P04E4Crankcase Ventilation Hose Connection Sensor Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- The crankcase ventilation (PCV) system routes blow-by gas from the crankcase into the intake; CARB requires a disconnection between crankcase and intake to be detected. GM's 2.0-litre LSY has a pressure sensor in the PCV hose: with the hose connected it must see a pressure drop that grows with air flow, plus pressure pulses from the pistons. Ford reports the same sensor type as crankcase pressure sensor A (P051A ff). P04E4 means the sensor signal jumps or drops out briefly – usually a loose contact, a chafed wire or a measuring port blocked by oil sludge or ice. The disconnection check P04DB is then suspended or may report falsely. No manufacturer document available to us uses this code; the description follows the GM sibling codes P04E2/P04E3 and CARB.
- What you may notice
- Check engine light on
- Disconnection check P04DB does not run
- Usually no change in driving
- Likely causes
- LikelyLoose contact at the sensor connector
- PossibleChafed wire with intermittent short
- PossibleSensor faulty or measuring port blocked (oil sludge, ice)
- RareEngine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €50 – €250
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.