P04xx codes: Auxiliary emission controls (catalytic converter, EGR, EVAP)
256 powertrain trouble codes from P0400 to P04FF. They mostly involve the engine control module, sensor wiring, actuator wiring and EGR valve.
All P04xx codes
256 of these codes usually turn on the check engine light; 164 can often be fixed at home.
| Code | Meaning | Difficulty |
|---|---|---|
| P0400 | EGR A Flow | Medium |
| P0401 | EGR A Flow Insufficient Detected | Medium |
| P0402 | EGR A Flow Excessive Detected | Medium |
| P0403 | EGR A Control Circuit/Open | Easy |
| P0404 | EGR A Control Circuit Range/Performance | Medium |
| P0405 | EGR Sensor A Circuit Low | Easy |
| P0406 | EGR Sensor A Circuit High | Easy |
| P0407 | EGR Sensor B Circuit Low | Easy |
| P0408 | EGR Sensor B Circuit High | Easy |
| P0409 | EGR Sensor A Circuit | Easy |
| P040A | EGR Temperature Sensor A Circuit | Easy |
| P040B | EGR Temperature Sensor A Circuit Range/Performance | Easy |
| P040C | EGR Temperature Sensor A Circuit Low | Easy |
| P040D | EGR Temperature Sensor A Circuit High | Easy |
| P040E | EGR Temperature Sensor A Circuit Intermittent/Erratic | Easy |
| P040F | EGR Temperature Sensor A/B Correlation | Easy |
| P0410 | AIR System A | Medium |
| P0411 | AIR System A Incorrect Flow Detected | Medium |
| P0412 | AIR System Switching Valve A Circuit | Easy |
| P0413 | AIR System Switching Valve A Circuit Open | Easy |
| P0414 | AIR System Switching Valve A Circuit Shorted | Easy |
| P0415 | AIR System Switching Valve B Circuit | Easy |
| P0416 | AIR System Switching Valve B Circuit Open | Easy |
| P0417 | AIR System Switching Valve B Circuit Shorted | Easy |
| P0418 | AIR System Control A Circuit | Easy |
| P0419 | AIR System Control B Circuit | Easy |
| P041A | EGR Temperature Sensor B Circuit | Easy |
| P041B | EGR Temperature Sensor B Circuit Range/Performance | Easy |
| P041C | EGR Temperature Sensor B Circuit Low | Easy |
| P041D | EGR Temperature Sensor B Circuit High | Easy |
| P041E | EGR Temperature Sensor B Circuit Intermittent/Erratic | Easy |
| P041F | AIR System Switching Valve A Circuit Low | Easy |
| P0420 | Catalyst System Efficiency Below Threshold Bank 1 | Medium |
| P0421 | Catalyst 1 Efficiency Below Threshold Bank 1 | Medium |
| P0422 | Catalyst 2 Efficiency Below Threshold Bank 1 | Medium |
| P0423 | Heated Catalyst Efficiency Below Threshold Bank 1 | Hard |
| P0424 | Heated Catalyst Temperature Below Threshold Bank 1 | Hard |
| P0425 | Catalyst Temperature Sensor Circuit Bank 1 Sensor 1 | Medium |
| P0426 | Catalyst Temperature Sensor Circuit Range/Performance Bank 1 Sensor 1 | Medium |
| P0427 | Catalyst Temperature Sensor Circuit Low Bank 1 Sensor 1 | Medium |
| P0428 | Catalyst Temperature Sensor Circuit High Bank 1 Sensor 1 | Medium |
| P0429 | Catalyst Heater Control Circuit/Open Bank 1 | Medium |
| P042A | Catalyst Temperature Sensor Circuit Bank 1 Sensor 2 | Medium |
| P042B | Catalyst Temperature Sensor Circuit Range/Performance Bank 1 Sensor 2 | Medium |
| P042C | Catalyst Temperature Sensor Circuit Low Bank 1 Sensor 2 | Medium |
| P042D | Catalyst Temperature Sensor Circuit High Bank 1 Sensor 2 | Medium |
| P042E | EGR A Control Stuck Open | Medium |
| P042F | EGR A Control Stuck Closed | Medium |
| P0430 | Catalyst System Efficiency Below Threshold Bank 2 | Medium |
