F08 is issue linked heater (open circuit) but remember the failure registers in ACU hast to be erased (otherwise the issue will repeat at end of cycle even Heater will replaced for good one). You need some eeprom programmer, basic EEprom programmer enough, but remember, you need erase power fail area only! Power fail area depends on type ACU example WAVE, WAVE 2, or WAVE B. Wave 2 and B first - 12 bytes (16 bit) and Wave T - first 6 bytes (16bit)
start from zero address.
WinHex в руки и вперёд!
