I pull my fiver up to Wiscassett Maine over the weekend..about 200 miles..pull into camparea to setup..pretty muddy from alll the rain...DIC shouts out i..4wd needs service. 4wd operates fine in 4 lo and 4 hi. whats this crap?? ..did the same thing last fall coincidently at the same place..weird....http://dieselplace.com/forum/smileys/Angry.gifhttp://dieselplace.com/forum/smileys/Disapprove.gifhttp://dieselplace.com/forum/smileys/Dead.gif


anybody know whats going on here ?? later, bc

I would take it to the dealer to read the codes if you are under warranty.

what did the problem end up being last time??? or did you never take it in??

It might be a wheel speed sensor, I know of you loose one it will kick the service 4wd light on.

thanx for the input fellas, polarbear - the last time i took it to the shop and they said...no codes set..current or history..whatever the hel that is ! sometimes i wish it were an older rig..one i can work on..


max..it is under warranty and will bring it in to be ck'd out..tks, bob

There are some updates to the software for some 4wd issues. It wouldn't hurt to get it updated.

this could be a possible cause
<HR>




<H1>Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System (Reprogram Transfer Case Control Module Using Labor Operation Code N8521) #02-04-21-006D - (03/24/2004)</H1>


Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System (Reprogram Transfer Case Control Module Using Labor Operation Code N8521)


2004 Buick Rainier


2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT


2003-2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe


2002-2004 GMC Envoy, Envoy XL


2003-2004 GMC Sierra, Yukon, Yukon XL


2004 GMC Envoy XUV


2002-2004 Oldsmobile Bravada


with Electronic Shift or Active Transfer Case (RPOs NP1, NP4 or NP8)


This bulletin is being revised to add information to Step 5 of the procedure. Please discard Corporate Bulletin Number 02-04-21-006C (Section 04 -- Driveline/Axle).<A name=ss1-1481410><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1481410&amp;pubid=297&amp;evc=sm#ss1-1481410" target="_blank">
<H5>Condition</A></H5>


Some customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, or the 4WD/AWD system may be inoperative and/or the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up.<A name=ss2-1481410><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1481410&amp;pubid=297&amp;evc=sm#ss2-1481410" target="_blank">
<H5>Cause</A></H5>


The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".


When the TCCM is in the "sleep mode", it will not communicate with the class II bus or the Tech 2®.<A name=ss3-1481410><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1481410&amp;pubid=297&amp;evc=sm#ss3-1481410" target="_blank">
<H5>Correction</A></H5>

<LI =1>Try to communicate with the TCCM. If no communication, go to step 2. If communication is possible, go to step 5.
<LI =1>Remove the underhood (ATCM or TREC) TCCM fuse.
<LI =1>Wait 30 seconds.
<LI =1>Reinstall the fuse. The module should "wake up" and communicate with the Tech 2®.
<LI =1>Check for codes in the TCCM. If a C0550 is found current or in history with or without other codes, replace the module and go to step 6.
<LI =1>Reprogram the TCCM using normal SPS procedures, using TIS software version 3 released March 8th, 2004 or newer.
<LI =1>Verify operation and that no codes are present. </LI>



<H4>Important</H4>


For the 2002 Model Year, the TCCM must be replaced and recalibrated.


<A name=ss4-1481410><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1481410&amp;pubid=297&amp;evc=sm#ss4-1481410" target="_blank">
<H5>Warranty Information</A></H5>


For vehicles repaired under warranty, ONLY use Transfer Case Control Module (TCCM) Labor Op-Code N8521.



<TABLE width="100%" border=1>
<T>
<TR>
<TH vAlign=bottom align=middle>


Labor Operation</TH>
<TH vAlign=bottom align=middle>


Description</TH>
<TH vAlign=bottom align=middle>


Labor Time</TH></TR>
<TR>
<TD vAlign=center align=middle>


N8521</TD>
<TD vAlign=center align=middle>


Module, Transfer Case Control (TCCM) - Reprogram </TD>
<TD vAlign=center align=middle>


0.4 hr</TD></TR>
<TR>
<TD vAlign=center colSpan=3>


For additional information on using Labor Op-Code N8521, refer to Corporate Bulletin Number 02-06-04-057 (SI Document ID# 1406011). </TD></TR></T></TABLE>

also a bulliten to replace the transfer case encoder motor sensor.its a true fix and not hard to do...