| P0431 | Catalyst 1 Efficiency Below Threshold Bank 2 | Medium |
| P0432 | Catalyst 2 Efficiency Below Threshold Bank 2 | Medium |
| P0433 | Heated Catalyst Efficiency Below Threshold Bank 2 | Hard |
| P0434 | Heated Catalyst Temperature Below Threshold Bank 2 | Hard |
| P0435 | Catalyst Temperature Sensor Circuit Bank 2 Sensor 1 | Medium |
| P0436 | Catalyst Temperature Sensor Circuit Range/Performance Bank 2 Sensor 1 | Medium |
| P0437 | Catalyst Temperature Sensor Circuit Low Bank 2 Sensor 1 | Medium |
| P0438 | Catalyst Temperature Sensor Circuit High Bank 2 Sensor 1 | Medium |
| P0439 | Catalyst Heater Control Circuit/Open Bank 2 | Medium |
| P043A | Catalyst Temperature Sensor Circuit Bank 2 Sensor 2 | Medium |
| P043B | Catalyst Temperature Sensor Circuit Range/Performance Bank 2 Sensor 2 | Medium |
| P043C | Catalyst Temperature Sensor Circuit Low Bank 2 Sensor 2 | Medium |
| P043D | Catalyst Temperature Sensor Circuit High Bank 2 Sensor 2 | Medium |
| P043E | EVAP System Leak Detection Reference Orifice Low Flow | Medium |
| P043F | EVAP System Leak Detection Reference Orifice High Flow | Medium |
| P0440 | EVAP System | Medium |
| P0441 | EVAP System Incorrect Purge Flow | Easy |
| P0442 | EVAP System Leak Detected (small leak) | Medium |
| P0443 | EVAP System Purge Control Valve A Circuit | Easy |
| P0444 | EVAP System Purge Control Valve A Circuit Open | Easy |
| P0445 | EVAP System Purge Control Valve A Circuit Shorted | Easy |
| P0446 | EVAP System Vent Control Circuit | Medium |
| P0447 | EVAP System Vent Control Circuit Open | Easy |
| P0448 | EVAP System Vent Control Circuit Shorted | Medium |
| P0449 | EVAP System Vent Valve Control Circuit/Open | Easy |
| P044A | EGR Sensor C Circuit | Easy |
| P044B | EGR Sensor C Circuit Range/Performance | Easy |
| P044C | EGR Sensor C Circuit Low | Easy |
| P044D | EGR Sensor C Circuit High | Easy |
| P044E | EGR Sensor C Circuit Intermittent/Erratic | Easy |
| P044F | AIR System Switching Valve A Circuit High | Easy |
| P0450 | EVAP System Pressure Sensor/Switch A Circuit | Medium |
| P0451 | EVAP System Pressure Sensor/Switch A Circuit Range/Performance | Medium |
| P0452 | EVAP System Pressure Sensor/Switch A Circuit Low | Medium |
| P0453 | EVAP System Pressure Sensor/Switch A Circuit High | Medium |
| P0454 | EVAP System Pressure Sensor/Switch A Circuit Intermittent | Medium |
| P0455 | EVAP System Leak Detected - Large Leak | Easy |
| P0456 | EVAP System Leak Detected (very small leak) | Medium |
| P0457 | EVAP System Leak Detected (fuel cap loose/off) | Easy |
| P0458 | EVAP System Purge Control Valve A Circuit Low | Easy |
| P0459 | EVAP System Purge Control Valve A Circuit High | Easy |
| P045A | EGR B Control Circuit | Medium |
| P045B | EGR B Control Circuit Range/Performance | Medium |
| P045C | EGR B Control Circuit Low | Medium |
| P045D | EGR B Control Circuit High | Medium |
| P045E | EGR B Control Stuck Open | Medium |
| P045F | EGR B Control Stuck Closed | Medium |
| P0460 | Fuel Level Sensor A Circuit | Medium |
| P0461 | Fuel Level Sensor A Circuit Range/Performance | Medium |
| P0462 | Fuel Level Sensor A Circuit Low | Medium |
| P0463 | Fuel Level Sensor A Circuit High | Medium |
| P0464 | Fuel Level Sensor A Circuit Intermittent | Medium |
| P0465 | EVAP Purge Flow Sensor Circuit | Medium |
