What it means
Cylinder 3 pressure sensor below lower plausibility — short to ground. 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 sends a signal to the engine control module so it can monitor combustion pressure in that cylinder. This code sets when the signal falls below the plausible range, commonly because it is shorted to ground or the connector has excessive resistance.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
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 data for a reading that stays low or drops out.
- Inspect the cylinder 3 sensor connector for corrosion, moisture, loose fit, or pushed-back pins that could raise contact resistance.
- Trace the cylinder 3 signal wire for worn insulation or chafing where it could contact ground.
- With the code active, gently move the harness while watching live data to see whether the low reading changes.
- Test the cylinder 3 signal, supply, and ground circuits against the manufacturer's specification to confirm a short to ground or high-resistance connection.
Common fixes
- Repair chafed cylinder 3 wiring that is contacting ground.
- Clean and dry the connector and repair corroded or loose terminals.
- Repair an open, short, or high-resistance connection in the cylinder 3 sensor circuit.
- Replace the cylinder 3 pressure sensor if the circuit checks out but its signal remains too low.
Can I keep driving?
Drive gently and avoid heavy loads if the engine is rough, misfiring, or down on power; the module may not be able to monitor cylinder 3 combustion accurately. Stop if the engine runs severely rough or stalls, and arrange diagnosis soon.
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.