What it means
A general electrical fault on barometric pressure sensor C — open, shorted, or out of plausibility. The sensor measures atmospheric pressure for altitude compensation; sensor C is a redundant or secondary unit.
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 is a secondary pressure input used by the control module to estimate atmospheric pressure for engine load and altitude compensation. This circuit code sets when the module detects an electrical fault or an implausible signal from sensor C, such as an open, short, or failed sensor.
Common causes
Most likely first.
- Barometric pressure sensor C failed
- Open, shorted, or damaged sensor wiring
- Loose or corroded connector
- Control-module fault
Symptoms
- Check-engine light may illuminate
- Possible rough running or reduced power
- Possible poor starting or hesitation
How to diagnose it
- Read freeze-frame data and compare sensor C's reported pressure with other barometric or manifold pressure readings and local atmospheric conditions.
- Locate the sensor C connector using vehicle service information and inspect its pins, seal, and nearby harness for corrosion, looseness, or damage.
- Check the sensor C wiring for opens or shorts using the vehicle wiring diagram, including power, ground, and signal paths as applicable.
- Test the sensor output and supply circuit against the manufacturer's specifications while checking for intermittent changes when the harness is moved.
- Replace sensor C only if its wiring and connector pass checks but its output remains implausible; investigate a module fault only after circuit tests.
Common fixes
- Reconnect and secure the barometric pressure sensor C connector.
- Clean or repair corroded connector terminals and restore a sound seal.
- Repair an open, shorted, or damaged sensor C harness wire.
- Replace sensor C if its output fails the manufacturer's checks with a sound circuit.
Can I keep driving?
If the vehicle starts and drives normally with a steady warning light, a short trip is generally possible, though altitude compensation and drivability may be affected. Stop if it stalls, loses significant power, or becomes difficult to control in traffic.
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.