What it means
Same as P05D8 with the control line shorted to ground. 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 PCV regulator valve controls crankcase ventilation flow, while the engine control module monitors its electrical control circuit. This code sets when the control line is pulled low, commonly by a short to ground, so the module detects a lower circuit level than expected.
Common causes
Most likely first.
- Control line shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light may illuminate
- Crankcase ventilation or emissions fault may be indicated
How to diagnose it
- Check freeze-frame data and PCV-related live data for when the fault occurred and whether the valve command or feedback changes with the code.
- Inspect the PCV regulator valve connector and harness for moisture, corrosion, backed-out pins, or insulation rubbed through to ground.
- With the circuit monitored, gently move the harness and connector to see whether the low reading or code changes.
- Use the vehicle wiring diagram to check the control wire for an unintended connection to ground and inspect the connector terminals for poor contact.
- If the wiring and terminals are sound, test the PCV regulator valve and control-module circuit according to the manufacturer's diagnostic procedure.
Common fixes
- Repair chafed control-wire insulation and secure the harness away from ground points.
- Clean or replace corroded connector terminals and restore damaged seals.
- Reseat or repair a pushed-back connector pin.
- Replace a faulty PCV regulator valve if circuit tests identify it as the cause.
Can I keep driving?
If the engine runs normally and no other warning appears, a short trip to arrange diagnosis is usually reasonable. Avoid prolonged driving if crankcase ventilation is impaired, since excess crankcase pressure or emissions problems can worsen.
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.