P24EF

What it means

The wake-up line that brings a sleeping ECU back from low-power mode is open. Many networks use a dedicated hardware wake-up wire (door-latch trigger, terminal 15, CAN wake-up) so modules can stay asleep with the ignition off. Without it, the module either fails to wake up at start-up or stays awake and drains the battery.

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

• Broken wake-up wire or unplugged connector

  high

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

• Failed wake-up input stage in the module

  medium

  A plausible cause — test and verify before replacing parts.

• Pin pushed back out of connector body

  low

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

Related help

• Full P24EF diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?