P03CB: Cylinder 6 Pressure Sensor Circuit Intermittent/Erratic

What it means

Cylinder 6 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 6 pressure sensor tracks combustion pressure from one firing cycle to the next. This code sets when its signal jumps or drops out unpredictably, often because vibration or harness movement interrupts the sensor connection.

Common causes

Most likely first.

1. Intermittent connector
2. Connector with intermittent contact under vibration
3. Harness routed against vibrating component

Symptoms

• Check-engine light

How to diagnose it

1. Record freeze-frame data and watch the cylinder 6 pressure-sensor signal on a scan tool to confirm whether it drops out while the fault is present.
2. Inspect the sensor connector for loose fit, moisture, corrosion, or terminals that have lost contact.
3. Check the cylinder 6 harness routing for rubbing or contact with a vibrating or moving part.
4. While monitoring live data, gently move the connector and harness to look for a repeatable signal interruption.
5. If movement does not reveal the fault, check wiring continuity and terminal fit, then test the sensor to the manufacturer's specification.

Common fixes

• Secure the harness away from rubbing or vibrating parts.
• Restore connector terminal tension or repair an intermittent connection.
• Repair damaged wiring and reseal a connector exposed to moisture.
• Replace the cylinder 6 pressure sensor if its signal remains erratic with sound wiring.

Can I keep driving?

If the only symptom is the check-engine light, drive gently and arrange diagnosis soon. Avoid heavy loads; stop if rough running or power loss develops.