P04XX Codes – Auxiliary Emission Controls
Discover all emission-related OBD-II codes in the P04XX range. These codes target components like the EGR valve, EVAP system, and purge solenoids responsible for reducing harmful emissions.
| DTC Number | DTC Naming | Location |
| P0400 | Exhaust Gas Recirculation "A" Flow | |
| P0401 | Exhaust Gas Recirculation "A" Flow Insufficient Detected | |
| P0402 | Exhaust Gas Recirculation "A" Flow Excessive Detected | |
| P0403 | Exhaust Gas Recirculation "A" Control Circuit | |
| P0404 | Exhaust Gas Recirculation "A" Control Circuit Range/Performance | |
| P0405 | Exhaust Gas Recirculation Sensor "A" Circuit Low | |
| P0406 | Exhaust Gas Recirculation Sensor "A" Circuit High | |
| P0407 | Exhaust Gas Recirculation Sensor "B" Circuit Low | |
| P0408 | Exhaust Gas Recirculation Sensor "B" Circuit High | |
| P0409 | Exhaust Gas Recirculation Sensor "A" Circuit | |
| P040A | Exhaust Gas Recirculation Temperature Sensor "A" Circuit | |
| P040B | Exhaust Gas Recirculation Temperature Sensor "A" Circuit Range/Performance | |
| P040C | Exhaust Gas Recirculation Temperature Sensor "A" Circuit Low | |
| P040D | Exhaust Gas Recirculation Temperature Sensor "A" Circuit High | |
| P040E | Exhaust Gas Recirculation Temperature Sensor "A" Circuit Intermittent/Erratic | |
| P040F | Exhaust Gas Recirculation Temperature Sensor "A"/"B" Correlation | |
| P0410 | Secondary Air Injection System | |
| P0411 | Secondary Air Injection System Incorrect Flow Detected | |
| P0412 | Secondary Air Injection System Switching Valve "A" Circuit | |
| P0413 | Secondary Air Injection System Switching Valve "A" Circuit Open | |
| P0414 | Secondary Air Injection System Switching Valve "A" Circuit Shorted | |
| P0415 | Secondary Air Injection System Switching Valve "B" Circuit | |
| P0416 | Secondary Air Injection System Switching Valve "B" Circuit Open | |
| P0417 | Secondary Air Injection System Switching Valve "B" Circuit Shorted | |
| P0418 | Secondary Air Injection System Control "A" Circuit | |
| P0419 | Secondary Air Injection System Control "B" Circuit | |
| P041A | Exhaust Gas Recirculation Temperature Sensor "B" Circuit | |
| P041B | Exhaust Gas Recirculation Temperature Sensor "B" Circuit Range/Performance | |
| P041C | Exhaust Gas Recirculation Temperature Sensor "B" Circuit Low | |
| P041D | Exhaust Gas Recirculation Temperature Sensor "B" Circuit High | |
| P041E | Exhaust Gas Recirculation Temperature Sensor "B" Circuit Intermittent/Erratic | |
| P041F | Secondary Air Injection System Switching Valve "A" Circuit Low | |
| P0420 | Catalyst System Efficiency Below Threshold | Bank 1 |
| P0421 | Warm Up Catalyst Efficiency Below Threshold | Bank 1 |
| P0422 | Main Catalyst Efficiency Below Threshold | Bank 1 |
| P0423 | Heated Catalyst Efficiency Below Threshold | Bank 1 |
| P0424 | Heated Catalyst Temperature Below Threshold | Bank 1 |
| P0425 | Catalyst Temperature Sensor Circuit | Bank 1 Sensor 1 |
| P0426 | Catalyst Temperature Sensor Circuit Range/Performance | Bank 1 Sensor 1 |
| P0427 | Catalyst Temperature Sensor Circuit Low | Bank 1 Sensor 1 |
| P0428 | Catalyst Temperature Sensor Circuit High | Bank 1 Sensor 1 |
| P0429 | Catalyst Heater Control Circuit | Bank 1 |
| P042A | Catalyst Temperature Sensor Circuit | Bank 1 Sensor 2 |
| P042B | Catalyst Temperature Sensor Circuit Range/Performance | Bank 1 Sensor 2 |
| P042C | Catalyst Temperature Sensor Circuit Low | Bank 1 Sensor 2 |
| P042D | Catalyst Temperature Sensor Circuit High | Bank 1 Sensor 2 |
| P042E | Exhaust Gas Recirculation "A" Control Stuck Open | |
| P042F | Exhaust Gas Recirculation "A" Control Stuck Closed | |
| P0430 | Catalyst System Efficiency Below Threshold | Bank 2 |
| P0431 | Warm Up Catalyst Efficiency Below Threshold | Bank 2 |
| P0432 | Main Catalyst Efficiency Below Threshold | Bank 2 |
| P0433 | Heated Catalyst Efficiency Below Threshold | Bank 2 |
