U300A

What it means

The control module detects an inconsistent or implausible ignition switch state — multiple positions reported simultaneously, or the position contradicts other inputs.

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

• Ignition switch contacts worn

  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 U300A diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?