4th gen stuck in 4Lo. Help!!

[bobp315]

My brother dropped the truck off at a local mechanic during his lunch break. The mechanic said he'd check it out tomorrow. We're both pretty sure that the actuator is the culprit, but does anyone know if a separate actuator controls the activation of the center diff lock or if the same one controls both the center diff lock and the switch between high and low range? According to my brother the center diff lock hasn't been working for the past few months but the hi/low transition has been fine. Thanks to all of you who have replied. Y'all have given me some great info so far.

 

[4RBob]

My brother dropped the truck off at a local mechanic during his lunch break. The mechanic said he'd check it out tomorrow. We're both pretty sure that the actuator is the culprit, but does anyone know if a separate actuator controls the activation of the center diff lock or if the same one controls both the center diff lock and the switch between high and low range? According to my brother the center diff lock hasn't been working for the past few months but the hi/low transition has been fine. Thanks to all of you who have replied. Y'all have given me some great info so far.

There is a 4WD control module behind the glove box. My center diff would not lock and it turned out moisture had gotten to this and corroded it. Maybe this is the culprit for the center diff and possibly the 4Lo too.?...

 

[bobp315]

There is a 4WD control module behind the glove box. My center diff would not lock and it turned out moisture had gotten to this and corroded it. Maybe this is the culprit for the center diff and possibly the 4Lo too.?...

I had no idea that was there. Sounds like something I'll definitely have to check if the mechanic doesn't find anything. Thanks for the tip.

 

[4RBob]

here's what it looks like:

corrosion:

 

[bobp315]

Awesome. Thanks for the pictures. I should get a chance to check in out in a couple hours.

 

[Zinarac]

This might sound stupid, but it could be worth a shot. My friend's 2WD 4Runner was not shifting from 1st gear and thought it was the actuator. Someone suggested that he try a new battery and that did that trick.

It most likely is not the battery, but if it is it could save your brother a lot of money and hassle.

 

[bobp315]

Well here's what's happening. The mechanic charged my brother $100 to tell him that their diagnostic equiptment wasn't talking to the 4WD control module...so that must be what's wrong with it. Apparently the only way to fix it is to take it to a dealer and have them install and re-program a new one. His main concern is that instaling a new module won't fix the problem, and there's another underlying problem (e.g. 4x4 actuator) and he's out $5k before he knows it. Any recommendations on where to go from here? Thanks to all for your continued help. It's amazing how such seemingly small problems turn into huge ordeals.

 

[Tempsho]

It's amazing how such seemingly small problems turn into huge ordeals.

Especially electrical related problems. If the dealership will gaurantee that changing out the module will fix it or they will put the old one back and not charge you for that portion of the fix then I would say go for it. If they say that they will replace the module, and it doesn't fix it, and they charge you anyways, I would take it to another dealership.

 

[4RBob]

I think maybe he should bring it to a dealership and not tell them he has brought it anywhere else. Maybe tell them he has heard the 4WD control module has been a problem with other 4Runner's. Have them diagnose it, but ask them if the diagnostics will be rolled into the repair labor.

I wonder if you can just pull the 4wd control module out and see if you see any corrosion, etc.?...

 

[bobp315]

I wonder if you can just pull the 4wd control module out and see if you see any corrosion, etc.?...

Well, my brother gets off work in an hour, then we have to go pick the truck up from the mechanic. We're then taking the truck to my dad's house (he has an '06 4Runner) to try switching out the 4x4 control modules. If the truck comes out of 4Lo, then I guess we've found the problem. I've called the service manager at my Toyota dealer and he said that putting the module from my dad's truck into my brother's should work and should not cause any damage. He also said the 4x4 module is a $290 part that we should have no problem changing ourselves. Anyone see any reason that switching the modules would screw anything up? Apparently the modules are just plug-and-play and don't require any vehicle-specific programming. At least that's what I've been lead to believe by my dealer.

 

[4RBob]

I seem to remember (but it was 4 years ago) the dealer service dept telling me the computer had to be reprogrammed for the new 4wd module, but they could have been telling me a line of crap. I think they charged me an hour labor and about the same for the module as you were quoted.

I'd give it a try, maybe disconnect the battery when doing the switch over.

 

[chayos00]

Well, my brother gets off work in an hour, then we have to go pick the truck up from the mechanic. We're then taking the truck to my dad's house (he has an '06 4Runner) to try switching out the 4x4 control modules. If the truck comes out of 4Lo, then I guess we've found the problem. I've called the service manager at my Toyota dealer and he said that putting the module from my dad's truck into my brother's should work and should not cause any damage. He also said the 4x4 module is a $290 part that we should have no problem changing ourselves. Anyone see any reason that switching the modules would screw anything up? Apparently the modules are just plug-and-play and don't require any vehicle-specific programming. At least that's what I've been lead to believe by my dealer.

This here sounds like your best bet! If it works at least you can get it back to 2wd, then drive it with no problems.


To the others who have seen the "corrosion" on these modules, is there anything a person can do to prevent this corrosion? Like is it in the connector or electronics? If this seems to be happening to several people I'd like to do what I can now to prevent this $300 fix.

 

[bobp315]

I seem to remember (but it was 4 years ago) the dealer service dept telling me the computer had to be reprogrammed for the new 4wd module, but they could have been telling me a line of crap.

My dealer sure made it sound like that wasn't the case. I'm going to give it a try and see if I can't blow something up:ybrick: Will let y'all know how it goes

 

[bobp315]

Well, switched the 4x4 modules and nothing happened. My brother is outside right now hitting the actuator motor with a hammer to see if it will wake up but I doubt that's going to work. I guess it's time for him to suck it up and take it to a dealer. Ouch.

 

[chayos00]

Well, switched the 4x4 modules and nothing happened. My brother is outside right now hitting the actuator motor with a hammer to see if it will wake up but I doubt that's going to work. I guess it's time for him to suck it up and take it to a dealer. Ouch.

Bummer, hope beating it works!

 

[bobp315]

Yeah the hammer didn't work either. Who knows anymore...I give up.

 

[colombo]

Did you investigate your idea with 4WD switch?

 

[bobp315]

Did you investigate your idea with 4WD switch?

The switch on the dashboard is fine. That was determined by the original mechanic my brother brought it to. As far as the actuator under the truck goes, it's just too difficult to access. He's going to have to have the dealer see if that's the problem...and I think it at least has something to do with it.

 

[12guns]

What happened to your ride? What was the problem? Just curious. I'm not having the same problem but will be checking all my connections and greasing them to avoid such problems if possible. I miss the old manual hubs!

 

[guardiola]

Please can you update what happened to the vehicle and how the problem was resolved, I am having a similar problem as one of many issues I am facing right now.

@Chaz, many thanks for pointing this thread out