimate, for the most common repair for each code. Prices updated October 2026. Not a repair shop, estimates only.