Bravada Smart Track Problem?

[matt_o_70]

I have a 2000 Bravada that is fairly new to me. The problem that I need the most help with is the smart track is engaged at all times.

 

I have pulled the "4WD" fuse and test driven and can then instantly feel that the truck is now in 2WD as it should be. I do not have any MIL showing any problems but have not had it scanned for any codes.

 

1) Tires are well worn but are all evenly worn across the set.

2) tire pressure is correct.

3) I have done the blue autotrac transfer case fluid change already since the PO acknowledged the car did bind when making very tight parking lot turns. He was given a bit of the run around trying to get it fixed.."they all do this" etc..

 

I have no previous GM experience but I worked for a toyota dealer for 6 years (ASE mastertech) in my previous career. This is my first personal car new enough to be an OBD2 car so until now I have not had any reason to own a scan tool. Will the affordable scan tools allow you to see any codes that pertain to the drive line? I assume that if the encoders/speed sensors were totally bad there would be a MIL of some kind?

 

How sensitive are these vehicles to tire wear? I don't want to put on new tires until this problem is fixed - but it would be ironic if worn tires was the cause of these problems?

Is there a spec for allowable tire diameter variation?

 

looking for some insight from experienced techs who have fixed the smart track systems. 1) Is the TCCM looking at encoders in the transfer case?

2) If so are there 2 - one for each drive shaft?

3) Since it seems that the transfer case motor engages and disengages with the fuse pulled. Is it safe to say the problem is elsewhere?

4) since there are no "service AWD" or CEL is is safe to assume that the TCCM "BELIEVES" that the encoderes are working properly?

 

Where should I look next?

 

Matt

[matt_o_70]

OK thanks for the schematic's and the history guys.

 

What is most annoying is since driving for a few days with the 4wd drive fuse removed and then reinstalling the fuse it appears that everything is now fine (for the moment).

 

With the fuse removed I could instantly feel that It was in 2wd for the first time. We are getting a pile of snow today, so tomorrow I am sure that I can get the AWD to engage and will get to test things for normal engagement and disengagement.

 

I just hate it when a problem "goes away" I'd much rather find a problem and then fix it. I did change the autotrak fluid since I aquired this truck and so if these clutch packs have a history "sticking" - I guess it's now freed up.

 

The scan tool I have will show live ecu data and enhanced DTC's but it is not pricey $$ enough to show live driveline speed sensor readings (that would be sweet for $150). If it acts up again I will run by a shop with a T2 and see what it comes up with.

 

good luck with your testing.

[gmtech4]

glad we could help a little,at least you have something to go by if acts up,we are experiencing no snow here except the melting kind here in Alberta,lol,sorry ,could not resist,keep us posted

[gmtech4]

thats what makes sense,goin to school tomorrow for anti lock certification,gonna bring my laptop,maybe teacher can figure out why laptop does not like passthru programing,to the big city of Calgary,2hr drive,no big deal

[matt_o_70]

I'd be interested to know what the VIN report shows?

1GHDT13WXY2162405

[gmtech4]

I'm using it to see what t case you have

[gmtech4]

1) With out any MIL would you expect to find codes?

 

2) Any comment on the scan tools - I have been waiting for an excuse to get one for personal use, this looks like it. Will the consumer tools give access to all codes that are stored?

 

Or when you say "get it scanned" do you mean take it to a shop with a tech2 for any or all TCCM drive line have messages?

 

I answered this already today but it didn't go thru,so jobber scanners should read all codes,I have never used 1,only the tech 2,they are awsome and very expensive @$3000.,I do expect to see a code,may be someone else can chime in here about jobber scanners

[gmtech4]

here is your warrenty history just because.

