P0335

[CarolinaHD]

This is from the gm service manual and it may or may not help. Have you physically checked the reluctor wheel? I remember reading somewhere that just a small nick on a tooth on the wheel prevented the truck from starting.

 

[03Duramax86]

Yeah we checked the reluctor wheel and it looked good and was not loose at all. I will re check tonight when I get home. I'll look over what you just posted and see what I can find. Thank you.

 

[CarolinaHD]

This post is what I was referring to.

http://www.duramaxdiesels.com/forum/showpost.php?p=936298&postcount=78

 

[03Duramax86]

Thank you, I will take a look when I get of work.

 

[wilsondiesel]

Try relearning the vats or get the vats disabled in the tune. I had a very similar scenario on a '02 LB7. Just an idea.

 

[onebaddmaxxx]

vats will let it fire but shut right back off.

 

[03Duramax86]

Is the vats something I would have to have Idaho Rob mess with? Also I am starting to thing my ecm is bad.

 

[onebaddmaxxx]

Vats is not your issue

 

[03Duramax86]

Do you have any idea what could be my problem? I've already put in 2 crank sensors.

 

[DAVe3283]

If a Tech 2 doesn't show cranking RPM, there are only a couple problems that can cause that.

1. Bad ECM (this is not common, but if a friend has an ECU you can swap with to test, why not?)
2. Damaged/loose crank or cam reluctor (or a broken crankshaft)
3. Bad sensor or wiring harness problems

I attached the service procedures for the 2 DTCs you have set. I'd run through those and see if they get the issue fixed.

 

[03Duramax86]

Thank you!!! I will go through all of this tonight and see what I come up with. Unfortunately I don't have anyone around that has an ECM I could try out.

 

[03Duramax86]

Looks like I'm going to need a new ecm!! Anyone on here have one for a lb7?

 

[03Duramax86]

Update: ended up getting a good ficm and truck fired right up.

 

[Harbin_22]

Glad you got it resolved and letting everyone know what it was.

 

[mdemaree227]

I know this is an old issue but I’m have the exact same issues and have done very similar troubleshooting. How did you determine the ficm was bad?

 

[2004LB7]

Most of the time it pops the EDU fuse

 

[mdemaree227]

Ok awesome thank you for the reply I’ll check that tomorrow. Then gonna send it off to get checked

 

[2004LB7]

If you send it out, Don't throw it out if they say it's not reparable

 

[mdemaree227]

Ok I started with my Ecm and they said it was none repairable and sent back the old one. Truck wouldn’t crank at all till I got a refurbished ecm and it will crank now but having almost the exact same issues 03duramax86 was having with his truck

 

[mdemaree227]

Edu fuse was good and swapped relay. So I guess back to rechecking wires and connections or I may still send ficm off to get checked since Ecm was bad.
Just to confirm tho on my crank sensor when I tap into the wires with my paneer prob I get 11.8v on blue/white 12v on green and ground on yellow/black. If I un plug the crank sensor I loose 11.8 on blue/white tho