P235F: Cylinder 11 Pressure Sensor Circuit High

What it means

Cylinder 11 pressure sensor above upper plausibility — open signal or short to B+. 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 11 pressure sensor signals combustion pressure to the control module, which checks that the circuit signal stays within an expected range. This code sets when the signal is too high, commonly because the signal wire is open or shorted to a supply voltage.

Common causes

Most likely first.

1. Signal line shorted to supply
2. Connector pins corroded - high contact resistance
3. Supply wire pinched against B+ source

Symptoms

• Check-engine light
• Rough running or misfire
• Reduced engine power
• Poor acceleration

How to diagnose it

1. Save freeze-frame data and inspect cylinder 11 pressure-sensor data for a high reading or a reading that stays fixed.
2. Check the cylinder 11 sensor connector and harness for open wires, damaged insulation, corrosion, or pins pushed out of place.
3. Watch the live signal while gently moving the harness to see whether the high reading changes.
4. Using the manufacturer's wiring information, test the signal wire for an open circuit or short to a supply.
5. Check sensor supply, ground, and signal behavior against the manufacturer's specification to identify whether the sensor or wiring is at fault.

Common fixes

• Repair an open or damaged cylinder 11 sensor signal wire.
• Repair insulation where the signal wire contacts a supply source.
• Correct loose, corroded, or displaced connector pins.
• Replace the cylinder 11 pressure sensor if it fails testing.

Can I keep driving?

Keep driving to a minimum if the engine is rough or has reduced power, and avoid heavy loads. Stop if the misfire worsens, since poor combustion can increase emissions and engine stress.