Fault codes P04xx: emissions control
These codes concern the systems that limit pollution: exhaust gas recirculation (EGR), catalytic converter, fuel vapor circuit (canister), secondary air injection. They often do not prevent driving, but may cause problems at the vehicle inspection.
Official codes: 256, from smallest to largest. Tap a code to get a direct link to share.
| Code | Meaning |
|---|---|
| P0400 | Exhaust Gas Recirculation Flow Malfunction |
| P0401 | Exhaust Gas Recirculation Flow Insufficient Detected |
| P0402 | Exhaust Gas Recirculation Flow Excessive Detected |
| P0403 | EGR Control Circuit |
| P0404 | EGR Range/Performance |
| P0405 | Exhaust Gas Recirculation Sensor "A" Circuit Low |
| P0406 | Exhaust Gas Recirculation Sensor "A" Circuit High |
| P0407 | EGR Sensor B Circuit Low |
| P0408 | Exhaust Gas Recirculation Sensor "B" Circuit Low |
| P0409 | Exhaust Gas Recirculation Sensor "B" Circuit High |
| P040A | EGR Temperature Sensor A Circuit |
| P040B | EGR Temperature Sensor A Circuit Range/Performance |
| P040C | EGR Temperature Sensor A Circuit Low |
| P040D | EGR Temperature Sensor A Circuit High |
| P040E | EGR Temperature Sensor A Circuit Intermittent/Erratic |
| P040F | EGR Temperature Sensor A/B Correlation |
| P0410 | Secondary Air Injection System Malfunction |
| P0411 | Secondary Air Injection System Incorrect Flow |
| 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 Relay "A" Circuit Malfunction |
| P0419 | Secondary Air Injection System Control B Circuit |
| P041A | EGR Temperature Sensor B Circuit |
| P041B | EGR Temperature Sensor B Circuit Range/Performance |
| P041C | EGR Temperature Sensor B Circuit Low |
| P041D | EGR Temperature Sensor B Circuit High |
| P041E | EGR 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 (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/Open (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 | EGR A Control Stuck Open |
| P042F | EGR 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/Open (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 | EVAP System Leak Detection Reference Orifice Low Flow |
| P043F | EVAP System Leak Detection Reference Orifice High Flow |
| P0440 | Evaporative Emission Control System Malfunction |
| 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 Purge Control Valve Circuit Open |
| P0445 | Evaporative Emission System Purge Control Valve Circuit Shorted |
| P0446 | Evaporative Emission Vent Control Circuit Malfunction |
| P0447 | Evaporative Emission System Vent Control Circuit Open |
| P0448 | EVAP System Vent Control Circuit Shorted |
| P0449 | Evaporative Emission System Vent Valve/Solenoid Circuit Malfunction |
| P044A | EGR Sensor C Circuit |
| P044B | EGR Sensor C Circuit Range/Performance |
| P044C | EGR Sensor C Circuit Low |
| P044D | EGR Sensor C Circuit High |
| P044E | EGR Sensor C Circuit Intermittent/Erratic |
| P044F | Secondary Air Injection System Switching Valve A Circuit High |
| P0450 | EVAP System Pressure Sensor/Switch A Circuit |
| P0451 | Evaporative Emission System Pressure Sensor Range/Performance |
| P0452 | Evaporative Emission System Pressure Sensor Low Input |
| P0453 | Evaporative Emission System Pressure Sensor High Input |
| P0454 | EVAP System Pressure Sensor/Switch A Circuit 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 | EVAP System Purge Control Valve A Circuit Low |
| P0459 | EVAP System Purge Control Valve A Circuit High |
| P045A | EGR B Control Circuit |
| P045B | EGR B Control Circuit Range/Performance |
| P045C | EGR B Control Circuit Low |
| P045D | EGR B Control Circuit High |
| P045E | EGR B Control Stuck Open |
