Testing glow plugs, connectors, and control unit, DPF

[simt]

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

[simt]

A quick update to my own post:

I've concluded that the controller unit is definitely faulty and in need of replacing.
I used a multi-meter and measured the resistance from the pins on the connection for the controller unit to each glow plug connector. To my relief they all measured fine.
-After that I lay the problem firmly at the feet of the controller.

Also Ista error codes were showing me that the only good glow plug was cyl.4. If you look at those figures I put down, that makes sense. It's the only one good on both counts.

-Simeon

[ard]

1. Glow plug controller failure is very common. Basic recommendation is 'always replace when replacing GPs'

2. "New" DPF?????? Most just clean it out. Why replace?????