fun with computerized vehicles

[JayMaechtlen]

More tales from my Sister the truck driver.

Not just a driver, she and her hubby are owner-operators. That is, they each have a late model Freightliner and put some serious miles on them.

The unit in question is still under warranty, with only 2-3 hundred thousand miles on it.
It seems that sometimes, it will refuse to start. That is, it will not even try to engage the starter.
When it does this, other amusing symptoms are observed, such as the radio volume and other settings reverting to default. After multiple attempts, the vehicle will eventually start.

Of course, it will usually refuse to manifest symptoms when in the shop.
Of course, its on-board diagnostics have no record of the occurrence, nor any clues of what might have occurred.

She got lucky - she had it in the shop for a different mysterious ailment, and it manifested the no-start symptom instead.
Of course, it went away before they could get diagnostics connected up. But, at least the mechanic saw it happen!

It seems that Freightliner has seperate/different diagnostic systems for the engine, the transmission, and possibly some other systems. Those diagnostic systems run on Windows, and may or may not run at any particular time.


This really sounds like several kinds of "bad old days"!
(Did Freightliner sub the software out to Toyota?)
(El Truck es Hecho in Mexico)
cheers
Jay

Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[MikeHalloran]

First thing to check: Corroded/ missing/ fractured ground straps. All of them.


Mike Halloran
Pembroke Pines, FL, USA

 

[ZephTheChef]

I agree. Sounds exactly like a battery cable going bad. I see this on cars in the shop all the time. Intermittent no-starts, often times won't even jump-start unless you go straight to the starter with the cable. Almost always a corroded or loose battery cable or ground strap somewhere.

 

[JayMaechtlen]

Thanks for the suggestions - I forwarded them along to her, to offer to the dealer techs.
It will be interesting to see what they come up with, or what they're willing to admit...

Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[Comcokid]

Since it is a newer truck, don't overlook a common manufacturing defect: The ground lead, or grounding straps bolted directly to a well-painted block (or well painted frame).

 

[MikeHalloran]

It seems that Freightliner has seperate/different diagnostic systems for the engine, the transmission, and possibly some other systems. Those diagnostic systems run on Windows, and may or may not run at any particular time.

Many/most trucks are sold 'a la carte', i.e., you can order pretty much any combination of engine/transmission/axles/suspension/brakes/etc. that you are prepared to pay for, including combinations that don't work well together. ... and that's just the mechanical stuff. The electronics situation is worse.



Mike Halloran
Pembroke Pines, FL, USA

 

[JayMaechtlen]

Update-
The truck would shut off by itself.
If moving fast enough, it would typically stutter and come back to life.
If not, she would have to try to coast to the side, and eventually it would restart and run fine.
The diagnostic systems never showed any faults.

One day, it did while she was in a parking lot, and as she opened the door to get out, she saw a light on the power control unit under the cab by the running board (battery management, etc) blinking furiously.

She called the dealership (or tech support?) and they said "AHA!"
It seems there's a master switch and that was the issue.

$250 plus installation, and it is running fine.

yay!

Jay Maechtlen

http://www.laserpubs.com/techcomm