| P045F | EGR 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 | EGR Sensor A Circuit Range/Performance |
| P046D | EGR Sensor A Circuit Intermittent/Erratic |
| P046E | EGR Sensor B Circuit Range/Performance |
| P046F | EGR 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 | Cooling Fan 1 Control Circuit |
| P0481 | Cooling Fan 2 Control Circuit |
| P0482 | Cooling Fan 3 Control Circuit Malfunction |
| P0483 | Cooling Fan Rationality Check |
| P0484 | Cooling Fan Current Too High |
| P0485 | Cooling Fan Power/Ground Circuit |
| P0486 | EGR Sensor B Circuit |
| P0487 | EGR Throttle Control Circuit A/Open |
| P0488 | EGR Throttle Control Circuit A Range/Performance |
| P0489 | EGR A Control Circuit Low |
| P048A | Exhaust Pressure Control Valve A Stuck Closed |
| P048B | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit |
| P048C | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Range/Performance |
| P048D | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Low |
| P048E | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit High |
| P048F | Exhaust Pressure Control Valve A Position Sensor/Switch Circuit Intermittent/Erratic |
| P0490 | EGR 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 1 Underspeed |
| P0495 | Fan 1 Overspeed |
| P0496 | Evaporative Emission System High Purge Flow |
| P0497 | EVAP System Low Purge Flow |
| P0498 | EVAP System Vent Valve Control Circuit Low |
| P0499 | EVAP System Vent Valve Control Circuit High |
| P049A | EGR B Flow |
| P049B | EGR B Flow Insufficient Detected |
| P049C | EGR B Flow Excessive Detected |
| P049D | EGR A Control Position Exceeded Learning Limit |
| P049E | EGR B Control Position Exceeded Learning Limit |
| P049F | Exhaust Pressure Control Valve B |
| P04A0 | Exhaust Pressure Control Valve B Range or 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 Circuit |
| P04A7 | Exhaust Pressure Control Valve B Position Sensor Circuit Range or Performance |
| P04A8 | Exhaust Pressure Control Valve B Position Sensor Circuit Low |
| P04A9 | Exhaust Pressure Control Valve B Position Sensor Circuit High |
| P04AA | Exhaust Pressure Control Valve B Position Sensor Circuit Intermittent or Erratic |
| P04AB | EVAP System Purge Control Valve B Circuit Open |
| P04AC | EVAP System Purge Control Valve B Circuit Low |
| P04AD | EVAP System Purge Control Valve B Circuit High |
| P04AE | EVAP System Purge Control Valve B Performance Stuck Open |
| P04AF | EVAP System Purge Control Valve B Stuck Closed |
| P04B0 | Refueling Vapor Control Valve Circuit Open |
| P04B1 | Refueling Vapor Control Valve Circuit Low |
| P04B2 | Refueling Vapor Control Valve Circuit High |
| P04B3 | Refueling Vapor Control Valve Performance Stuck Open |
| P04B4 | Refueling Vapor Control Valve Stuck Closed |
| P04B5 | Fuel Fill Door Stuck Open |
| P04B6 | Fuel Fill Door Stuck Closed |
| P04B7 | Fuel Fill Door Position Sensor Circuit Intermittent or Erratic |
| P04B8 | Fuel Fill Door Position Sensor Circuit |
| P04B9 | Fuel Fill Door Position Sensor Circuit Low |
| P04BA | Fuel Fill Door Position Sensor Circuit High |
| P04BB | Fuel Fill Door Lock Control Circuit Open |
| P04BC | Fuel Fill Door Lock Control Range or Performance |
| P04BD | Fuel Fill Door Lock Control Circuit Low |
| P04BE | Fuel Fill Door Lock Control Circuit High |
| P04BF | Fuel Fill Door Unlock Control Circuit Open |
| P04C0 | Fuel Fill Door Unlock Control Range or Performance |
| P04C1 | Fuel Fill Door Unlock Control Circuit Low |
| P04C2 | Fuel Fill Door Unlock Control Circuit High |
| P04C3 | Fuel Fill Door Lock Position Sensor Circuit |
| P04C4 | Fuel Fill Door Lock Position Sensor Circuit Range or Performance |
| P04C5 | Fuel Fill Door Lock Position Sensor Circuit Low |