Mine did the same thing this morning. It wouldn't let the alli go into gear and the abs and park brake lights came on...I spent this afternoon going back to stock, well as close as I can get. My dealer's cool with mods, but better safe than sorry...

as far as your abs and brake light goes
<H1>Advance Service Info - Antilock Brake System (ABS) Light On, Service Brake System Message On Driver Information Center (No Fix At This Time) #04-05-25-005 - (04/07/2004)</H1>


Antilock Brake System (ABS) Light On, Service Brake System Message on Driver Information Center (No Fix At This Time)


2003-2004 Chevrolet Silverado 2500/3500 HD Series Pickups


2003-2004 GMC Sierra 2500/3500 HD Series Pickups<A name=ss1-1491723><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1491723&amp;psdid=437&amp;evc=sm#ss1-1491723" target="_blank">
<H5>Condition</A></H5>


Some customers may comment that the ABS light, Service Brake System message comes on intermittently during initial start-up. The condition does not cause a DTC to be stored permanently.<A name=ss2-1491723><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1491723&amp;psdid=437&amp;evc=sm#ss2-1491723" target="_blank">
<H5>Cause</A></H5>


The cause may be a timing issue related to the cranking / starting of the vehicles. It appears that the condition is more likely to occur on vehicles with diesel engines, though it can occur on vehicles with gasoline engines as well.<A name=ss3-1491723><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1491723&amp;psdid=437&amp;evc=sm#ss3-1491723" target="_blank">
<H5>Correction</A></H5>


DO NOT REPLACE THE ABS MODULE.


DO NOT attempt to repair these vehicles at this time.


Engineering is currently working on a software fix to address this condition and dealers will be notified as soon as that fix becomes available.


General Motors encourages dealers to share this information with concerned customers.<A name=ss4-1491723><A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=1491723&amp;psdid=437&amp;evc=sm#ss4-1491723" target="_blank">
<H5>Dealer Action</A></H5>
<UL =BULLET>
<LI>Record the customer information on a permanent record so you may call the customer when a repair becomes available.
<LI>Advise the customer that a repair is in test and validation and is due out soon. At the time the bulletin becomes available, it will be the dealer's responsibility to contact the customer. </LI>[/list]

LOL inopertive 4wd may be due to "not recieving the wake up call" and is still in "sleep mode"


I feel that way sometimes in the morning too http://www.dieselplace.com/forum/smileys/Approve.gif

Ditto!http://www.dieselplace.com/forum/smileys/Sleepy.gif

Service mgr says to bring it in and get a latest download of current updated software..also said theres a known ground problem that they will address. bc

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window.onload = () {
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Took a trip to the dealer today, No codes.... It all just diappered like a fart in the wind....WTF!!!





Ox

UNBUWEEEVUBUL !!!http://www.dieselplace.com/forum/smileys/Clown.gif

Bob,
The “Service 4WD” error was a common problem on the 03’s. Mine behaved like what you are describing. The owner's manual says it's OK if the DIC message goes away after a shutdown and restart. If it keeps coming back you should insist that they (the dealer) fix it. I took my 03 in for the "Service 4WD" problem when the truck was a year old with 18kmi. Prior to this I had experienced 2-3 "Service 4WD" messages. Each time the message didn't return after a shutdown/re-start and the 4WD worked fine. Per the owners manual this is "normal". However, at one point the problem did not go away. I had taken a 5-hour trip and when I arrived at my destination I had the "Service 4WD" message. This time the message would not go away after a shutdown &amp; restart, but it would clear by pressing one of the DIC info buttons on the steering wheel. At this point the message continued to come on and stay on. The 2W, 4WH, 4WL and neutral indicator lights were also coming on randomly and now the 4WD did NOT work. Seeing the 4WLo light come on when I started up was not a good feeling… The dealer found three codes and said the encoder motor needed to be replaced. They had to order the part and wanted to keep the truck because they said it may get stuck in 4WL/H but I asked them to just remove the fuse so I could use the truck until the part came in. A few days later the dealer installed a new encoder motor and re-programmed the TCCM. The service writer told me that in spite of what the owner’s manual says, they always repair the problem as soon as even one "service 4WD" message shows up. He also said they always replace the whole encoder motor assy, not repair it. He said they had one customer with a truck stuck in 4WL that drove it (in 4WL) on the highway and burned out the transfer case.
TSB #03-04-21-001C - (06/24/2003) (http://dieselplace.com/forum/forum_posts.asp?TID=277&amp;KW=service+4wd) (posted by Dmaxallitech in the TSB forum) is the one that addressed the problem with my truck.
“4WD Switch Indicator Lights Flashing, 4WD Inoperative, DTCs C0327, P0836, P0500 (Replace Encoder Motor Sensor, Reprogram TCCM, Inspect Front Drive Axle Engagement Sleeve for Damage/Repair if Necessary”
http://www.dieselplace.com/forum/smileys/Geek.gif

Well I got the "service 4 wheel drive" message again so I took another trip to the dealer. There were a couple drive-train codes, don't remember what. Then he checked the body codes, there was a ton of body codes. A whole bunch of them were non communication codes. So I went home broke out the Helm's manuals and tore into it. Almost all of the wires from the steering column go into one plug similar to the CAN-BUS where the juice plugs in. Well one of the posts wasn't in the bail. I figure this was overlooked during assembly and took a year to work loose. I unplugged it and plugged it in right. Now all is well. Now I can get all the codes cleared and put all the goodies back on.

Take Care,

Ox