What it means
Cylinder 3 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 3 pressure sensor measures combustion pressure so the engine control module can assess that cylinder’s combustion. This code sets when the signal is higher than the module considers plausible, which can happen if the signal circuit is open or pulled toward 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 on
- Rough running or misfire
- Reduced engine power
- Hard starting
How to diagnose it
- Record freeze-frame data and check live cylinder 3 pressure readings for an implausibly high or fixed value.
- Inspect the cylinder 3 sensor connector for moisture, corrosion, loose pins, or a pin pushed back from its position.
- Trace the cylinder 3 sensor harness for chafing or a signal wire touching a battery-positive feed.
- With the wiring diagram, check the sensor supply, ground, and signal circuits for opens or unwanted voltage against the manufacturer's specification.
- If wiring and connections pass, compare the cylinder 3 sensor signal with the other cylinders and test the sensor as specified by the manufacturer.
Common fixes
- Clean and securely reconnect a contaminated or loose cylinder 3 sensor connector.
- Repair a chafed signal wire or a wire shorted to a battery-positive feed.
- Repair an open circuit or replace a terminal with poor contact.
- Replace the cylinder 3 pressure sensor if its signal fails the manufacturer's test.
Can I keep driving?
If the engine runs smoothly, drive only as needed and avoid hard acceleration until diagnosed. Rough running or reduced power can worsen, and a misfire may damage the catalytic converter.
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.