Glow plug bad --> change control unit?
 

Hi guys,

My 35d is at the dealer, the CEL was on and I suspected the DEF was at fault again. I filled the active tank but that didn't help. They diagnosed the metering valve is faulty. It is being replaced under parts warranty.

They checked the fault codes and claim it has a bad glow plug #6 as well. Not impossible at this mileage. But SA caims he needs to change the glow plug control unit and the total is $1200. A glow plug is 40 bucks and the unit is 150-200 or so, so I struggle to understand why the total is 1200? Does it really take them a whole day to change one GP and the unit?

Of course I also "need new tires", I always do it seems. I have yet to come back from a visit to the dealer and not need brakes or tires....

HERE IS MY QUESTION, did anyone DIY their glow plugs? Did you change the preheat control unit?

Is this thread about changing glow plugs or faulty metering valve?

Neither, two questions really.

1. Why would he claim almost a full day of labour to change one glow plug and the GPC?

2. Why does he think that given a faulty glow plug, the GPC also needs to be changed?

Finally, it would be interesting to see if anyone has tried to change the GPs. I found a UK based site where posters seem to think it is doable but tricky.

Why? becuase you'll pay it.

Id have them fix the free item, GET THE CODES, and see how it runs. Who knows if the glow plug code is present or active...could be an old spurious code.

Then get something to pull your own codes.

I just dont trust BMW dealers with these newer diesels...too much "replace the part based on what the design engineer decided should be done based on a code".

Did they run a testplan to chase down the glowplug code? What precisely was the code and what testplan did they do?

For $1200 you deserve some answers first, cause your not gonna get a reacharound

I had a glow plug fail under warranty and it was caused by the control unit voltage being too high. Both were changed and it has been fine since.
Chuck

Spot on! I told him exactly that. They'll fix the DEF metering and then we'll see. I was reading up on the glow plug issue and it doesn't seem logical to me to change the GPC if there is only one that shows a code.

And no, I won't hand over 1200 dollar for that job, that is outrageous. Anyway, I did my own AT rebuild and the V-pan gasket on the e53. I have a feeling I can manage the GP change as well. (It does seem there is some prep and forethought needed to avoid shearing them.)

One rear airbag on occasion sags, I bet they'll spot that one in the morning.....

I am just reading uphow to get going with INPA, etc.

Chuck, thanks. Good to know that.

Just for clarification...

You had a prior metering valve failure? They replaced that under warranty, now you are out of warranty but the part replaced had a 2/24 warranty?

Wondering why the GP isnt covered.

Correct, last year the car was already out of warranty but they replaced a bunch of stuff for free related to the DEF including the metering valve. That was already under 2/24 repair warranty. So now the MV failed again and they replaced again.

The GP failed and seems in need of replacement which is fine. Iam just unsure why they deemed the GPCU as the cause of the failure and why it takes a $1000 in labor to change these two parts. Seems a bit much to me.

I was busy today and picked up the car late. The SA had left. However I got his card and intend to send him an email to find out about this.

If nothing else I will replace the GP (a $40 part) and see how it does. If it fails again the GPCU is faulty. If it works fine the GP is the only problem.

^^ Ask him if there is an SIB related to this issue....(it may have instruction on the cause as well as what actions they recommend)..also ask how they diagnosed the bad control unit...was it a test plan they ran that IDd the bad unit, or an SIB that says 'replace this' or just the mechanic's intuition.