| P0434 | Heated Catalyst Temperature Below Threshold | Bank 2 |
| P0435 | Catalyst Temperature Sensor Circuit | Bank 2 Sensor 1 |
| P0436 | Catalyst Temperature Sensor Circuit Range/Performance | Bank 2 Sensor 1 |
| P0437 | Catalyst Temperature Sensor Circuit Low | Bank 2 Sensor 1 |
| P0438 | Catalyst Temperature Sensor Circuit High | Bank 2 Sensor 1 |
| P0439 | Catalyst Heater Control Circuit | Bank 2 |
| P043A | Catalyst Temperature Sensor Circuit | Bank 2 Sensor 2 |
| P043B | Catalyst Temperature Sensor Circuit Range/Performance | Bank 2 Sensor 2 |
| P043C | Catalyst Temperature Sensor Circuit Low | Bank 2 Sensor 2 |
| P043D | Catalyst Temperature Sensor Circuit High | Bank 2 Sensor 2 |
| P043E | Evaporative Emission System Leak Detection Reference Orifice | |
| P043F | Evaporative Emission System Leak Detection Reference Orifice High Flow | |
| P0440 | Evaporative Emission System | |
| P0441 | Evaporative Emission System Incorrect Purge Flow | |
| P0442 | Evaporative Emission System Leak Detected (small leak) | |
| P0443 | Evaporative Emission System Purge Control Valve Circuit | |
| P0444 | Evaporative Emission System Purge Control Valve Circuit Open | |
| P0445 | Evaporative Emission System Purge Control Valve Circuit Shorted | |
| P0446 | Evaporative Emission System Vent Control Circuit | |
| P0447 | Evaporative Emission System Vent Control Circuit Open | |
| P0448 | Evaporative Emission System Vent Control Circuit Shorted | |
| P0449 | Evaporative Emission System Vent Valve/Solenoid Circuit | |
| P044A | Exhaust Gas Recirculation Sensor "C" Circuit | |
| P044B | Exhaust Gas Recirculation Sensor "C" Circuit Range/Performance | |
| P044C | Exhaust Gas Recirculation Sensor "C" Circuit Low | |
| P044D | Exhaust Gas Recirculation Sensor "C" Circuit High | |
| P044E | Exhaust Gas Recirculation Sensor "C" Circuit Intermittent/Erratic | |
| P044F | Secondary Air Injection System Switching Valve "A" Circuit High | |
| P0450 | Evaporative Emission System Pressure Sensor/Switch | |
| P0451 | Evaporative Emission System Pressure Sensor/Switch Range/Performance | |
| P0452 | Evaporative Emission System Pressure Sensor/Switch Low | |
| P0453 | Evaporative Emission System Pressure Sensor/Switch High | |
| P0454 | Evaporative Emission System Pressure Sensor/Switch Intermittent | |
| P0455 | Evaporative Emission System Leak Detected (large leak) | |
| P0456 | Evaporative Emission System Leak Detected (very small leak) | |
| P0457 | Evaporative Emission System Leak Detected (fuel cap loose/off) | |
| P0458 | Evaporative Emission System Purge Control Valve Circuit Low | |
| P0459 | Evaporative Emission System Purge Control Valve Circuit High | |
| P045A | Exhaust Gas Recirculation "B" Control Circuit | |
| P045B | Exhaust Gas Recirculation "B" Control Circuit Range/Performance | |
| P045C | Exhaust Gas Recirculation "B" Control Circuit Low | |
| P045D | Exhaust Gas Recirculation "B" Control Circuit High | |
| P045E | Exhaust Gas Recirculation "B" Control Stuck Open | |
| P045F | Exhaust Gas Recirculation "B" Control Stuck Closed | |
| P0460 | Fuel Level Sensor "A" Circuit | |
| P0461 | Fuel Level Sensor "A" Circuit Range/Performance | |
| P0462 | Fuel Level Sensor "A" Circuit Low | |
| P0463 | Fuel Level Sensor "A" Circuit High | |
| P0464 | Fuel Level Sensor "A" Circuit Intermittent | |
| P0465 | EVAP Purge Flow Sensor Circuit | |
| P0466 | EVAP Purge Flow Sensor Circuit Range/Performance | |
| P0467 | EVAP Purge Flow Sensor Circuit Low | |
| P0468 | EVAP Purge Flow Sensor Circuit High | |
| P0469 | EVAP Purge Flow Sensor Circuit Intermittent | |
| P046A | Catalyst Temperature Sensor 1/2 Correlation | Bank 1 |
| P046B | Catalyst Temperature Sensor 1/2 Correlation | Bank 2 |
| P046C | Exhaust Gas Recirculation Sensor "A" Circuit Range/Performance | |
| P046D | Exhaust Gas Recirculation Sensor "A" Circuit Intermittent/Erratic | |