| P04C6 | Fuel Fill Door Lock Position Sensor Circuit High |
| P04C7 | Fuel Fill Door Lock Position Sensor Circuit Intermittent or Erratic |
| P04C8 | Fuel Fill Door Open Request Sensor or Switch Circuit |
| P04C9 | Fuel Fill Door Open Request Performance Stuck Off |
| P04CA | Fuel Fill Door Open Request Sensor or Switch Circuit Low |
| P04CB | Fuel Fill Door Open Request Sensor or Switch Circuit High |
| P04CC | Fuel Fill Door Open Request Sensor or Switch Circuit Intermittent or Erratic |
| P04CD | Fuel Fill Door Open Request Sensor or Switch Stuck On |
| P04CE | EGR Temperature Sensor C Circuit |
| P04CF | EGR Temperature Sensor C Circuit Range or Performance |
| P04D0 | EGR Temperature Sensor C Circuit Low |
| P04D1 | EGR Temperature Sensor C Circuit High |
| P04D2 | EGR Temperature Sensor C Circuit Intermittent or Erratic |
| P04D3 | Exhaust Brake Input Circuit |
| P04D4 | Exhaust Brake Input Circuit Range or Performance |
| P04D5 | Exhaust Brake Input Circuit Low |
| P04D6 | Exhaust Brake Input Circuit High |
| P04D7 | Exhaust Brake Input Circuit Intermittent or Erratic |
| P04D8 | Excessive Time To Enter Closed Loop EGR Control |
| P04D9 | Closed Loop EGR Control At Limit Flow Too Low |
| P04DA | Closed Loop EGR Control At Limit Flow Too High |
| P04DB | Crankcase Ventilation System Disconnected |
| P04DC | Fuel Fill Door Position Sensor Circuit Range or Performance |
| P04DD | Cold Start EGR A Flow Insufficient Detected |
| P04DE | Cold Start EGR A Flow Excessive Detected |
| P04DF | EVAP System Purge Control Valve A Performance Stuck Open |
| P04E0 | EVAP System Purge Control Valve A Stuck Closed |
| P04E1 | Crankcase Ventilation Hose Connection Sensor Circuit |
| P04E2 | Crankcase Ventilation Hose Connection Sensor Circuit Low |
| P04E3 | Crankcase Ventilation Hose Connection Sensor Circuit High |
| P04E4 | Crankcase Ventilation Hose Connection Sensor Circuit Intermittent or Erratic |
| P04E5 | EGR Temperature Sensor D Circuit |
| P04E6 | EGR Temperature Sensor D Circuit Range or Performance |
| P04E7 | EGR Temperature Sensor D Circuit Low |
| P04E8 | EGR Temperature Sensor D Circuit High |
| P04E9 | EGR Temperature Sensor D Circuit Intermittent or Erratic |
| P04EA | EVAP System Small Leak Detected Fuel Tank Side |
| P04EB | EVAP System Small Leak Detected Fresh Air Side |
| P04EC | EVAP System Large Leak Detected Fuel Tank Side |
| P04ED | EVAP System Large Leak Detected Fresh Air Side |
| P04EE | EVAP System Very Small Leak Detected Fuel Tank Side |
| P04EF | EVAP System Very Small Leak Detected Fresh Air Side |
| P04F0 | EVAP System High Load Purge Line A Performance |
| P04F1 | EVAP System Purge Line Performance |
| P04F2 | Catalyst Heater Supply Voltage Bank 1 |
| P04F3 | Catalyst Heater Supply Voltage Bank 2 |
| P04F4 | Catalyst Heater Circuit Low Bank 1 |
| P04F5 | Catalyst Heater Circuit Low Bank 2 |
| P04F6 | Catalyst Heater Circuit High Bank 1 |
| P04F7 | Catalyst Heater Circuit High Bank 2 |
| P04F8 | Catalyst Heater Circuit Intermittent Bank 1 |
| P04F9 | Catalyst Heater Circuit Intermittent Bank 2 |
| P04FA | EGR A Control Temperature Too High |
| P04FB | Crankcase Ventilation Hose Connection Sensor Range or Performance |
| P04FC | Crankcase Ventilation System Performance |
| P04FD | EGR Actuator A Control Processor Performance |
| P04FE | Catalyst Heater Circuit Performance Bank 1 |
| P04FF | Catalyst Heater Circuit Performance Bank 2 |
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Official meanings: OBDex (public domain, CC0). Manufacturer codes: dtc-database (MIT license), probable meanings not verified by the manufacturers. The same meaning can vary depending on the model: always have a diagnosis confirmed by a professional.