What it means
Cylinder 8 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 8 pressure sensor reports combustion pressure to the control module. This code sets when its signal falls below the plausible range, commonly because the signal is shorted to ground or has excessive resistance at a connector.
Common causes
Most likely first.
- Short to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light on
- Possible engine misfire or rough running
- Reduced engine power
- Poor fuel economy
How to diagnose it
- Record freeze-frame data and check whether cylinder 8 pressure data is persistently low or drops under particular conditions.
- Inspect the cylinder 8 sensor connector and harness for chafed insulation, moisture, corrosion, or loose terminals.
- With live data displayed, gently move the cylinder 8 harness to see whether the reading changes or the fault returns.
- Test the cylinder 8 signal wire for a short to ground and check for opens or poor terminal contact using the manufacturer's wiring information.
- Verify sensor supply and ground, then test the sensor against the manufacturer's specification if the circuit is sound.
Common fixes
- Repair chafed cylinder 8 wiring that is touching ground.
- Clean or replace corroded or loose terminals at the cylinder 8 sensor connector.
- Repair an open or high-resistance connection in the sensor circuit.
- Replace the cylinder 8 pressure sensor if it still reads low with a verified circuit.
Can I keep driving?
If the engine runs roughly, loses power, or uses more fuel, avoid long trips and heavy loads until the fault is diagnosed. Stop driving if misfiring becomes severe, since continued operation can worsen engine and emissions problems.
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.