Hi all,
I'm trying to figure out if I need a new glow plug control unit.

I've removed the inlet manifold on my X5 35D ( M57TU2) and I've tested the 6 glow plugs. 3 bad, 3 good. Replacing all of them.

However I also measured the voltage in each of the connectors to the glow plugs. I did this simply by unlocking the car a few times so it would start its ~30sec pre-heating routine. In 3 of them I measured a consistent 3.8V. The other 3 were 0V. (btw the 0V connectors don't match the bad glow plugs.)
Does this mean a bad control unit? Or could it be an issue with the wiring? There is a bit of oil on some of the wiring for the connectors.

The whole reason for the glow plug checking is because my DPF died and I'm buying a replacement. The shop told me to make sure my engine was in good running order, or it could lead to premature failure of the new DPF. Glow plug activation was one of the faults listed in ISTA.

Any advice would be welcome.
-Simeon


For those curious here's what I measured:

Cyl .glow plug (ohms) .Connector (V)
1 . 0.3 . 0v
2 Inf 0v
3 28.2 3.8v
4 0.2 3.8v
5 0.3 0v
6 193 3.8v