P077D

What it means

Output shaft speed sensor signal voltage above the upper limit — short to reference voltage or open signal return.

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

• Signal wire shorted to reference voltage

  high

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

• Connector pins corroded - high contact resistance

  low

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

• Supply wire pinched against B+ source

  low

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

Related help

• Full P077D diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?