What it means
Cylinder 5 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 5 pressure sensor measures combustion pressure, and the engine control module monitors its signal circuit to assess that cylinder. This code sets when the signal falls below the module's plausible range, commonly because the signal is shorted to ground or has a poor, high-resistance connection.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check-engine light
How to diagnose it
- Review freeze-frame data and live cylinder 5 pressure readings to confirm the low signal and note when it occurs.
- With the ignition off, inspect the cylinder 5 sensor connector for corrosion, moisture, loose terminals, damaged seals, or pins pushed back.
- Trace the cylinder 5 sensor harness for chafing or insulation rubbed through where it could contact ground or an engine surface.
- Monitor the cylinder 5 signal while gently moving the harness and connector to see whether the low reading changes.
- If the visual checks do not locate the fault, test the signal wire for a short to ground and check circuit continuity using the vehicle wiring diagram.
- If wiring and connections pass, test the sensor and its supply and ground against the manufacturer's specification before considering a module fault.
Common fixes
- Reconnect and secure a loose cylinder 5 pressure sensor connector.
- Clean or repair corroded terminals and replace damaged connector seals.
- Repair chafed cylinder 5 signal wiring and secure it away from grounded surfaces.
- Replace the cylinder 5 pressure sensor if it fails testing with the circuit verified.
- Repair a confirmed sensor supply, ground, or control-module fault.
Can I keep driving?
A check-engine light may be the only symptom, but the engine control module may not have usable pressure data for cylinder 5. Avoid heavy loads if the engine runs poorly, and address the fault soon because combustion control and emissions can be affected.
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.