| P0466 | EVAP Purge Flow Sensor Circuit Range/Performance | Medium |
| P0467 | EVAP Purge Flow Sensor Circuit Low | Medium |
| P0468 | EVAP Purge Flow Sensor Circuit High | Medium |
| P0469 | EVAP Purge Flow Sensor Circuit Intermittent | Medium |
| P046A | Catalyst Temperature Sensor 1/2 Correlation Bank 1 | Medium |
| P046B | Catalyst Temperature Sensor 1/2 Correlation Bank 2 | Medium |
| P046C | EGR Sensor A Circuit Range/Performance | Medium |
| P046D | EGR Sensor A Circuit Intermittent/Erratic | Easy |
| P046E | EGR Sensor B Circuit Range/Performance | Easy |
| P046F | EGR Sensor B Circuit Intermittent/Erratic | Easy |
| P0470 | Exhaust Pressure Sensor A Circuit | Medium |
| P0471 | Exhaust Pressure Sensor A Circuit Range/Performance | Medium |
| P0472 | Exhaust Pressure Sensor A Circuit Low | Medium |
| P0473 | Exhaust Pressure Sensor A Circuit High | Medium |
| P0474 | Exhaust Pressure Sensor A Circuit Intermittent/Erratic | Medium |
| P0475 | Exhaust Pressure Control Valve A | Medium |
| P0476 | Exhaust Pressure Control Valve A Range/Performance | Medium |
| P0477 | Exhaust Pressure Control Valve A Low | Medium |
| P0478 | Exhaust Pressure Control Valve A High | Medium |
| P0479 | Exhaust Pressure Control Valve A Intermittent | Medium |
| P047A | Exhaust Pressure Sensor B Circuit | Medium |
| P047B | Exhaust Pressure Sensor B Circuit Range/Performance | Medium |
| P047C | Exhaust Pressure Sensor B Circuit Low | Medium |
| P047D | Exhaust Pressure Sensor B Circuit High | Medium |
| P047E | Exhaust Pressure Sensor B Circuit Intermittent/Erratic | Medium |
| P047F | Exhaust Pressure Control Valve A Stuck Open | Medium |
| P0480 | Fan 1 Control Circuit | Medium |
| P0481 | Fan 2 Control Circuit | Medium |
| P0482 | Fan 3 Control Circuit | Medium |
| P0483 | Fan Rationality Check | Medium |
| P0484 | Fan Circuit Current High | Medium |
| P0485 | Fan Power/Ground Circuit | Medium |
| P0486 | EGR Sensor B Circuit | Medium |
| P0487 | EGR Throttle Control Circuit A/Open | Medium |
| P0488 | EGR Throttle Control Circuit A Range/Performance | Medium |
| P0489 | EGR A Control Circuit Low | Medium |
| P048A | Exhaust Pressure Control Valve A Stuck Closed | Medium |
| P048B | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit | Medium |
| P048C | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Range/Performance | Medium |
| P048D | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Low | Medium |
| P048E | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit High | Medium |
| P048F | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Intermittent/Erratic | Medium |
| P0490 | EGR A Control Circuit High | Medium |
| P0491 | AIR System Insufficient Flow Bank 1 | Medium |
| P0492 | AIR System Insufficient Flow Bank 2 | Medium |
| P0493 | Fan Overspeed | Medium |
| P0494 | Fan 1 Underspeed | Medium |
| P0495 | Fan 1 Overspeed | Medium |
| P0496 | EVAP System High Purge Flow | Easy |
| P0497 | EVAP System Low Purge Flow | Medium |
| P0498 | EVAP System Vent Valve Control Circuit Low | Easy |
| P0499 | EVAP System Vent Valve Control Circuit High | Easy |
| P049A | EGR B Flow | Hard |
| P049B | EGR B Flow Insufficient Detected | Hard |
| P049C | EGR B Flow Excessive Detected | Hard |
| P049D | EGR A Control Position Exceeded Learning Limit | Medium |
