Question about 2002 Chevrolet Blazer

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Tranfer case does not shift into 4HI from 2WD

Previously able to shift into 4HI by manual procedure - no longer to do even that. Transfer case will shift into 4LO. Owners manual says the transmission indicator switch may require adjustment - how is this done?

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Try resetting the 4X4 module first. Remove the courtesy lamp and ATC fuses for at least 1 minute the reinstall fuses. Cycle key on and off 5 times then try your four wheel. Please rate if this works.

Posted on Dec 04, 2008

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I have a 93 jeep Cherokee, it will move in 4wh and in 4wl but will not go back into 2wd?

Hello guy
try posting what 4wd system you have,? first.
command trac or select track, (the latter is full time)
part time or the full time system,
we cant guess it....
read the operators guide first, if a part time system only
as i suspect, stop driving on dry pavement.
it's only for ice, or dirt. part time. part time is not a full time system.
shifting to 4wd on dry (means no ice) pavement causes, drive line wind up! and the gears to lockup. (see steering get tight in turns?> and is dangerous to drive it like this , you, me and the box)
posted here 100s of times.

the non grand Cherokee. early

had these choices
  • 1987-2001: New Process NP231 Command-Trac, part-time only, 2.72:1 ratio with low range
NP231 has the following settings: 2HI, 4HI, N, 4LO
  • 1987-2001: New Process NP242 Selec-Trac, full-time or part-time, 2.72:1 ratio with low range
NP242 has the following settings: 2HI, 4 full-time, 4 part-time, N, 4LO

as you can see you need to first know, what NP box you have or
photo your shift lever for 4wd, an post it and we tell you.

more facts, on select trac. (totally unlike command trac)
Selec-Trac locking hub is used on 4WD Cherokee. Selec-Trac
utilizes a non-disconnect front axle. Engagement of 2WD or 4WD is
accomplished at transfer case by means of mechanical shift linkage.
System allows full or part time 4WD. Selec-Trac can be shifted into
2WD or 4WD modes from inside the vehicle at any speed.
next from the service manual,
1) Place mode select switch in 2WD position. Transfer case
should shift to 2WD and not allow shifting into 4WD or LO range. Axle
should shift after transfer case shifts.
2) To determine if front axle has completed a shift out of
4WD into 2WD, position mode select switch back to 4WD position while
operating vehicle at slow speed. If vehicle shifts into 2WD, axle will
ratchet. If shift is not completed, transfer case will shift into 4WD
and hissing sound will come from mode select switch.
end quote.

if unsure read the FSM book its free.
shows you both systems and how to diagnose it.

in the box, click Cherokee,,then click 1993, and behold.
the real deal.


May 10, 2016 | Jeep Cars & Trucks

1 Answer

4hi worked yesturday on my 2002 envoy this morning i could only get 4low to work what could be wrong

you may have a bad switch ! i could tell you how to test it ,but could be fairly lengthy . do you own a volt meter ? do you know how to use one? should also check for dtc's in transfer case control module !
transfer case shift control switch indicator inoperative - one or more
the indicator lamps circuit consist of 5 individual lamps contained inside the mode/range switch assembly. the following lamps are contained inside the respective range button:
auto 4wd




each time the ignition is cycled, all 5 mode indicators light simultaneously, as an indicator check to ensure proper operation of the indicators. when the ignition is on, the transfer case shift control module illuminates the indicator lamp that corresponds to the current atc gear position, by providing a ground through a current limiting driver.
the transfer case shift control module flashes each indicator lamp after a shift has been requested and continues to flash until the transfer case shift control module completes the shift.
a solid state circuit, located inside the switch, supplies ignition voltage to the lamps. the solid state circuit also receives voltage when the headlamp switch is in the parklamp or headlamp position. when the solid state circuit receives voltage from the headlamp switch, the circuit reduces the voltage that is supplied to the indicator lamps, dimming the lamps when the headlamps are on.
test description
the numbers below refer to the step numbers on the diagnostic table.

  1. this step tests the transfer case electrical control of the lamp circuits.

  2. this step helps determine module failures.

  3. this step tests the affected lamp circuit for an open or high resistance.

  4. this step tests the lamp feed circuit for an open or short to ground.

these diagnostic procedures will help you to find and repair automatic transfer case (atc) system malfunctions. this service category also contains information for repairing atc system malfunctions. for best results, use the diagnostic tables and follow the sequence listed below:
  1. perform the diagnostic system check - transfer case. all atc diagnostics must begin with the diagnostic system check - transfer case. the diagnostic system check - transfer case determines the following:
  2. ?€¢
    proper service 4wd indicator operation

    ability of the transfer case shift control module to communicate through the data link connector (dlc)

    existence of atc dtcs

  3. refer to the diagnostic table as directed by the diagnostic system check - transfer case. the diagnostic tables help enable you to diagnose any atc system malfunction. bypassing these procedures may result in the following:
  4. ?€¢
    extended diagnostic time

    incorrect diagnosis

    incorrect parts replacement

  5. repeat the diagnostic system check - transfer case after you perform any repair or diagnostic procedure. this will verify that you correctly performed the repair. this will also ensure that other malfunctions do not exist.