CLAIM HISTORY

R.O Date R.O Number Type Labor Operation Odometer Reading

08/15/2005 041417 B D0362 - CONTROL, HEATER AND AIR CONDITIONING - REPLACE 75784 miles

06/07/2002 051429 # V0842 - INSPECT AND REPLACE HAZARD WARNING FLASHER SWITCH 34712 miles

06/07/2002 051429 # E2927 - BALL JOINT, CONTROL ARM - UPPER - BOTH - REPLACE 34712 miles

06/07/2002 051429 # E2937 - BALL JOINT, CONTROL ARM - LOWER - BOTH - REPLACE 34712 miles

01/11/2002 047257 # E7960 - IDLER ARM REPLACEMENT 27204 miles

01/11/2002 047257 # J3177 - LINE AND/OR HOSE, ENGINE OIL COOLER - BOTH - REPLACE 27204 miles

01/11/2002 047257 # E9050 - POWER STEERING PUMP REPLACEMENT 27204 miles

04/03/2001 039171 # J3176 - LINE AND/OR HOSE, ENGINE OIL COOLER - ONE - REPLACE 9701 miles

04/03/2001 039171 # Z5001 - VIP FREIGHT/POSTAGE REIMBURESEMENT 9701 miles

03/26/2001 038884 # K5390 - LINES AND/OR FITTINGS, TRANSMISSION OIL COOLER - UPPER - A 9524 miles

03/26/2001 038884 # Z5001 - VIP FREIGHT/POSTAGE REIMBURESEMENT 9524 miles

03/03/2000 028113 # F1447 - SEALS, FRONT DIFFERENTIAL OUTPUT SHAFT - FRONT - BOTH - RE 7 miles

12/02/1999 025490 # J0966 - ADAPTER AND/OR GASKET, OIL FILTER PIPE - REPLACE 6 miles

12/02/1999 025490 # Z5001 - VIP FREIGHT/POSTAGE REIMBURESEMENT 6 miles

09/27/1999 262405 I Z7000 - PRE-DELIVERY INSPECTION - BASE TIME

[gmtech4]

I'm just going to cut and paste some info for you.

--------------------------------------------------------------------------------

 

Transfer Case Description

New Venture Gear 136 Automatic Transfer Case

 

 

 

 

The NV136 transfer case is an automatic transfer case with two drive ranges. Shifting from rear wheel drive to four wheel drive is done automatically when the transfer case shift control module receives wheel rotating slip information from the speed sensors. The transfer case shift control module then engages the transfer case motor/encoder to position the transfer case from rear to four wheel drive. When the transfer case shift control module receives information that the wheel rotation is the same on both axles, the transfer case shift control module sends position information to the motor/encoder to put the transfer case back into rear wheel drive. The 2HI position is for normal driving with the rear wheels pushing the vehicle. The 4 wheel drive position is for driving through sand, snow, mud, gravel, or heavy rain at normal or slightly below normal speeds. The NV136 is manufactured at Syracuse New York by New Venture Gear a division of New Process Gear for General Motors.

[gmtech4]

I'm going to try copying & pasting the schematic

 

 

,didn't work,I sent them to you thru gm trucks

[gmtech4]

well still locked out ,i'll get it fixed,try tonight

[gmtech4]

here is your options also.

 

