4x4 lights flashing

[wolfdadg]

my 98 explorer's 4x4 light ( both High and Low ) are flashing ( usually 6 times ) then they stop for a little while and then cycle through again - both transfer cases are full of oil and I was wondering if anyone would have any Idea why. Any help is greatly appreciated.

 

[NHale623]

What do you mean by "both transfer cases are full of oil"? How many do you have?

 

[gijoecam]

The blinking lights mean that the system has detected a fault, stored a trouble code in the GEM, and deactivated the 4wd system. The *proper* fix is to have the codes scanned (AutoZone can't read GEM codes), and troubleshoot from there.

Now, that being said, about half the time on these boards, the cause is the rear axle speed sensor taking a dive. It's about a $15 part and is exposed to the elements and takes a fair amount of abuse. Crawl under, check for any obvious signs of damage (torn wires, corroded connectors/pins, etc.) and if it all looks good, try replacing it. It really could be that simple. Worst case, that doesn't fix it, and you still need to go to the stealership. It's only another $15 on top of it.

Good luck!

 

[Steeda90GT]

Before you do any of that, unplug the negative terminal of your battery for 20 min and reconnect. 9/10 this fixes it as the computer needs to be reset.

 

[gijoecam]

Before you do any of that, unplug the negative terminal of your battery for 20 min and reconnect. 9/10 this fixes it as the computer needs to be reset.

Common misconception. Disconnecting the battery will not correct a wiring issue or erroneous sensor reading, which is what the system is detecting in the first place (as evidence by the blinking lights).

 

[wolfdadg]

sorry my bad -- I meant to say both the front and back pumpkins ( gear boxes ) are full of oil - but - thanks everyone for the starting point. I will start there and see what happens.

 

[Steeda90GT]

Common misconception. Disconnecting the battery will not correct a wiring issue or erroneous sensor reading, which is what the system is detecting in the first place (as evidence by the blinking lights).

How do you know he has a wiring issue/bad sensor though? Disconnecting the battery is the easiest thing to try first. Only takes 60 seconds. Let it sit for 20 min, then reconnect.

If he's still getting the blinking lights then proceed to diagnose.

 

[gijoecam]

How do you know he has a wiring issue/bad sensor though?

Uuuh, because of the blinking lights. The 4wd lights will only blink if the system is currently detecting a problem. If the problem corrects itself (e.g. if a bad connector gets wiggled and makes contact again). The diagnostic cycle resets and repeats with every restart.

Disconnecting the battery is the easiest thing to try first. Only takes 60 seconds. Let it sit for 20 min, then reconnect.

If he's still getting the blinking lights then proceed to diagnose.

My point is that resetting the system won't correct any problem the system is currently detecting thereby causing the blinking lights. To do so is simply resetting a system that already resets itself with every restart. The lights *may* go out until the trouble is detected again, but it does nothing to either identify or correct that problem. There's nothing in that system that resetting the battery will fix.

It's just like resetting the CEL even though the diagnostics show a bad EVAP purge valve. Yes, resetting the ECU and clearing the DTCs will make the light go out, but only for a few drive cycles until the diagnostics check that parameter again and find the value out of spec. It doesn't fix the valve, just makes the light go out until the system checks it for a fault again.

 

[Steeda90GT]

Hmm funny, it worked for me when I did this last year (Summer of 2007) I noticed the lights blinking after a night of driving. So when I came home I looked it up on here and it seemed to be a typical problem. So far it's been a year (I drive my truck daily, many miles and multiple startups per day) and the blinking lights have not come back and my 4x4 has worked flawlessly since then.

I'm not saying this is a guarantee fix for the OP, but I would sure as hell try it before spending countless hours and $$$ on other solutions.

 

[gijoecam]

Hmm funny, it worked for me when I did this last year (Summer of 2007) I noticed the lights blinking after a night of driving. So when I came home I looked it up on here and it seemed to be a typical problem. So far it's been a year (I drive my truck daily, many miles and multiple startups per day) and the blinking lights have not come back and my 4x4 has worked flawlessly since then.

I'm not saying this is a guarantee fix for the OP, but I would sure as hell try it before spending countless hours and $$$ on other solutions.

Umm, did you try simply restarting the engine before you disconnected the battery? It would have had the same effect...

My 4wd lights have begun blinking on three separate occasions. The first time was 8 years ago after an hour on the freeway as I coasted down the off-ramp. I shut it off, restarted it, and it didn't do it again. The second time was about 6 months ago, on the freeway on my way to work. The code cleared itself after about 5 miles and everything went back to normal, no restart necessary. The third time was about three months ago. Hit some good slush piles in the winter getting off the freeway. The t-case was detecting slippage (as evidence by my lighted brown wire mod switch and the driveline bind-up in the parking lot) and after 10-15 seconds, it would deactivate the system and flash. I attempted multiple restarts to clear it, which worked until I started moving (again, pointing to a speed sensor issue). When I went out at lunchtime to investigate some more, it had healed itself. I suspect water intrusion into a connector, but I never found any evidence of such.

The system re-runs the diagnostic at startup. It does not store the trouble codes in its memory for retrieval. The control trac system only stores active trouble codes (unlike the PCM that stores them until they're cleared either by using a scanner or removing the battery power).

-Joe

 

[Steeda90GT]

The lights were blinking EVERYTIME I started the truck and would not go away until I disconnected the battery terminal... one week later. So for one week I had the blinking light dilemna..everytime I started the truck.

So far it's been a year and all is well.