4WD LIGHTS flashing while driving

when I'm driving down the autobahn my 4 WD and 4WD Low lights start flashing on my 89 explorer they flash 6 times then stop. after going 5-10 Miles they do it again. anyone have this problem or know what it is trying to tell me if it is a system warning?

thanks

Reply to
eurrider
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You need to have the codes pulled

Possible xfer case speed sensors and/ or 4x4 motor

Reply to
JohanB

Reply to
eurrider via CarKB.com

The flashing is reporting that the GEM computer which controls the Control Trac 4WD system (as well as other things) has detected a problem, and likely in your situation it is one of the speed sensors mounted in the transfer case. The way the system automatically increases power to the front wheels is by monitoring the relative speeds of the front and rear driveshafts. If the rear is turning faster than the front, it must be slipping, so the transfer case clutch engagement period (it is pulsed) is increased in increments until the speed of the rear is equal or less than the front. If it gets to full engagement (locked transfer case, like selecting 4WD-Hi) and this speed difference seems to remain, the GEM realizes this cannot be, so it shuts off the 4WD and flashes the lights inside.

These are Hall-effect sensors that read the passing of gear teeth to send pulses to the computer and many have found that just cleaning them helps, probably because metal bits get caught up in the teeth or on the sensor face over time. Connectors should also be checked, or the sensors can just be replaced. As I recall, there are 3 in the case, but only 2 have to do with the 4WD function...I think the other was for vehicle speed.

Reply to
Vic Klein

Thanks VIC Will pull and clean them this weekend. let you know on Tuesday how it worked.

Have a great holiday weekend.

Mac

Vic Kle>The flashing is reporting that the GEM computer which controls the Control

Reply to
eurrider via CarKB.com

Further to your problem above I have a similar problem with lights and a smart GEM Looking allover I found that if removed the battery power and reconnected in 1 hour reset GEM and its fine except, If I move to Low 4WD it stays in this mode - to fix remove batt lead reset all OK. Any body help. Is this to do with the cam, motor, dirt , sensors etc

Reply to
edrickhard

i tried the cleaning of the sensors and was great guns until today. now at low speeds it try's to shift into 4WD LOW. will try the battery post and see if that reset it.

thanks for the help,

snipped-for-privacy@aol.com wrote:

Reply to
eurrider via CarKB.com

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