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Playing With Auto-4wd

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music Senior Enthusiast

music

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Reading a thread here about "how auto-4 works" had me thinking, so I went to the garage to play a bit. I switched the 4wd selector dial to "Auto", dipped under the truck to listen, and then switched to 4hi... and listened. Then 4lo... listen. Back to 4hi... listen. Did this for a minute or so, and learned that there are electronic engagements occurring in both the front diff and the transfer case, all with the engine off. That's well and good, but then I moved it a little too quick back and forth and it stopped responding. A message appears on the DIC to the effect of "service 4wd". Started truck, same. Backed out of garage and found that it was locked in 4hi. Same message. Start. Off. Start. Off. Same... "service 4wd system".

 

Popped the hood and read the fuse panel. On a guess, I picked the "ECC" 30A fuse, and just to double my chances, also pulled the "ECM Batt" 10A fuse. Let it sit for a minute, and put 'em back. Fixed! So, I did something dumb by playing with it, but found a quick fix. Just a FYI post...

nick3941sd Enthusiast

nick3941sd

Posted
Posted

Yeah from what ive seen its somewhat easy to get one of those service 4wd lights on in these things. But it also seems that more than not you can fix it with a reset like you did. Glad nothing broke on ya lol.

GPGuy Senior Enthusiast

GPGuy

Posted
Posted

Thanks for the info. Glad to hear nothing broke on you. I will keep this in mind if I ever happen to see that message. :cheers:

music Senior Enthusiast

music

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Posted

I actually didn't expect that I had broken anything (or even that it could easily). It was engaging/disengaging very smoothly. I did it too quickly (or too many times) and confused the controller, and it stopped responding to the input switch. Once it set the "trouble detected" flag in memory somewhere, it wouldn't forget. The reset did it, but I wish I had only pulled one fuse at a time so I knew which of the two it was. Either the ECM-BATT (#12 10A) or ECC/ASC (#2 30A).

dewfpo Senior Enthusiast

dewfpo

Posted
Posted

It takes a few seconds for the actuators to engage, sometimes the vehicle must be rolling for them to mesh, I'm sure you just confused the ECM. When that happens, the DIC should just say "STOP, playing with the controls, your confusing me!!!!"

 

DEWFPO

Ron_CA Enthusiast

Ron_CA

Posted
Posted

I did a test on mine yesterday in the rain. When leaving a convenience store parking lot and pulling out onto a road, I switched into auto 4wd mode and then hammered the gas, rear tires spun for a mili second then the front engaged and I took off like a bat out of hell. :cheers: I was pretty impressed at how much traction I had.

99silveradoz71 Senior Enthusiast

99silveradoz71

Posted
Posted

I'll give a worse story about auto 4wd. Had the truck out in the first snow of the year a few weeks back. I dialed in the auto, and drove about 1/4 mile afterward. All of the sudden I hear a boom and get the low oil pressure/shutdown immediately lights/messages. I get off onto a side street and pop the hood. The front shaft disconnected right at the front joint. Mind you the truck has 27,700 on it and is an 08. I put 5k on it last year, so it doesn't go out too far. Had it towed to the dealer and thankfully, they discovered the shaft had become disconnected and smacked the oil filter. I had the oil pan gasket replaced in August, and I'm suspecting that when doing the repair, they dropped the front shaft to allow for more room and failed to secure everything properly. Suffice to say, no charge on the repair.

Ape0r Enthusiast

Ape0r

Posted
Posted
boy I'm glad my truck has a lever you move to engage 4wd..

 

+1. Only problem it has ever given me is being a little harder to pull into 4wd when very cold. My girlfriend's bros SUV (a yota, barf) has decided that it doesn't want to go into 4wd. Period. Had to tow it up their snowy driveway with her dad's front wheel drive ford edge w/ snow chains :cheers:. Sad to say, my truck was a little too far (3000 miles) away.

nick3941sd Enthusiast

nick3941sd

Posted
Posted
boy I'm glad my truck has a lever you move to engage 4wd..

 

+2 i would rather have the lever but my truck has the switch.

ColoradoSkiCountry Senior Enthusiast

ColoradoSkiCountry

Posted
Posted

Yesterday was the first day the Denver area saw snow since last April there was enough on the roads that anyone with crappy tires (including the crappy Bridgestone's I have on mine right now that still have 1-2 years left on them) would have problems getting around. Between using Auto and 4-Hi, I very much prefer it in 4-HI setting now over Auto. It seems to take a second or two for Auto to figure out which diff to engage where as in 4-Hi it's already locked in and away I go, no problems.

sabre364 Enthusiast

sabre364

Posted
Posted

You'd think they would sell an option where all 4 wheels are fully driven ala awd fashion but with a 4lo selector switch. That would be the BEST system they could put in a truck IMO. You'd lose less than 1 mpg for the EPA ratings and it is far superior to having to worry about a switch.

BlackZ71Silverado Senior Enthusiast

BlackZ71Silverado

Posted
Posted
Yesterday was the first day the Denver area saw snow since last April there was enough on the roads that anyone with crappy tires (including the crappy Bridgestone's I have on mine right now that still have 1-2 years left on them) would have problems getting around. Between using Auto and 4-Hi, I very much prefer it in 4-HI setting now over Auto. It seems to take a second or two for Auto to figure out which diff to engage where as in 4-Hi it's already locked in and away I go, no problems.

 

 

What's wrong with the Bridgestone tires? Mine do great in the snow and ice, they always did.

WilliamsVMAX Enthusiast

WilliamsVMAX

Posted
Posted

I live up in the Great White North, so I get to use to AWD/4Hi a lot in the winter. They best thing about the new trucks I find is that with the locking diff and stabitrak you hardly need to put it in AWD/4Hi. The systems together work so well its unbelievable. Sorry for getting off topic...

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