P0685

What it means

The control circuit of the main ECM/PCM power relay is open - the ECU can lose power on shutdown sequence or fail to wake up at next start.

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

• Open in relay control or harness

  high

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

• Pin pushed back out of connector body

  low

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

• Cracked solder joint inside the module or sensor

  low

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

Related help

• Full P0685 diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?