| P049E | EGR B Control Position Exceeded Learning Limit | Hard |
| P049F | Exhaust Pressure Control Valve B | Medium |
| P04A0 | Exhaust Pressure Control Valve B Range/Performance | Medium |
| P04A1 | Exhaust Pressure Control Valve B Low | Medium |
| P04A2 | Exhaust Pressure Control Valve B High | Medium |
| P04A3 | Exhaust Pressure Control Valve B Intermittent | Medium |
| P04A4 | Exhaust Pressure Control Valve B Stuck Open | Medium |
| P04A5 | Exhaust Pressure Control Valve B Stuck Closed | Medium |
| P04A6 | Exhaust Pressure Control Valve B Position Sensor/Switch Circuit | Medium |
| P04A7 | Exhaust Pressure Control Valve B Position Sensor/Switch Circuit Range/Performance | Medium |
| P04A8 | Exhaust Pressure Control Valve B Position Sensor/Switch Circuit Low | Medium |
| P04A9 | Exhaust Pressure Control Valve B Position Sensor/Switch Circuit High | Medium |
| P04AA | Exhaust Pressure Control Valve B Position Sensor/Switch Circuit Intermittent/Erratic | Medium |
| P04AB | EVAP System Purge Control Valve B Circuit/Open | Easy |
| P04AC | EVAP System Purge Control Valve B Circuit Low | Easy |
| P04AD | EVAP System Purge Control Valve B Circuit High | Easy |
| P04AE | EVAP System Purge Control Valve B Performance/Stuck Open | Medium |
| P04AF | EVAP System Purge Control Valve B Stuck Closed | Medium |
| P04B0 | Refueling Vapor Control Valve Circuit/Open | Medium |
| P04B1 | Refueling Vapor Control Valve Circuit Low | Medium |
| P04B2 | Refueling Vapor Control Valve Circuit High | Medium |
| P04B3 | Refueling Vapor Control Valve Performance/Stuck Open | Medium |
| P04B4 | Refueling Vapor Control Valve Stuck Closed | Medium |
| P04B5 | Fuel Fill Door Stuck Open | Easy |
| P04B6 | Fuel Fill Door Stuck Closed | Easy |
| P04B7 | Fuel Fill Door Position Sensor/Switch Circuit Intermittent/Erratic | Easy |
| P04B8 | Fuel Fill Door Position Sensor/Switch Circuit | Easy |
| P04B9 | Fuel Fill Door Position Sensor/Switch Circuit Low | Easy |
| P04BA | Fuel Fill Door Position Sensor/Switch Circuit High | Easy |
| P04BB | Fuel Fill Door Lock Control Circuit/Open | Medium |
| P04BC | Fuel Fill Door Lock Control Range/Performance | Medium |
| P04BD | Fuel Fill Door Lock Control Circuit Low | Medium |
| P04BE | Fuel Fill Door Lock Control Circuit High | Medium |
| P04BF | Fuel Fill Door Unlock Control Circuit/Open | Medium |
| P04C0 | Fuel Fill Door Unlock Control Range/Performance | Medium |
| P04C1 | Fuel Fill Door Unlock Control Circuit Low | Medium |
| P04C2 | Fuel Fill Door Unlock Control Circuit High | Medium |
| P04C3 | Fuel Fill Door Lock Position Sensor/Switch Circuit | Medium |
| P04C4 | Fuel Fill Door Lock Position Sensor/Switch Circuit Range/Performance | Medium |
| P04C5 | Fuel Fill Door Lock Position Sensor/Switch Circuit Low | Medium |
| P04C6 | Fuel Fill Door Lock Position Sensor/Switch Circuit High | Medium |
| P04C7 | Fuel Fill Door Lock Position Sensor/Switch Circuit Intermittent/Erratic | Medium |
| P04C8 | Fuel Fill Door Open Request Sensor/Switch Circuit | Easy |
| P04C9 | Fuel Fill Door Open Request Sensor/Switch Performance/Stuck Off | Easy |
| P04CA | Fuel Fill Door Open Request Sensor/Switch Circuit Low | Easy |
| P04CB | Fuel Fill Door Open Request Sensor/Switch Circuit High | Easy |
| P04CC | Fuel Fill Door Open Request Sensor/Switch Circuit Intermittent/Erratic | Easy |