| P046E | Exhaust Gas Recirculation Sensor "B" Circuit Range/Performance | |
| P046F | Exhaust Gas Recirculation Sensor "B" Circuit Intermittent/Erratic | |
| P0470 | Exhaust Pressure Sensor "A" Circuit | |
| P0471 | Exhaust Pressure Sensor "A" Circuit Range/Performance | |
| P0472 | Exhaust Pressure Sensor "A" Circuit Low | |
| P0473 | Exhaust Pressure Sensor "A" Circuit High | |
| P0474 | Exhaust Pressure Sensor "A" Circuit Intermittent/Erratic | |
| P0475 | Exhaust Pressure Control Valve "A" | |
| P0476 | Exhaust Pressure Control Valve "A" Range/Performance | |
| P0477 | Exhaust Pressure Control Valve "A" Low | |
| P0478 | Exhaust Pressure Control Valve "A" High | |
| P0479 | Exhaust Pressure Control Valve "A" Intermittent | |
| P047A | Exhaust Pressure Sensor "B" Circuit | |
| P047B | Exhaust Pressure Sensor "B" Circuit Range/Performance | |
| P047C | Exhaust Pressure Sensor "B" Circuit Low | |
| P047D | Exhaust Pressure Sensor "B" Circuit High | |
| P047E | Exhaust Pressure Sensor "B" Circuit Intermittent/Erratic | |
| P047F | Exhaust Pressure Control Valve "A" Stuck Open | |
| P0480 | Fan 1 Control Circuit | |
| P0481 | Fan 2 Control Circuit | |
| P0482 | Fan 3 Control Circuit | |
| P0483 | Fan Rationality Check | |
| P0484 | Fan Circuit Over Current | |
| P0485 | Fan Power/Ground Circuit | |
| P0486 | Exhaust Gas Recirculation Sensor "B" Circuit | |
| P0487 | Exhaust Gas Recirculation Throttle Control Circuit "A" /Open | |
| P0488 | Exhaust Gas Recirculation Throttle Control Circuit "A" Range/Performance | |
| P0489 | Exhaust Gas Recirculation "A" Control Circuit Low | |
| P048A | Exhaust Pressure Control Valve "A" Stuck Closed | |
| P048B | Exhaust Pressure Control Valve Position Sensor/Switch Circuit | |
| P048C | Exhaust Pressure Control Valve Position Sensor/Switch Circuit Range/Performance | |
| P048D | Exhaust Pressure Control Valve Position Sensor/Switch Circuit Low | |
| P048E | Exhaust Pressure Control Valve Position Sensor/Switch Circuit High | |
| P048F | Exhaust Pressure Control Valve Position Sensor/Switch Circuit Intermittent/Erratic | |
| P0490 | Exhaust Gas Recirculation "A" Control Circuit High | |
| P0491 | Secondary Air Injection System Insufficient Flow | Bank 1 |
| P0492 | Secondary Air Injection System Insufficient Flow | Bank 2 |
| P0493 | Fan Overspeed | |
| P0494 | Fan Speed Low | |
| P0495 | Fan Speed High | |
| P0496 | Evaporative Emission System High Purge Flow | |
| P0497 | Evaporative Emission System Low Purge Flow | |
| P0498 | Evaporative Emission System Vent Valve Control Circuit Low | |
| P0499 | Evaporative Emission System Vent Valve Control Circuit High | |
| P049A | Exhaust Gas Recirculation "B" Flow | |
| P049B | Exhaust Gas Recirculation "B" Flow Insufficient Detected | |
| P049C | Exhaust Gas Recirculation "B" Flow Excessive Detected | |
| P049D | Exhaust Gas Recirculation "A" Control Position Exceeded Learning Limit | |
| P049E | Exhaust Gas Recirculation "B" Control Position Exceeded Learning Limit | |
| P049F | Exhaust Pressure Control Valve "B" | |
| P04A0 | Exhaust Pressure Control Valve "B" Range/Performance | |
| P04A1 | Exhaust Pressure Control Valve "B" Low | |
| P04A2 | Exhaust Pressure Control Valve "B" High | |
| P04A3 | Exhaust Pressure Control Valve " B" Intermittent | |
| P04A4 | Exhaust Pressure Control Valve "B" Stuck Open | |
| P04A5 | Exhaust Pressure Control Valve "B" Stuck Closed | |
| P04A6 | Exhaust Pressure Control Valve "B" Position Sensor/Switch Circuit | |
| P04A7 | Exhaust Pressure Control Valve "B" Position Sensor/Switch Circuit Range/Performance | |
| P04A8 | Exhaust Pressure Control Valve "B" Position Sensor/Switch Circuit Low | |
| P04A9 | Exhaust Pressure Control Valve "B" Position Sensor/Switch Circuit High | |
| P04AA | Exhaust Pressure Control Valve "B" Position Sensor/Switch Circuit Intermittent/Erratic | |
| P04AB – P04FF | ISO/SAE Reserved |