What it means
Same as P04E1 with the signal voltage below the plausible range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The crankcase ventilation hose connection sensor signals whether the PCV hose is fitted at the engine, and the control module monitors its electrical signal. P04E2 sets when that signal is below the plausible range, often because it is shorted to ground or its connection has excessive resistance.
Common causes
Most likely first.
- Signal shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Hose-connection status may be unavailable or incorrect
- Crankcase ventilation warning may appear
How to diagnose it
- Use scan-tool data and freeze-frame information to confirm the hose connection signal is low when the fault is present.
- Check that the PCV hose is seated, then inspect the sensor connector for moisture, corrosion, pushed-back pins, or poor terminal contact.
- Trace the sensor signal wire for chafing or damage where it could contact ground, paying attention to harness bends and nearby engine components.
- While watching the signal, gently wiggle the connector and harness to see whether movement changes the reading.
- Test the signal circuit for a short to ground and test the sensor against the manufacturer's specification.
Common fixes
- Clean and secure corroded or loose sensor connector terminals.
- Repair chafed signal wiring that is contacting ground.
- Repair damaged connector pins or restore a pushed-back terminal.
- Replace the hose connection sensor if the wiring is sound and the sensor output remains below specification.
Can I keep driving?
If the PCV hose is connected and the engine runs normally, cautious driving is generally possible while you arrange repair. Confirm the hose is secure, since a disconnected hose can affect engine operation and emissions.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.