What it means
Cylinder 3 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 3 pressure sensor reports combustion pressure to the engine control module. This code sets when its signal jumps, drops out, or otherwise changes erratically, often as a loose or damaged connection moves with vibration.
Common causes
Most likely first.
- Intermittent connector
- Connector with intermittent contact under vibration
- Harness routed against vibrating component
Symptoms
- Check engine light on
- Intermittent rough running or misfire
- Intermittent loss of engine power
- Possible stalling or hard starting
How to diagnose it
- Save freeze-frame data and watch the live cylinder 3 pressure signal for dropouts while the engine runs.
- Inspect the cylinder 3 sensor connector for loose retention, corrosion, moisture, or terminals that have backed out.
- Check whether the harness is rubbing against or vibrating against nearby components, and look for damaged insulation.
- While monitoring the signal, gently move the cylinder 3 connector and harness to see whether the reading changes.
- Check continuity and the sensor supply and ground circuits while flexing the harness, then test the sensor if the wiring remains stable.
Common fixes
- Secure the connector and repair loose or corroded terminals.
- Repair damaged wiring and reroute or secure the harness away from vibration and abrasion.
- Restore the sensor ground or supply connection if testing finds an intermittent fault.
- Replace the cylinder 3 pressure sensor if its output remains erratic with sound wiring.
Can I keep driving?
Avoid long trips or heavy acceleration while the signal is dropping out, especially if the engine misfires or loses power. If it stalls or runs very roughly, stop driving until the fault is checked.
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.