What it means
Cylinder 8 pressure sensor signal jumps or drops out intermittently — connector or wiring issue. 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 signal lets the ECM track combustion pressure in that cylinder. This code sets when the signal drops out or jumps unpredictably rather than remaining stable, often as vibration moves a poor connector or damaged harness.
Common causes
Most likely first.
- Intermittent connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check engine light on
- Intermittent engine misfire or rough running
- Hesitation or loss of power
- Uneven engine performance
How to diagnose it
- Save freeze-frame data and monitor cylinder 8 pressure sensor live data to identify when the signal becomes erratic.
- Inspect the cylinder 8 sensor connector for corrosion, water ingress, loose fit, or terminals that have backed out.
- Examine the harness along its route for chafing or contact with a vibrating component, then gently flex suspect sections while watching the live signal.
- Check continuity and terminal fit in the cylinder 8 sensor signal, supply, and ground circuits while moving the harness.
- If the wiring remains stable, test the cylinder 8 pressure sensor and its ECM input using the manufacturer's procedure.
Common fixes
- Secure the cylinder 8 sensor connector and clean or replace terminals with intermittent contact.
- Repair damaged insulation and reroute the harness away from vibrating or rubbing parts.
- Replace a connector seal that is allowing moisture into the cylinder 8 sensor connection.
- Replace the cylinder 8 pressure sensor if its output remains erratic with sound wiring.
Can I keep driving?
A brief drive may be possible if the engine is running normally, but avoid hard acceleration and arrange diagnosis soon. If misfiring, hesitation, or power loss appears, stop driving because the intermittent signal may disrupt combustion control.
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.