P0991

What it means

The transmission fluid pressure sensor/switch E reports a circuit intermittent fault. Hydraulic pressure feedback for shift control is unreliable on this channel.

Is it safe to drive?

This code can put the vehicle into limp or reduced-power mode. Avoid extended driving and have the vehicle diagnosed promptly.

Most likely causes

• Connector not seated

  high

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

• Harness chafing intermittently

  medium

  A plausible cause — test and verify before replacing parts.

• Connector with intermittent contact under vibration

  low

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

Related help

• Full P0991 diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?