Jan 21, 2015 | 2002 GMC Envoy

1 Answer

My 1997 GMC Sierra lights for 4hi and 4lo blink when i push the 4hi button and then goes back into 2hi. but when i push 4lo it locks in and works fine. I tried changing the 4wd motor on the transfer c

THE TRANSFER CASE MOTOR IS ONLY FOR 4WD LOW. That would have never been the problem as soon as you confirmed it shifted into 4wd Low. 2wd and 4 Hi work off of vacuum. You may have one or two issues. A vacuum leak up by the front axle that engages the 4wd HI or the sensors on the transfer case.

Nov 22, 2013 | 1997 GMC Sierra

1 Answer

1999 Chevy Suburban stuck in 4wd

Hi Dale, Sometimes the front diff becomes wound up. I am not saying this is the problem with your vehicle but what I'm about to suggest may work as it often does with other four by fours. Make sure you have a clear space to drive the vehicle backwards and forwards at a slow speed. As you do so select the two high position on the selector. You may need to reverse and go forward several times. Hope it works for you. Regards John

Aug 21, 2012 | 1999 Chevrolet Suburban

1 Answer

Car is stuck in 4wd low HELP!!!

Vehicles built After Jan 2002 may have Electronically Controlled Shift Mechanism. In the sorento's there are the switch knob eitheir if this one the auto or manual . If your Transfer case is difficult to shift or will not shift into desired range. 1) Transfer case electronically controlled shift system malfunction. 2) If vehicle was operated for an extended period in 4HI mode on dry surface, driveline torque load may cause difficulty. Drive the vehicle in a straight line and momentarily release the accelerator. The transfer case can then be shifted to the desired mode. 3) Insufficient or incorrect lubricant. 4) Internal transfer case components binding, worn, or damaged. Other possible causes are; Different Sized Tires; Charging System Diagnostic Codes; Transfer Case Control Module; INTERMITTENT WIRING AND CONNECTORS; Transfer Case Selector Switch; Transfer Case Mode Sensor; Mode Select Circuit open/shorted. At this moment, try putting it in nuetral and shifting your knob to the auto (ex models) or 2wd (lx) and see if it's click into your position, if not, check out your owners manual and follow steps. If you still can't get it unstuck, could be fuse relay or fuse that malfuctioned your control shift system, or simply the above mentioned. Would recommend you taking it in to your dealship to have them see what is causing the promblem.

Jan 28, 2011 | 2004 Kia Sorento

1 Answer

2001 Dakota: four wheel drive will not engage and windshield wi...

4x4 issue could be either the TCCM Transfer Case Control Module, or the transfer case shift motor.

When you turn your dash switch from 2wd to 4HI, can you hear the shift motor underneath operating?

May 17, 2010 | 2001 Dodge Dakota

1 Answer

02 dakota wont shift from 4hi to 2 hi

Try commanding the drive ranges while in netural cycling them. This may normalize the controller that senses the position from the encoder motor assembly. There maybe a procedure for that in a service manual.

Dec 12, 2009 | 2002 Dodge Dakota Club Cab

1 Answer

Transfer case oil

the transfer case uses the same ATF as the trans.

May 30, 2009 | 1999 GMC Jimmy

1 Answer

Will not shift into 4HI

These have a problem with grounds, i run a ground from my frame to transfer case

Dec 28, 2008 | 2000 Chevrolet Blazer

1 Answer

Can't transfer to 4L or neutral mode

Transfer cases can be quirky. I've got a 91 Wrangler, an 86 Cherokee and a 75 Blazer. When I go from 2WD to 4WD, they each have their own personality.

There are a number of things I've learned to persuade a stubborn xfer case to shift.

Try mixing these :
  • Engine running, vehicle not moving
  • Engine off, Shift Xfer case, Restart
  • Tranny in neutral
  • Shift Xfer case 'N', Tranny in gear, Tranny in neutral, Xfer case to 4HI or 4LOW (as long as you feel it register), Tranny in gear, try to move
  • Shift Tranny to Reverse, roll a few yards
  • Lock/Unlock the Hubs
To get back to 2WD:
  • Drive for a few feet in a straight line
  • Unlock the hubs
  • Tranny Neutral
  • Shift xfer case
Let me know how it turns out.

Jul 27, 2008 | 1991 Jeep Wrangler

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