F84 Fault — Implausible flow and return temperature sensor values

What does F84 mean?

The flow and return temperature sensors are returning illogical values, possibly due to being inverted or incorrectly installed.

• Flow and return temperature sensors have been inverted
• Flow and return temperature sensors have not been correctly installed

Click steps to track your progress.

1. 1

   Check that the flow and return thermistors are clipped onto the CORRECT pipes.

2. 2

   Ensure the thermistors have good contact onto the pipes.

3. 3

   Check the resistance across both thermistors (requires specialist tools).

4. 4

   Check the continuity down the wiring harness for both sensors (requires specialist tools).