OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Powertrain generic / SAE

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.

SystemPowertrain
Typegeneric / SAE
GroupP0
Range / number4 / E1

Possible causes

  • Open in sensor circuit high

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 60–250 €
  • Estimated time: 0.4–1.2 h
  • Component: pcv hose connection sensor
  • MIL / check engine light
  • emissions-relevant

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication