[duramax0323]

Ok, I have a 2010 chevy buswith a6.6 duramx diesel. The problem happens out of nowhere. If you shut the bus off and leave come back to start it it wont crank at all. No codes are stored starter is new and everything checks out! Any ideas?? It starts after a while again then it happens again

 

[jc1843]

Of course with any start problem-- check the batteries-- They are wired in parrallel so you need to isolate one to test them.

Be sure all the connections are tight and clean.

 

[duramax0323]

Batteries are good! It starts fine when it does start .

 

[jc1843]

I vagely remember there was a problem with the LMM not starting-- and GM had a re-flash for the system-- I searched for a TSB, and could not find anything. Might check with a dealer.

 

[duramax0323]

Hmmm thanks for th input ill try the dealer. This is driving me nuts!!

 

[duramax0323]

We have three of these durmax in the fleet and this one keeps acting up. The other 40one are 6.0 foes diesel and well we all know they suck!

 

[duramax0323]

So I pulled a code. U0168 LOST comm.with vehicle security module. Any ideas?

 

[jc1843]

I think that is the code-- and what I was trying to remember-! I will check over at another place--

Here is a contact -- direct to GM Customer service-- they might be able to help.

http://www.duramaxforum.com/forum/members/45436-gmcustomerservice.html

 

[duramax0323]

If anyone else can chime in it would greatly help!

 

[Johnasara]

Were are you at?
If it is losing communication with the Vehicle security module then it could be the IGN switch, or just something throwing the program loopy. Check all the fuses with an ohm meter or test light when it does it again. You could be losing connectivity when it is warm. Does the bus have an alarm on it or possibly a saftey switch that will disable it?

 

[duramax0323]

No saftety switch on the bus! IM in Elizabeth NJ! Ive checked every fuse multiple times. It could go weeks fine then all of a sudden it starts doing it! Just Stumped

Were are you at?
If it is losing communication with the Vehicle security module then it could be the IGN switch, or just something throwing the program loopy. Check all the fuses with an ohm meter or test light when it does it again. You could be losing connectivity when it is warm. Does the bus have an alarm on it or possibly a saftey switch that will disable it?

 

[Johnasara]

Is there any common factors with the weather or anything? It sounds like you may just have a loose connection. I have no Idea where the security module on a bus Is. I would assume it would be in the relay center. I know the Duramax trucks security is part of the ECM programming.

 

[duramax0323]

Is there any common factors with the weather or anything? It sounds like you may just have a loose connection. I have no Idea where the security module on a bus Is. I would assume it would be in the relay center. I know the Duramax trucks security is part of the ECM programming.

Not really on the weather. Ive checked all grounds and everything. Ill look into the security module to see where its located. Thanks for some input!

 

[duramax0323]

Still having the same issue!! Seems to happen more in the warmer weather!!

 

[jc1843]

Did you contact the dealer to have the security system re-flashed-? There was a TSB on it-- never did find it.

Did you have the batteries tested-?

 

[duramax0323]

Did you contact the dealer to have the security system re-flashed-? There was a TSB on it-- never did find it.

Did you have the batteries tested-?

No I didn't take it tO the dealer!! I've been trying to find the tsb but cant find it!! Batteries are good!

 

[jc1843]

Here is some info--Condition Sorry-- it was NOT for the 2010.
All 2007 and certain 2008 Chevrolet Silverado, Express; GMC Sierra and Savana vehicles, equipped with a 6.6L Duramax Diesel V8 (RPO LMM - VIN 6) engine, were produced with an ECM programming error that can result in incorrect data being written to the EEPROM used by the vehicle theft deterrent system, causing the engine not to crank or start.

Correction
Dealers are to reprogram the ECM with revised software that corrects the programming error.
__________________

Subject:08142A -- ECM EEPROM - Reprogram ECMModels:All 2007 and Certain 2008 Chevrolet Silverado, Express All 2007 and Certain 2008 GMC Sierra, Savana Equipped with 6.6L Duramax V8 Diesel (RPO LMM - VIN 6) Engine
THIS BULLETIN IS BEING REVISED TO ADD MORE 2008 MODEL YEAR VEHICLES. PLEASE DISCARD CUSTOMER SATISFACTION BULLETIN NUMBER 08142, DATED MAY 2008.

 

[jc1843]

When the batteries were tested-- did they isolate them, by removing one cable-? If not, the test is not valid.

I am still thinking batteries, or loose cable.

 

[duramax0323]

Yes one battery at a time!

 

[duramax0323]

Yes one battery at a time! All cables disconnected