HEX: 88 - Fuel pump interruption

Fault Details:

The fuel pump is interrupted or shorted to supply voltage UB.

Recommended Solution:

Electrical check of the fuel system. Check if the fuel pump cable is not damaged, rubbed off, and the plug is pushed in all the way. Check if the pins are inserted correctly, check for oxidation, and visual damage. 

Note, different models and controllers might have different fault code meanings. If you're not sure, you can contact Heatso directly.