PowertrainP04DB
CautionSeverity: Caution - get it checked when you can
Crankcase Ventilation System Disconnected
Key terms: Catalytic converter: cleans the exhaust gases · EGR: exhaust gas recirculation, which cuts harmful gases · EVAP: the system that traps fuel vapour · Oxygen sensor: measures oxygen in the exhaust gas · SAE J2012: the standard generic code list · Powertrain: engine, transmission and emissions
1What it means in plain English
This range covers emissions control (EGR, EVAP, oxygen sensors and the catalytic converter), but some manufacturers also use P04 codes for oil-pressure, brake-fluid and coolant-level warnings.
2Common causes
- Clogged or faulty EGR valve
- EVAP system leak (hoses, canister, fuel cap)
- Faulty oxygen sensor
- Ageing catalytic converter
- Low oil, brake fluid or coolant (on some models)
- Wiring or connector fault
3Can I drive?
Do not assume this code is safe to drive. Check the description: if it names oil pressure, brake fluid, coolant, or a brake fault, stop safely and have it diagnosed before driving. Emissions-only codes (EGR, EVAP, catalyst) should still be checked before an emissions or roadworthiness inspection.
This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.
4Brand data 21
| Brand | Code | Description | System |
|---|---|---|---|
| Ashok Leyland CV | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| BAIC Motor | P04DB | Pressure Control Valve (PCV) pipeline fall-off Brand | Powertrain |
| Daewoo | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| DFFS | P04DB | Crankcase ventilation pipe disconnected Brand | Powertrain |
| DFFX | P04DB | crankcase ventilation line disconnected Brand | Powertrain |
| DFXK | P04DB | Crankcase ventilation system disconnected Brand | Powertrain |
| EOBD | P04DB | Sistem ventilasi karter terputus Brand | Powertrain |
| GM | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Holden | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Isuzu | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Land Rover | P04DB | Crankcase Ventilation System Disconnected Brand | Powertrain |
| Maserati | P04DB | Crankcase Ventilation System Disconnected Brand | Powertrain |
| Mitsubishi | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Opel | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Peugeot | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Porsche | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Saab | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| Subaru | P04DB | Crankcase Ventilation System Disconnected SAE | Powertrain |
| SWM Motor | P04DB | Positive crankcase ventilation (PCV) line disconnected Brand | Powertrain |
| Toyota | P04DB | Crankcase ventilation system disconnection Brand | Powertrain |
| Volkswagen | P04DB | Rate-based monitor “Crankcase breather system disconnected” counter for crankcase breather system Brand | Powertrain |
Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.
5Related codes
Browse Pxxx codes or P04Dxx codes.