P03C9

What it means

Cylinder 6 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.

Is it safe to drive?

This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly.

Most likely causes

• Short to ground

  high

  One of the most commonly reported causes for this code — check this first.

• Connector pins corroded - high contact resistance

  low

  Less common, but worth ruling out after the more likely causes.

• Harness chafing through insulation

  low

  Less common, but worth ruling out after the more likely causes.

Related help

• Full P03C9 diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?