OPTION CODES

AG0 - POWER 8-WAY DR SEAT WITH MEMORY AH8 - POWER 8-WAY PASS SEAT W/MEMORY

AJ1 - DEEP TINT PRIVACY GLASS AN3 - FRONT BUCKET SEAT PACKAGE

AP9 - TRUNK CARGO NET AU0 - KEYLESS REMOTE LOCK CONTROL SYS

AU3 - POWER DOOR LOCKS AXP - MPV-VIN IDENT POSITION

A31 - POWER WINDOWS W/DR AUTO DOWN B30 - CARPET FLOOR COVERING

B84 - MOLDINGS-BODY SIDE CF5 - ELECTRIC SLIDING GLASS SUNROOF

C25 - REAR WINDOW WIPER SYSTEM C3T - GVW RATING 5350 LBS

C49 - ELECTRIC REAR WINDOW DEFOGGER C68 - AIR COND-ELECTRONIC CONTROL

DAY - GM TRUCK & BUS-MORAINE,OH PLANT DD0 - DRIVER OUTSIDE ELECTROCHROMIC MIRROR WITH DEFOG FEATURE

DD8 - MIRROR-INSIDE,LIGHT SENSITIVE DH6 - DR/PASS ILLUM VISOR MIRRORS

DK8 - INTERIOR ROOF CONSOLE D07 - FRONT SEAT FLOOR CONSOLE

D96 - UPPER BODY SIDE STRIPE EVA - EVAP EMISSION REQUIREMENT-TEST

FF6 - TORSIN BAR SPRING ADJ FF7 - TORSIN BAR SPRING ADJ

F46 - ALL WHEEL DRIVE CHASSIS GT4 - FINAL DRIVE RATIO 3.73

G80 - DIFFERENTIAL POSI-TRACTION JC1 - POWER 4-WHEEL DISC BRAKES

KA1 - HEATED SEAT K18 - AIR INJECTION REATOR SYS-ELECT

K34 - ELECTRONIC CRUISE CONTROL K60 - GENERATOR-100 AMP

L35 - ENGINE-4.3 LITER V6 WITH CPI M30 - TRANSMISSION-4 SPEED AUTO

NC1 - CALIFORNIA EMISSION SYSTEM NG1 - NORTHEAST EMISSION EQUIPMENT

NP4 - ACTIVE TRANSFER CASE NP5 - LEATHER STRNG WHL & SHIFT KNOB

N33 - STEERING WHEEL W/TILT FEATURE N40 - POWER STEERING

N90 - 15" CAST ALUMINUM WHEEL QBG - P235/70R15 WHITE LETTER TIRES

RSA - FRONT SEAT RESTRAINTS RYJ - RETRACTABLE CARGO AREA COVERING

R6E - RESTRICTION BYPASS - ALL MODELS R9B - OPTION IDENTIFIER

R9S - WARRANTY STATEMENT ALL MODELS SLM - SALES STOCK ORDERS

TB4 - LIFT GATE T37 - FOG LAMPS

T61 - DAYTIME RUNNING LIGHTS UA1 - HIGH CAPACITY BATTERY

UK3 - STEERING WHEEL W/RADIO CONTROLS UP0

UP8 - RADIO PROVISIONS UY7 - HEAVY DUTY TRAILER HARNESS

U1Z U16 - TACHOMETER

U73 - ANTENNA-FIXED MAST VR4 - WEIGTH DISTRIBUTING HITCH

VXS - VEHICLE COMPLETE V54 - ROOFTOP LUGGAGE CARRIER

V73 - STATEMENT OF VEHICLE CERT- U.S. XBG - P235/70R15 WHITEWALL TIRES

YBG - P235/70R15 WHITEWALL TIRES YD3 - AXLE (BASE EQUIP) FOR GVW PLATE

YD5 - SPRING-FRONT-BASE EQUIPMENT YD6 - SPRING-REAR-BASE EQUIPMENT

ZBG - P235/70R15 TIRES ZM8 - SALES PKG-ELEC TAILGATE RELEASE

ZQ3 - SALES PKG-DRIVER CONVENIENCE II ZQ6 - SALES PKG-DRIVER CONVEN III

ZW7 - PREMIUM SMOOTH RIDE CHASSIS PKG ZY1 - COLOR COMBINATION SOLID

Z70 - OLDSMOBILE NAME PLATE-CONVERSN Z82 - TOWING PACKAGE

1SA - OPTION PACKAGE 1SA 1SZ - TOTAL PACKAGE SAVINGS

12I - GRAPHITE INTERIOR TRIM 122 - TRIM-GRAPHITE LEATHER

6WH - COMPUTER SELECTED SUSPENSION 7WH - COMPUTER SELECTED SUSPENSION

86U 91A - GRAY

[matt_o_70]

I need your VIN Matt

 

1GHDT13WXY2162405

 

ARGH! -editied to add missing digit

[gmtech4]

VIN is missing a digit,need 17 ,does not compute on GMVIS,lol,

[matt_o_70]

I picked up a scan tool. It is surprisingly nice tool (Innova 3130). No DTCs stored!

[gmtech4]

I need your VIN Matt