P04E1
Crankcase Ventilation Hose Connection Sensor Circuit
A dedicated sensor monitors whether the PCV hose is fitted to its connector at the engine. The ECU detects a circuit fault on this sensor - cannot determine whether the hose is connected. Required by some emissions regulations to flag a disconnected PCV hose immediately.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: easy
Common causes
Ordered by how often each turns out to be the cause.
- Open in sensor circuitCommon
Parts involved
- PCV Hose Connection Sensor
P04E1 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.