P2D40

What it means

The hybrid battery cooling system C does not maintain target temperatures under load. Coolant flow, radiator fouling, or pump output reduced on this branch.

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

• Radiator fins fouled - reduced heat rejection

  high

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

• Pump output degraded with age

  medium

  A plausible cause — test and verify before replacing parts.

• Pack cell imbalance approaching service threshold

  low

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

Related help

• Full P2D40 diagnosis, causes & costs
• How to read check engine light codes
• Is it safe to drive with the light on?