P225D

What it means

NOx Sensor Performance - Signal Biased/Stuck Low (Bank 1 Sensor 1): the component is electrically intact but its response does not match the command.

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

• Sensor aged or condensate damaged

  high

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

• Sensor element aged beyond calibration window

  low

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

• Sensor element contaminated by oil, soot or coolant

  low

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

Related help

• Full P225D diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?