What it means
Cylinder 8 pressure sensor reads in range but plausibility check fails. 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 8 pressure sensor measures combustion pressure so the control module can check that cylinder's combustion. This code sets when the signal remains within an electrical range but does not behave plausibly, such as when the sensor has drifted or is mounted loosely.
Common causes
Most likely first.
- Sensor drift
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Symptoms
- Check-engine light
- Rough or uneven engine running
- Misfire or hesitation
- Reduced engine power
How to diagnose it
- Record freeze-frame data and compare cylinder 8 live pressure readings with the other cylinders under the same conditions.
- Inspect the cylinder 8 sensor mounting and connector for looseness, damaged terminals, corrosion, or moisture.
- Watch the live pressure signal while gently moving the cylinder 8 harness to check for unstable readings.
- Check sensor wiring, supply, and ground against the manufacturer's specification to rule out circuit causes.
- If the circuit is sound, assess the sensor output and mounting condition using the manufacturer's diagnostic information.
Common fixes
- Secure a loose cylinder 8 pressure sensor mounting as specified by the manufacturer.
- Repair damaged or corroded connector terminals and wiring.
- Replace a cylinder 8 sensor that has drifted outside its calibrated behavior.
- Correct a confirmed signal processing issue using the manufacturer's procedure.
Can I keep driving?
Limit driving if the engine runs unevenly or loses power, and arrange diagnosis soon. Continued use with implausible cylinder 8 feedback can affect combustion 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.