2006 LX 470 stuck in Center Differential Lock for 3 weeks now (1 Viewer)

[Joel Brown]

I've been trying everything for 3 weeks. I called the dealer (nearest Lexus is 4 hours, nearest Toyota is 80 minutes away). Not sure if my wife had a water bottle fall on it or someone just switched to switch but backward figure 8's in the gravel, stop and start going forward, back ward, in neutral, the dash lights are lit (CDL, and VSC OFF) and it grabs on pavement with sharp turning (not doing that anymore). I may just have to haul to Lexus dealer.

I was hopeful that replacing a relay or giving power to the actuator (hooking up 12 V battery to correct terminals could get it out then I'll super glue the switch to prevent this from happening again.

Any thoughts on manually getting it out of center differential lock?

Any schematics to the wire harness to apply 12V to see if the actuator works or is the problem?

 

[geanes]

My CDL stuck once. I got the front left wheel up onto a rock and then the CDL disengaged. This was after having tried the figure 8s on gravel. You might try jacking up the front end and then hitting the CDL button.

 

[Joel Brown]

My CDL stuck once. I got the front left wheel up onto a rock and then the CDL disengaged. This was after having tried the figure 8s on gravel. You might try jacking up the front end and then hitting the CDL button.

I'll try that tonight.

 

[habakkuk007]

I got mine out by going uphill in reverse.

 

[Joel Brown]

Going strait uphill in reverse or turning?

Also is there a relay that gives power to the actuator or just straight power?

 

[knewstance]

Mine got stuck one time and I did all the same stuff. I ended up getting it out just by going faster in reverse for a longer distance. I had to step on it a bit when starting but it just popped right out.

 

[Spike555]

Exercise exercise exercise....this does not help you right now, but use the damn CDL button and the hi-lo shifter once a month. Make this a habit. Do it at the same time you check your tire pressure once a month. This keeps everything freed up and working so that that one time it does accidentally get used it does not stick.

 

[nakman]

What about putting the whole truck up on jack stands.. then you can turn the tires by hand, even with the transmission and/or t-case in neutral. And worst case, if it doesn't work you're already where you need to be to pull the front driveshaft off. Then you can drive it around without worry, also drive it to the repair shop when time allows. Tell the wife if it unlocks to just push the button again.

 

[Ayune]

Ok, so the fancy CDL system wiring diagram is below. It works like this:

Pushing in the CDL switch energizes the lower right relay to send battery power through the actuator motor to spin it in one direction. The lower left relay provides the motor’s ground path.

Releasing the CDL switch energizes the lower left relay and sends reversed-polarity battery power to the actuator motor so it spins in the other direction. The lower right relay provides the motor’s ground path.

The switch inside the actuator stops the motor from turning in either direction once it reaches its end-of-travel by deenergizing the active relay via disconnecting its ground.

The top left relay is controlled by the Low range detector switch, and does two things: it energizes the locking relay (lower right) and prevents the unlocking relay (lower right) from being energized. Hence the popular “Pin 7” mod.

It may be that your Low range detector switch is stuck closed? Cut Pin 7 and see if that helps: Center Differential Lock Mod (Pin 7 Mod)

 

[Spike555]

Ok, so the fancy CDL system wiring diagram is below. It works like this:

Pushing in the CDL switch energizes the lower right relay to send battery power through the actuator motor to spin it in one direction. The lower left relay provides the motor’s ground path.

Releasing the CDL switch energizes the lower left relay and sends reversed-polarity battery power to the actuator motor so it spins in the other direction. The lower right relay provides the motor’s ground path.

The switch inside the actuator stops the motor from turning in either direction once it reaches its end-of-travel by deenergizing the active relay via disconnecting its ground.

The top left relay is controlled by the Low range detector switch, and does two things: it energizes the locking relay (lower right) and prevents the unlocking relay (lower right) from being energized. Hence the popular “Pin 7” mod.

It may be that your Low range detector switch is stuck closed? Cut Pin 7 and see if that helps: Center Differential Lock Mod (Pin 7 Mod)

View attachment 1825662

So what if he swapped the two relays?
Could the release relay be bad?
Or do you think it's a ground issue?
My electrical knowledge let's me change a light bulb and that's about it, so I am asking to learn not to question.

 

[Ayune]

So what if he swapped the two relays?
Could the release relay be bad?
Or do you think it's a ground issue?
My electrical knowledge let's me change a light bulb and that's about it, so I am asking to learn not to question.

I’m thinking of the process of elimination and doing the easy stuff first. All the circuitry in the big blue box is inside the sealed plastic relay module behind the glove box so I don’t think it’s a serviceable item. The easiest test is to cut the friggin pin 7 and if things start working again then you know it was the L switch. If not, then at least you’ve eliminated a suspect, and you have the mod.

Top of the list would also be wiring harness inspection under the truck. Look for melted wires, etc.

Also, is the 20A “DIFF” fuse blown?

 

[Spike555]

I’m thinking of the process of elimination and doing the easy stuff first. All the circuitry in the big blue box is inside the sealed plastic relay module behind the glove box so I don’t think it’s a serviceable item. The easiest test is to cut the friggin pin 7 and if things start working again then you know it was the L switch. If not, then at least you’ve eliminated a suspect, and you have the mod.

Top of the list would also be wiring harness inspection under the truck. Look for melted wires, etc.

Also, is the 20A “DIFF” fuse blown?

If you cut the 7 pin how do you get it back? I assume you mean physically cut a circuit. Then do you resolder it? Or live with out it? Whats the repair from there? Or is there not one and life is fine because Toyota thought we didn't need whatever that was?

 

[habakkuk007]

Going strait uphill in reverse or turning?

The uphill was a short section of steeply elevated part of the parking lot - as soon as I climbed it in reverse, it was home free without turning.

Also is there a relay that gives power to the actuator or just straight power?

I have to leave this for the more knowledgeable folks here.

 

[Ayune]

If you cut the 7 pin how do you get it back? I assume you mean physically cut a circuit. Then do you resolder it? Or live with out it? Whats the repair from there? Or is there not one and life is fine because Toyota thought we didn't need whatever that was?

Agreed, cutting any OEM wire in a harness can be disconcerting. When cutting at a connector be sure to leave an inch or two of wire on the connector side in case you (or the next owner) wants to reconnect, and tape both ends to prevent shorts.

In the case of the “Pin 7 mod” it’s a matter of regaining the choice of when to engage the CDL. On 98-99’s Toyota wants to engage it automatically when the transfer case is shifted to Low, most likely to distribute the added torque equally to both front & rear diffs. The mod gives you full control to use Low range on surfaces with high traction without drivetrain windup. Not sure what year the OP’s vehicle is...

 

[Somebodyelse5]

Agreed, cutting any OEM wire in a harness can be disconcerting. When cutting at a connector be sure to leave an inch or two of wire on the connector side in case you (or the next owner) wants to reconnect, and tape both ends to prevent shorts.

In the case of the “Pin 7 mod” it’s a matter of regaining the choice of when to engage the CDL. Toyota wants to engage it automatically when the transfer case is shifted to Low, most likely to distribute the added torque equally to both front & rear diffs. Is there a situation where you’d want to be in Low and unlocked? Not sure, but it’s simply about freedom of choice with all the fun buttons.

Yes, there are lots of reasons you’d want the low, unlocked. Steep switch backs, like black bear pass...if you have to have the diff locked while you are in low (for engine braking) you get some nasty windup on the three point turns.