4WD Service message - I had recently done Dyno test on my truck. The person performing it had removed the 4WD/Trac fuse out. and after reinstalling the fuse I still get the message? fuse looks fine.

4WD not working on 2001 explorer sport

Ford-Trucks.com https://www.ford-trucks.com > forums > 1211319-4w...
Dec 21, 2012 - I had a similar problem with no response from 4x4 toggle (2004 Sport Trac), but fuse was blowing. Turned out to be the 4x4 transfer case shift ...

2001 Sport trac 4wd problems - Ford Truck Enthusiasts Forums
Jan 23, 2007
01 Sport Trac 4WD won't Engage - Ford Truck Enthusiasts
Dec 29, 2009
2001 sport trac... 104000miles 4x4 low no workie
Dec 26, 2014
2001 Sport Trac 4WD Problem - Ford Truck Enthusiasts Forums
Dec 11, 2005
More results from www.ford-trucks.com

2001 Sport Trac 4x4 does not engage.

Explorer Forum https://www.explorerforum.com > forums > threads
Mar 23, 2020 - First try unplugging the module and cleaning with contact cleaner and plugging back in a few times and see if that helps. That trick didn't work for me but it's ...

4x4 light not working/won't engage into 4wd
Mar 22, 2020
4 wheel drive not engaging ' Ford Explorer Forums
Mar 26, 2020
4WD Not engaging?????PLEASE HELP????
Mar 23, 2020
2nd Gen 4wd Troubleshooting Guide ' Ford Explorer Forums
Mar 29, 2020
More results from www.explorerforum.com

..

Which transfer case does it have ????

Is the service light on ?
SERVICE indicator (4WD/AWD) Lamp
The SERVICE indicator (4WD/AWD) lamp is an integral part of the cluster and cannot be serviced separately. This lamp is used to inform the driver of the vehicle of malfunctions within the automatic transfer case (ATC) system. The SERVICE indicator (4WD/AWD) lamp is controlled by the transfer case shift control module via CKT 1567.
Circuit Description
The ignition switch supplies Ignition 3 voltage to the transfer case shift control module at connector C1 terminal E10 using the 4WD Fuse. When the ignition switch is first turned to the RUN position, the transfer case shift control module responds by flashing the SERVICE indicator (AWD/4WD) lamp for approximately 2 seconds, then turning it OFF, while performing tests on the ATC system. The transfer case shift control module will continue to perform tests on the ATC system during a normal drive cycle.

Hooking up a factory or some other professional scan tool that can view DTC'S - diagnostic trouble code's in the 4X4 control module would be the best way to find the problem.

DTC B0768 Service Indicator Circuit High
DTC B2725 ATC Mode Switch Circuit Malfunction
DTC C0300 Rear Speed Sensor Malfunction
DTC C0305 Front Speed Sensor Malfunction
DTC C0308 Motor A/B Circuit Low
DTC C0309 Motor A/B Circuit High
DTC C0310 Motor A/B Circuit Open
DTC C0315 Motor Ground Circuit Open
DTC C0323 T-Case Lock Circuit Low
DTC C0324 T-Case Lock Circuit High
DTC C0327 Encoder Circuit Malfunction
DTC C0357 Park Switch Circuit High
DTC C0362 4LO Discrete Output Circuit High
DTC C0367 Front Axle Control Circuit High
DTC C0374 General System Malfunction
DTC C0376 Front/Rear Shaft Speed Mismatch
DTC C0387 Unable to Perform Shift

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.
Command-Trac
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.

http://www.rubicon-trail.com/4WD101/driveline-bind.html


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.
unquote
next from the service manual,
4WD TO 2WD
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.

http://www.morris4x4center.com/knowledge-base/index.htm?utm_source=cj#service

You need to take it to a repair shop that knows this system an has a diagnostic tool to scan for codes . These systems are very complex an your average person with out training should not attempt to fix it.
Traction Off The IPC illuminates the traction off indicator when the following occurs:
?€¢
The electronic brake control module (EBCM) inhibits the traction control system. The IPC receives a class 2 message from the EBCM requesting illumination. The traction control system is disabled when the following occurs:

-
For Chevrolet only, the shift lever is in FIRST (1) or SECOND (2) gear. The EBCM receives a class 2 message from the powertrain control module (PCM) indicating the gear position.

-
For Pontiac and Oldsmobile only, the body control module (BCM) detects that the traction control switch is pressed (signal circuit is low). The EBCM receives a class 2 message from the BCM indicating the switch status.

-
The BCM detects that the park brake is engaged (signal circuit is low) and that the engine is on. The EBCM receives a class 2 message from the BCM indicating the park brake status.

-
The PCM detects certain malfunctions and is unable to perform torque reduction requests from the EBCM. The EBCM receives a class 2 message from the PCM indicating that traction control cannot be performed.

?€¢
The EBCM detects a malfunction in the traction control system. The IPC receives class 2 messages from the EBCM requesting illumination of both the service vehicle soon and traction off indicators.

?€¢
The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.

With the light lit there are DTC'S - diagnostic trouble codes stored in the EBCM -
TRAC OFF
Traction Off: Refer to ABS Description and Operation in Antilock Brake System

remove the HVAC fuse from the underhood fuse block. Wait 60 seconds. Reinstall the fuse. Turn the key to the run position, do not start. You should here the actuators running through there self test. After about a minute or two it should be all done.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

There is a TSB on this problem: TSB #03-04-21-001C

Subject:4WD Switch Indicator Lights Flashing, 4WD Inoperative, DTCs C0327, P0500, P0836, P1875 Set (Replace Encoder Motor Sensor, Reprogram TCCM, Inspect Front Drive Axle Engagement Sleeve for Damage/Repair) #03-04-21-001D - (12/04/2003)



Models:2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003 GMC Sierra, Yukon, Yukon XL
with 4WD and Electric Shift or Active Transfer Case (RPO NP1 or NP8)
You can also try removing the TREC fuse (engine fuse box) and reinstall after 30 seconds. Look up the TSB number I gave you and you'll find alot more information.

• Pry the plate around the radio/heat controls off.
• Disconnect the 4WD switch connector at the switch.
• Disconnect the foglight switch connector at the switch.
• Disconnect the rear wiper switch connector at the switch, if equipped.
• Remove the panel surrounding the cluster itself. Bolts above the steering wheel in the shroud.
• Remove the instrument cluster. Should be four bolts.
• If you have an illumination bulb out, replace it with a #194 or a #168 bulb.
• If you have a warning light out, replace it with a PC74 bulb.
• Installation is reverse of removal. TEST BEFORE YOU PUT EVERYTHING BACK IN.

You're done.

You can get a Dyno tune done at a speed shop. Drive down to the local speed shop and they would know the best guy's in town to Dyno tune your engine.
You can work with the tech to tune your toyota the way you want it to perform. Can change the shift points to the transmission, RPM limit, and speed limit too. 
Going to keep it simple so do the K&N filter, good spark plugs and wire, and Dyno tune. 
Good luck and keep me posted. be glad to answer more questions

Behind the kick panel on the passenger side is an electronic box. unplug the wiring harness and inspect for corrosion, clean and reconnect.

The trac light does NOT come on for the smog test. It has noting to do with the smog test. The trac light DOES come on when the Check Engine light comes on, when a failure is detected. From what I remember, the trac light WILL come on if the smog is a "dyno-driven" smog test, but it has nothing to do with the test, the trac simply comes on because only one wheel is spinning, just like it will when you are spinning on ice.. Hope this helps.