Had this car in January with rough running and cooling fans running randomly, ecu was outputting random voltages to temp sensor, ecu was replaced with genuine Vauxhall recon unit.

Three months later its back showing P0200 injector voltage high.

It appears to set the code when cranking, if I clear it after the engine starts it does not reappear until the next start, it runs perfectly.

Scoped injector for volts v amps perfect pattern,sorry forgot to save it, checked ecu earths and feeds found ok.

However when the car is completely turned off there is still 0.498v on the injector and coil feed wires which disappears when ecu is unplugged.

Can the driver allow a back feed and does this mean a faulty ecu ? is that half a volt causing it to flag the mil on ?

I checked a known good car belonging to a neighbour and 0v present on these wires.

Any thoughts appreciated.