What it means
Barometric sensor C above upper plausibility — open signal or short to B+. 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
Barometric pressure sensor C provides the control module with a pressure reading used to assess atmospheric conditions and engine operation. The module sets P227D when sensor C's signal is above its plausible upper limit, which can happen if the signal circuit is open or shorted to battery voltage.
Common causes
Most likely first.
- Open signal line
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light may illuminate
- Possible reduced power or hesitation
- Usually no obvious symptoms if the reading remains close to normal
How to diagnose it
- Check freeze-frame data and live readings for barometric pressure sensor C to see whether its value is implausibly high or differs from other available pressure readings.
- With the ignition off, inspect sensor C's connector and wiring for corrosion, pushed-back pins, chafing, water entry, or contact with a battery-positive wire.
- Check the sensor C signal, supply, and ground circuits for opens or shorts, following the wiring diagram and manufacturer's specification.
- While monitoring sensor C's live value, gently move the harness and connector to see whether the high reading changes.
- If the wiring and connections test correctly, test sensor C against the manufacturer's specification before considering a control-module fault.
Common fixes
- Reconnect or secure a loose sensor C connector.
- Clean or repair corroded or pushed-back connector terminals.
- Repair an open or chafed sensor C signal wire.
- Separate and repair a signal wire shorted to battery voltage.
- Replace sensor C if it fails testing to the manufacturer's specification.
Can I keep driving?
If the engine runs normally and the reading remains close to plausible, a short, cautious drive may be possible, but avoid hard acceleration if power drops or the engine hesitates. Arrange diagnosis soon because an inaccurate pressure input can affect engine control 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.