Why is the service 4WD message on all the time and diff lock light flashes and dos not lock?

2003 Trailblaze LS 4WD problems ,but what 4wd option was installed new, the VIN + RPO list tell tells that
what are you tires touching, ICE, dirt or snow or hard pavement.????????????
first time you using 4wd or only this truck first time ever, no history told
the RPO code is NP8 for some version of this car the VIN code will tell you RPO list. and what box is here.


246 is yes FULL TIME and 6 and end means computer control wet clutch in the box.
they used 5 different transfer cases that model. care. so says GM parts oem online

avoid 4Low until you learn its limits,and avoid any selection called lock center differential tires on pavement

wow no year told at all, nor county car was sold first or VIN/
toyota Previa, also known as the Toyota Estima
1990 to 2019, must we guess that and what transfer case is there?
fire them all, find a real 4wd only shop
first off if 4wd means (IDK never seen this car in USA) zero books
if that is part-time 4wd or is AWD with center DIFF set to lock
well that is illegall usage on dry pavement..
did kids play with your car? how did it get to 4wd in the first place?
is the steering acting up, fighting you?????????????
to exit 4wd (PT) put one tire, on sand.grass,ice,gravel but not on any kind of pavement and move like a snail and shift out of 4wd. BINGo!
what country is this, we can not guess that, nor what models they sold and options 4wd they had there .,
there are vast kinds of 4wd made, AWD and mix, yes mixed
the AWD cars are full time 4wd/AWD, and with a center differental
that allows magically AWD to work on all road but not IN LOCK MODE>
in that mode you must be off road or on ice.
ok?
wiki shows like 100 sub-models if the car, overwhelming this.is,
lost your users guide in the glove box."?? and how to use 4wd is there ,if lost buy one and read 4wd sections with care.

some 4wd have no 4wd levers as seen ww2 jeep 1941 to now.
some have electric solenoid only controls that fail
and for sure on paved hard dry road,s
no solenoid on earth can pull the gear out of gear, if on pavement and you have 4wd fully wound up in this illegall sate.!!! fail it well
many shops never seen PT 4wd in their lives. as seen here on vast jEEPS, I have a Wrangler with that and now how to use in on all kinds of roads, even way way off road..
the wiki shows AWD car.same. go AWD?
some Australian versions are 4wd only means no AWD at all
all wheel drive is called ALL trac. by maker.
also made as a hybrid. again no year told so fail me.
is your car in JAPAN and you there speaking English
wow if yes.
the wiki is super complex on this car lacking a year
and for sure location and driveline options NOT TOLD.
and what transfer case is there, awd or 4wd only
my wild guess lost the owner guide the glove box.
for sure what not to do 4wd or in AWD lock mode.

AWD is 4 wheel drive with a diff in the transfer case to allow for uneven running between front and rear axles
If you have a 4wd drive button then that simply locks the centre diff so that there is no equalization of differences in the front and rear axles

awd will be working all the time and is not accessible or changeable. The 4wd bit comes into play when 4wd is selected at the switch or lever and if locks the Centre diff (awd diff) to make both front and drive shafts turn as one.
Check with a workshop manual to see how it works and where the problem may be.

AWD vehicles have a centre diff in the transfer case and if there is no traction on the rear wheels then the front wheels will not turn. All wheel drive is not equal to 4 wd which you assume apparently. Check that there is not a diff lock button in the car to lock the centre diff turning it into 4wd vehicle in which case the front wheels would have moved the vehicle

change what isnt working one at a tiome..

Page 13 of owner's manual says:
AdvanceTrac
(if equipped):
Illuminates when the AdvanceTrac
system is active. If the light remains
on, have the system serviced
immediately.
AWD locked (if equipped):
AWD
Illuminates when all wheel drive
LOCKED
(AWD) is engaged/activated. If the
light continues to flash, have the
system serviced.

Page 224:
ALL WHEEL DRIVE (AWD) SYSTEM (IF EQUIPPED)
Your vehicle may be equipped with an All Wheel Drive (AWD) transfer
case. With the AWD option, power is supplied to all four wheels
automatically with no need to shift between two-wheel drive and
four-wheel drive. If your vehicle is equipped with the AdvanceTrac
stability enhancement feature, you can change AWD modes, if desired,
by selecting AWD options through the message center.
For the lubricant specification and refill capacity of the AWD transfer
case refer to Maintenance and specifications chapter.
If your vehicle is equipped with AWD, a spare tire of a different
diameter than the road tires should never be used. Such a tire
could make the vehicle difficult to control as well as result in damage
to driveline components.
Utility and four-wheel drive vehicles are not designed for
cornering at speeds as high as passenger cars any more than
low-slung sports cars are designed to perform satisfactorily under
off-road conditions. Avoid sharp turns or abrupt maneuvers in these
vehicles.
The following sections, Normal operation, Autolock operation and
Disabling AWD, apply only to vehicles which allow the driver to change
AWD modes through the message center.
Normal operation (vehicles equipped with AdvanceTrac
During normal operation:
• the AWD system is in AWD AUTO mode (AWD LOCKED will
illuminate in the message center for four seconds when you first start
your vehicle). The AWD LOCKED indicator in the instrument cluster
will also come on.
• AWD AUTO mode can be overridden by pressing SETUP in the
message center. When you first press SETUP, AWD <AUTO> will be
displayed, then if you press RESET within four seconds of pressing
SETUP, AWD <LOCKED> will be displayed. AWD <LOCKED> provides
power to all four wheels constantly which allows you to operate your
vehicle in severe winter or off-road conditions such as deep snow, ice
or shallow sand. It is not recommended that you use AWD <LOCKED>
on dry pavement.

