P235B

What it means

The closed-loop combustion controller reports that combustion performance on cylinder 10 is below the calibrated quality metric. Computed from the cylinder pressure trace — IMEP (indicated mean effective pressure), CA50 (50% mass burnt angle) or peak pressure deviates from the model.

Is it safe to drive?

The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.

Most likely causes

• Mean effective pressure outside model

  high

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

• Gateway module routing CAN messages incorrectly

  low

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

• CAN terminating resistor (120 Ω) drifted out of spec

  low

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

Related help

• Full P235B diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?