My 760 turbo broke down on the road, eventually diagnosed as no fuel and faulty fuel gauge sender unit.

However the breakdown lorry and the garage both initially diagnosed that there were no injector pulses.
They did this intially with an LED attached, with the injectors disconnected.

So it took a long time to find there was no fuel, and a replacement ECU was temporarily fitted as part of the diagnosis.

This is the B230ET with LH 2.4 system and has the separate "power stage" unit for the ECU and the "radio supression" relay.

The garage advised that the positive power was there OK at the injectors, but the negative ground pulses were not present. The wiring diagram in Haynes shows the negative pulses go from the ECU through the "power stage" and there appear to be individual circuits for each injector.


Does anyone know why the LED did not show injector pulses?

For example does the ECU or "power stage" know the injector is not connected [as the electrical resistance is wrong] and so not pulse the ground?

I would like to know:-

a) for any future problem diagnosis.
b) to negotiate my garage bill for this breakdown.

Thank you


GrahamG