Page 225:
• AWD <LOCKED> can be cancelled by pressing RESET in the message
center. (The AWD LOCKED display in the message center will then
turn off and the display will return to AWD <AUTO> for four seconds
when the shift is complete.)
Autolock operation (vehicles equipped with AdvanceTrac
If the AWD system begins to overheat, the system will place itself in the
Autolock mode:
• the AWD LOCKED indicator light will illuminate in the instrument
cluster and AWD DISABLED <LOCKED> will be displayed in the
message center.
• AWD LOCKED will be displayed in the message center for four
seconds and a warning chime will sound. This condition may clear
without any action being taken by the driver.
• the AWD LOCKED indicator light in the instrument cluster will turn
off when the AWD system cools down.
• When the system is sufficiently cooled down, AWD AUTO RESTORED
will appear in the message center for four seconds and a warning
chime will sound.
Disabling AWD (vehicles equipped with AdvanceTrac
When a problem is detected in the AWD system:
• the AWD LOCKED indicator light in the instrument cluster will flash
eight times every two minutes in the message center.
• The message center will then display AWD DISABLED for four
seconds, then SEE OWNER'S MANUAL. A warning chime will also
sound. The warning displays and chime will continue until RESET is
pressed (which will clear the message from the display).
• AWD LOCKED can still be engaged by pressing SETUP (the message
center will display AWD <DISABLED> LOCKED), then pressing
RESET. The AWD LOCKED indicator light will illuminate in the
instrument cluster and the message center will display AWD
DISABLED <LOCKED>.
• To disable AWD, press RESET. The system will go back to AWD AUTO
mode momentarily, then the AWD LOCKED indicator light will flash in
the instrument cluster eight times every two minutes. The display will
then show AWD <DISABLED> LOCKED for four seconds and then
turn off.

Page 226:
• If a serious problem occurs with the AWD system, the AWD LOCKED
indicator light in the instrument cluster will flash 10 times every two
minutes. The message center will also display CHECK AWD and a
warning chime will sound. You can press SETUP to check the status of
the AWD system (which will display AWD <DISABLED> LOCKED),
but the AWD system will be disabled until the system is serviced.
Driving off-road with truck and utility vehicles
AWD vehicles are specially equipped for driving on sand, snow, mud and
rough terrain and have operating characteristics that are somewhat
different from conventional vehicles, both on and off the road.
When driving at slow speeds off-road under high outside temperatures,
use 1 (First) gear when possible. 1 (First) gear operation will maximize
the engine and transmission cooling capability.
Under severe operating conditions, the A/C may cycle on and off to
protect overheating of the engine.

well the RPO tag on the car shows all options.
read that. and see if you have 4wd/or AWD.

i cant guess that.

keys in pocket , tires on ground? in park ( and what is the lever at , it the 4wd shifter? )
i have a jeep true part time 4wd, and (3 of them )
and one has locking hubs.
i the hubs are free. and 4wd lever is in 2H,
i can in fact, turn the axle (its hard to turn but does.)
and the transfer case slips inside,
other my 04 has and electric motor that creates pressure.
key off, no pressure, therefore the hubs are not locked.
if they are, they are BAD>
if i have LSD axles, I CAN NOT, (if either hub is locked)
my open axles are not LSD.
next AWD, i dont have AWD,
but it is a full time system. with a center diff.
and i think most (gee ,there are many types) you can not turn
the axle. due to it wanting to turn the rear axle.
some AWD can be disengaged, RTM on yours.
my newest jeep 07 has a read drive shaft , break away clutch.
that slips when you leave 4wd engaged on pavement (bad driver)
but not my 04. (2 )

this is a generic answer. i you post the 4wd/awd option question
we can go to as deep as you like.

Awd is on demand 4wd, better fuel economy
4wd high is locked in high range
4wd low is lock in low range

It's either the sensor on the top of the transfer case, or the one on the front diff. Look here, scroll down to about the third post.

http://msport97.proboards.com/index.cgi?board=faq&action=display&thread=6258