4wd updates to ecm

BlueSS2003 · September 21, 2015

Guys,

I went into the dealer this Saturday for an oil change and when I went to pick it up the guy told me that they had went ahead and updated my ECM. He said there was a recall that the 4wd would randomly engage in cold temperatures. I tried looking around the forum to see if anybody posted this but didn't find anything, so I decided to post this for anybody that has a 4wd and has yet to get an update.

Texas weather is still hot, so I don't really have to worry about it though LOL.

nadrojcote · September 21, 2015

I believe they're referring to the transfer case recall.

newdude · September 21, 2015

Most likely. GM just added another Service Update Bulletin 15304 (not a "recall" but a when you take it into the dealer they will fix it kind of thing) for the transfer case cold weather performance. 819,587 trucks affected.

If it were a recall, you would have received a notice in the mail.

BlueSS2003 · September 22, 2015

Yeah that's what I told the service advisor, but apparently he didn't know what he was talking about.

firefighter907 · September 22, 2015

I just took my 2015 in for an oil change today and the service manager told me there was 2 recalls on the truck. One was a reflash of the TCU for an issue where the transfer case does not always come out of 4WD when switched back to 2WD, and the other was to check the mounting fasteners on the rear calipers for proper tightness. I guess I should have asked for the TSB numbers.

shopworld · September 22, 2015

+1

This is a pending recall, our dealer had a "notice" but did not have more detail on it, or a fix for it yet (9/19/2015), said to come back by Nov when the weather turns and they will have the fix from GM and take care of it

jmbroussard05 · September 25, 2015

I had my truck in today for scheduled service and they performed the Recal 15304. On the service document it listed it as Recall 15304, for the Transfer case issue. Not much information out there on it though other than saying what the guys above already have said.

OldDawg45 · September 27, 2015

This is a recall ....

This bulletin provides a service procedure to reprogram the transfer case control module on the vehicles listed above. In low ambient temperatures, below 5°F (-15°C) a transfer case brake motor assembly malfunction may occur. Diagnostic Trouble Code (C0398 - Range Position Correlation Fault) will be set, locking the transfer case in “4HI” until the vehicle is serviced. This software update also addresses other transfer case control issues for overall improved drivability.

redwngr · September 27, 2015

There were many posts about the t case issue last winter.

Good to hear that there is now a solution available.

tnchevy · September 27, 2015

It is still not listed under the recall webpage on GM"s website when I put in my VIN #

cev103 · September 27, 2015

I had it done last week when I went in for an oil change.

TenofMe · September 29, 2015

I had it done, too. And not to get anyone's hopes up, but it drives like a different truck now. And before anyone starts, I noticed the change in the way it drove before I even knew they performed the update. Shifts were much more immediate. No more flaring, either. Power always seems just under foot, right at tip-in.

It wasn't until I got home and was filing the service receipt that I noticed the transmission software update had been performed. They said nothing about it at the dealership. I'll post the service order later.

I have no idea what the "improved driveability" part of the fix was, but I literally thought I was driving a different truck. Throttle response is now instant. On the highway, hitting the gas causes an immediate downshift and hard acceleration. NOTHING like before.

I thought it was the gas. I ran the tank dry and put in regular 87. No difference. It runs better now than it did before on premium. Not once in 4 days has it felt like it was "hunting" for the right gear.

I HONESTLY don't think it's in my head. I had a 2014 SLE crew Z71 with a 5.3, and now I have a 2015 SLT crew z71 w/5.3 . Neither truck ever ran this way. I experienced all the problems everyone else has reported. And I just turned in a service loaner 2015 Silverado crew 2WD w/5.3, and the difference was night and day.

Has anyone else noticed anything like this? I had the service performed last Friday the 25th. I'll post the TSB number later when I get home.

tbarn · September 30, 2015

OK, the "recall" is a transfer case software update only. They either programmed the wrong module ( to your benefit apparently) or did two module procedures. And it is not a recall or you would get a letter from GM telling you to bring your truck in to get it fixed. It is a "service update campaign". It's only free under the New Vehicle Limited Warranty coverage period. It's not hard as you might think to program a different module than you intended. Especially on a smaller laptop screen. There are two lines for transfer control module programming and setup and guess what the the next one down is, transmission control module. It happens.

Silverado-Hareek · October 12, 2015

I had this work done today on my truck actually. I took it in for an oil change/tire rotation and the rep informed me there was a "Recall" that just came out for the transfer case. He said it was a software update. While the paperwork calls it a recall, it also says "Expires with base warranty" which tells me it's not an official recall but a service update that is only free because it's under warranty.

The full text is:

"Recall 15304 4WD ALWAYS ENGAGED IN COLD TEMP

EXPIRES WITH BASE WARRANTY

UPDATED CALIBRATION

TRANSFER CASE SHIFT CONTROL MODULE REPROGRAMMING WITH SPS 9101695 .4"

I haven't noticed anything different with regards to the drive-ability or the performance of the truck. Seems just as normal as when I dropped it off this morning.

zert100 · October 14, 2015

I had this work done today on my truck actually. I took it in for an oil change/tire rotation and the rep informed me there was a "Recall" that just came out for the transfer case. He said it was a software update. While the paperwork calls it a recall, it also says "Expires with base warranty" which tells me it's not an official recall but a service update that is only free because it's under warranty.

The full text is:

"Recall 15304 4WD ALWAYS ENGAGED IN COLD TEMP

EXPIRES WITH BASE WARRANTY

UPDATED CALIBRATION

TRANSFER CASE SHIFT CONTROL MODULE REPROGRAMMING WITH SPS 9101695 .4"

I haven't noticed anything different with regards to the drive-ability or the performance of the truck. Seems just as normal as when I dropped it off this morning.

Same here. I was hoping it would help with the low speed clunk, but it did nothing to improve the drivability of my truck.