What it means
Cylinder 5 pressure sensor 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
The cylinder 5 pressure sensor measures combustion pressure in that cylinder so the engine controller can assess each firing event. This code sets when the signal is implausibly high, such as when the signal wire 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
How to diagnose it
- Use a scan tool to confirm P03C0 and record freeze-frame conditions before clearing it.
- Check the cylinder 5 pressure sensor connector for moisture, corrosion, pushed-back pins, or a poor lock.
- Inspect the signal wiring from the cylinder 5 sensor for chafing, pinching, or contact with a power wire.
- With the fault present, monitor the sensor signal while gently moving the harness to see whether the reading changes.
- Test the signal wire for continuity and shorts to battery voltage using the vehicle wiring diagram and manufacturer's procedure.
Common fixes
- Reseat the cylinder 5 pressure sensor connector and secure its harness away from chafing or heat.
- Clean or repair corroded or pushed-back connector terminals.
- Repair an open or pinched signal wire, or insulation damaged where it contacts a power source.
- Replace the cylinder 5 pressure sensor if wiring and connections test correctly but its signal remains implausibly high.
Can I keep driving?
With only the check-engine light and no running problems, a short trip to diagnose it may be possible, but avoid heavy loads. Stop if the engine begins running roughly or loses power, since the controller may not be able to assess cylinder 5 combustion correctly.
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.