| P04CD | Fuel Fill Door Open Request Sensor/Switch Stuck On | Easy |
| P04CE | EGR Temperature Sensor C Circuit | Medium |
| P04CF | EGR Temperature Sensor C Circuit Range/Performance | Medium |
| P04D0 | EGR Temperature Sensor C Circuit Low | Medium |
| P04D1 | EGR Temperature Sensor C Circuit High | Medium |
| P04D2 | EGR Temperature Sensor C Circuit Intermittent/Erratic | Medium |
| P04D3 | Exhaust Brake Input Circuit | Medium |
| P04D4 | Exhaust Brake Input Circuit Range/Performance | Medium |
| P04D5 | Exhaust Brake Input Circuit Low | Medium |
| P04D6 | Exhaust Brake Input Circuit High | Medium |
| P04D7 | Exhaust Brake Input Circuit Intermittent/Erratic | Medium |
| P04D8 | Excessive Time To Enter Closed Loop EGR Control | Medium |
| P04D9 | Closed Loop EGR Control At Limit - Flow Too Low | Medium |
| P04DA | Closed Loop EGR Control At Limit - Flow Too High | Medium |
| P04DB | Crankcase Ventilation System Disconnected | Easy |
| P04DC | Fuel Fill Door Position Sensor/Switch Circuit Range/Performance | Easy |
| P04DD | Cold Start EGR A Flow Insufficient Detected | Medium |
| P04DE | Cold Start EGR A Flow Excessive Detected | Medium |
| P04DF | EVAP System Purge Control Valve A Performance/Stuck Open | Easy |
| P04E0 | EVAP System Purge Control Valve A Stuck Closed | Easy |
| P04E1 | Crankcase Ventilation Hose Connection Sensor Circuit | Easy |
| P04E2 | Crankcase Ventilation Hose Connection Sensor Circuit Low | Easy |
| P04E3 | Crankcase Ventilation Hose Connection Sensor Circuit High | Easy |
| P04E4 | Crankcase Ventilation Hose Connection Sensor Circuit Intermittent/Erratic | Easy |
| P04E5 | EGR Temperature Sensor D Circuit | Medium |
| P04E6 | EGR Temperature Sensor D Circuit Range/Performance | Medium |
| P04E7 | EGR Temperature Sensor D Circuit Low | Medium |
| P04E8 | EGR Temperature Sensor D Circuit High | Medium |
| P04E9 | EGR Temperature Sensor D Circuit Intermittent/Erratic | Medium |
| P04EA | EVAP System Small Leak Detected - Fuel Tank Side | Medium |
| P04EB | EVAP System Small Leak Detected - Fresh Air Side | Medium |
| P04EC | EVAP System Large Leak Detected - Fuel Tank Side | Easy |
| P04ED | EVAP System Large Leak Detected - Fresh Air Side | Medium |
| P04EE | EVAP System Very Small Leak Detected - Fuel Tank Side | Easy |
| P04EF | EVAP System Very Small Leak Detected - Fresh Air Side | Medium |
| P04F0 | EVAP System High Load Purge Line A Performance | Medium |
| P04F1 | EVAP System Purge Line Performance | Easy |
| P04F2 | Catalyst Heater Supply Voltage Bank 1 | Medium |
| P04F3 | Catalyst Heater Supply Voltage Bank 2 | Medium |
| P04F4 | Catalyst Heater Circuit Low Bank 1 | Medium |
| P04F5 | Catalyst Heater Circuit Low Bank 2 | Medium |
| P04F6 | Catalyst Heater Circuit High Bank 1 | Medium |
| P04F7 | Catalyst Heater Circuit High Bank 2 | Medium |
| P04F8 | Catalyst Heater Circuit Intermittent Bank 1 | Medium |
| P04F9 | Catalyst Heater Circuit Intermittent Bank 2 | Medium |
| P04FA | EGR A Control Temperature Too High | Medium |
| P04FB | Crankcase Ventilation Hose Connection Sensor Range/Performance | Easy |
| P04FC | Crankcase Ventilation System Performance | Medium |
| P04FD | EGR Actuator A Control Processor Performance | Hard |
| P04FE | Catalyst Heater Circuit Performance Bank 1 | Hard |
| P04FF | Catalyst Heater Circuit Performance Bank 2 | Hard |