there is one main earth for the ecu
remove the gearbox earth clean and refit
remove the chassis earth clean and refit (cables under the battery bolted to the chassis leg)
check the earth cable from the battery to gearbox to chassis leg is good not burned or broken
there is one main + supply point for the ECU
the tap off is on the Alternator there is 3 wires
1 small wire is the exciter
1large + 1 small is Battery and ecu feed
check the main battery positive as it runs...
battery>starter>Alternator at Alternator the smaller wire connected is the ecu feed this can burn off
also check the big fuses in the engine bay box
40Amp + 60amp ones
remove the gearbox earth clean and refit
remove the chassis earth clean and refit (cables under the battery bolted to the chassis leg)
check the earth cable from the battery to gearbox to chassis leg is good not burned or broken
there is one main + supply point for the ECU
the tap off is on the Alternator there is 3 wires
1 small wire is the exciter
1large + 1 small is Battery and ecu feed
check the main battery positive as it runs...
battery>starter>Alternator at Alternator the smaller wire connected is the ecu feed this can burn off
also check the big fuses in the engine bay box
40Amp + 60amp ones
https://www.check-mot.service.gov.uk/
GTI6 Info
Don’t drive faster than your guardian angel can fly.