While driving my 2008 Land Cruiser in 4 hi, the 4 lo light illuminates and there is an audible alarm, but the 4 lo is not engaged. The check engine light comes on at the same time as well. It appears as if the 4 lo indicator is malfunctioning. Is there any reason for this occuring?

what speed are you driving at, in 4wd ? before it does this ?

I think these actuators depend on vaccuum, check that all the hoses are in place and intact, could also be the vaccuum pump.

On these issue, there are few solved help links for troubleshooting the issue easily.-------

Click the link below: ---

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

-----------

4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

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

Car will not go into 4WD high or 4WD low?

http://schematicsdiagram.blogspot.com/2011/12/car-will-not-go-into-4wd-high-or-4wd.html

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

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

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

4 wheel drive system will not disengage?

http://technoanswers.blogspot.com/2012/01/4-wheel-drive-system-will-not-disengage.html

----------

4WD light is flashing and beeping? NO 4WD high?

http://schematicsdiagram.blogspot.in/2012/02/4wd-light-is-flashing-and-beeping-no.html

----------

2002 Jeep Wrangler: 4WD Idiot Light is ON?

http://technoanswers.blogspot.in/2012/06/2002-jeep-wrangler-4wd-idiot-light-is.html

----------

Traction control switch will not engage on 4WD High or Low

http://whoisbyme.blogspot.com/2012/10/traction-control-switch-will-not-engage.html

-----------

4WD light flashing and 4WD will engage after few minutes

http://repairhelpcenter.blogspot.com/2012/10/4wd-light-flashing-and-4wd-will-engage.html

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

2008 Toyota Tundra: 4x4 Wheel Drive Light is Flashing?

http://technoanswers.blogspot.in/2012/05/2008-toyota-tundra-4x4-wheel-drive.html

----------

4x4 front differential will not engage the axle on ford?

http://technoanswers.blogspot.in/2012/02/4x4-front-differential-will-not-engage.html

-------

4x4 will not engage on Ford F150?

http://technoanswers.blogspot.in/2012/02/4x4-will-not-engage-on-ford-f150.html

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

Dodge Ram 4x4 light keeps flashing

4X4 LOW LIGHT IS FLASHING ON DASH

http://technoanswers.blogspot.in/2012/09/dodge-ram-4x4-light-keeps-flashing.html

----------

Ford 4x4 front wheels will not engage?

http://technoanswers.blogspot.in/2012/02/ford-4x4-front-wheels-will-not-engage.html

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

These details will help.

Thanks.

use it in slippery or adverse conditions, you won't need it for a light dusting but when things gt slippery put it in 4 and get the extra traction, keeps the front end from drifting and the vack end from sliding out, you will notice a drop in fuel consumption when engaged

The hi/lo is a function of the 4 wheel drive on the vehicle. The hi ratio would be used when negotiating sand or mud for instance and the lo for steep inclines where more power is needed. This is like having a gear with better pulling ability than first gear. You will find driving in 2nd gear lo will give you the same speed as 1st gear high.
Do not engage the four wheel drive system when driving on hard surfaces ie tarmac or concrete. Use it only on surfaces where additional traction may be needed. It is a good idea to use the 4 wheel drive system at least once a month in order to lubricate those parts of the 4 wheel drive system that would otherwise be "dormant" when in 2 wheel drive.
If you have diff lock funtion on the vehicle it would be a good to idea to engege this as well but once again only on a soft surface. The reason being that the centre diff lock tends to bind and stay engaged due to it not being properly lubricated.
If it does bind(dash indicator stays lit) find a patch of grass or sand, engage reverse and drive a couple feet. If this does not disengage the lock turn the steering fully left or right and drive in a circle. This should then disengage the difflock.

First thing to do is engage your front hubs. Gold colored locking mechanism in the center of the hub with arrows reading "free" and "engage" rotate the mechanism towards the engage until it stops. do this on both front hubs. Then start and let engine idle, depress the clutch and shift the short (right) shift lever to the "High" position, then shift transmission lever into 1st gear and then you will be in 4 wheel drive.

this sounds like the the indicator for the four wheel drive system make sur it is set for 2wd not 4 LO

check the parking brake switch if it is engaging and disengaging when you pull the the parking brake.

best u use mobil one synthetic motor oil