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View Full Version : DTC 46 and a lesson learned well



Robyn
07-02-2007, 19:32
many of you may have read my post on the code 46

This code refers to "MIL circuit fault"
This can be a burned out bulb or bad connection in the dash or even more derious issues.
My dually was popping these every so often and yesterday It did it in the afternoon and with the code came the dreaded "LIMP MODE"

Geeeeeeez no power MA now what, cleared the code with Ign off then back on.

Ripped the dash apart and cleaned all the connections and now the volt meter works right and the code has not come back "YET"
I read the whole section in the GM manual I have on this stuff and it does not mention anything about Limp mode for Mil fault code.

The two GM truck shops here close had never even heard of a DTC 46 let alone diagnosed one.
I called Heath diesel and talked to Todd, he not only knew what I was talking about but also confirmed that this DTC will activate the limp mode.

Issue being if the bulb burns out or the test circuit is otherwise compromised the driver would never know that a problem existed.
The limp mode gets your attention real quick. :eek:

Just a very interesting day at the office today for sure, but I learned something, so all is well.

Hope this is of use to someone

Robyn

twaddle
07-03-2007, 07:31
Hi Robyn,
Ain't the newer trucks fun?

Just shows ya "You learn something new everyday".

Thanks for letting us know, keep going like this you'll be writing the next 6.5 problem solving book.

Good luck with the new truck and I hope you get the gremlins fixed for long enough to enjoy it.
It reminds me of when I shipped the Suburban in from Texas. After I got it on the road and paperwork sorted out it ran like a champ for 7 or so weeks then stalled on me, fired right up then ran for another 7 weeks or so. The fact the fault was so intermittent was real fun.
I have had the truck over 5 years and recently changed the PCM which seems to have cured any stalling. (Touch wood)

Regards

Jim
Biggar, Scotland
Soon to be Alberta, Canada