Remote Window Roll Down Stopped Working (1 Viewer)

[P Hill Up]

06 lx470. Had about 2 years. Really hoping it isn’t a master window control module b/c those are expensive.

Until about a year ago window roll down by holding unlock on key fob. worked just fine. Click unlock twice and hold, after a few seconds long beep from the truck and everything starts coming down.

A year ago - front driver’s side window was slow, so i sprayed white lithium grease into window as recommended on some threads. It worked to speed up windows for a few days then got tacky and slow again. So, i sprayed more. A lot more. This caused the door locks to go nuts locking randomly and/or refusing to unlock. At the same time, the auto up feature on the driver’s window stopped working. Would go up and then act like it detected a pinch and roll down half way.

Passenger window rolled up/down just fine, as did the back windows. I assumed i messed something up by getting lithium grease into it, so i made an appointment with the Lexus dealership. Before the appointed time, the locking problems went away. Window problem remained, and i noticed the roll down with the key fob function wouldn’t work. Dealer couldn’t reintroduce the locking problem, so they just said i must need a new master door lock and master window control module. I just lived w/ the minor inconvenience.

Yesterday, i switched the window run hoping the pinch detector may have been causing a window fault that prevented the roll down with fob function. Didn’t work. Auto up function also wasn’t fixed + a new problem developed. Previously, if i help up the auto up it would stay up. It was only if clicked up auto up and let go, then it would roll back down after it reached the top. After replacing the window run, now even if i held the auto up window toggle all the way up it would now roll down as soon as i let the switch go. Only if i feathered the window switch to go up manually would it stay up. Frustrating to introduce a new fault, but still livable.

Today i took apart the door again and reset the window motor after disconnecting it from the gear. A pain, but it fixed the auto up feature finally. Windows go up and stay up. But, still the key fob roll down doesn’t work.

Anyone have any ideas on what the problem could be? In the summer the fob roll down feature is very nice and i’d like to regain as long as it’s not a few thousand dollars to do so.

Sorry for the longwindedness, but figured more detailed initial post might be more useful than short statement and a bunch of follow-up “i already tried that” replies. Thanks for any ideas.

 

[Malleus]

Since your problem appears to be related to the keyfob operation of the window, I'd focus my effort on the body ECU, rather than the window power switch or motor.

There are three (relatively) easy checks to make:
1) the White wire with the Black tracer (W/B) is the ground wire.
2) the Blue wire with the White tracer (B/W) and
3) the Black wire both connect the body ECU to the master switch.

Disconnect the switch (in the door) from the harness and inspect the connector housing terminals 2, 3, 7 & 9. This is what the harness connector looks like:

Here's the switch layout:

Check the appearance of the terminals, all of them, but especially these four, for any sign of corrosion. Any contamination (not corrosion of the terminals) in the housing can be removed with CRC plastic safe QD Cleaner. Corrosion on the terminals themselves is tougher to treat. Deoxit may clean them, or you may have to depin the housing and rub them with crocus cloth (or some similar very fine sanding cloth).

If these appear to be OK, check the other end of the harness, at the body ECU. The EWD says the connections are in the B7, B8 & B9 connectors, but don't indicate which connector housing has which wire. PITA, but it'll be obvious; there won't be two wires of the same color in two different connector housings next to each other.

The numbers at the wire connections with the switch or ECU are the terminal numbers in the connector housing illustration.

For simplicity's sake, I'd assume the junctions between the switch and ECU are OK. There is no reason to make your life any more difficult than it already is.

The service manual is suprisingly unhelpful on the operation of the keyfob. The CANBus (mulitplex communication) system is very sensitive to wiring faults, like loose grounds and can be very hard to troubleshoot. These are the easy (DOH!) things to check; I'm not saying it's likely this is the problem, bu thtese are the areas you want to cross off the checklist first, before you go up to your elbows in troubleshooting.

 

[Malleus]

If you're not familiar with Toyota EWDs, I'd download BOTH the 2006 and 2005 Land Cruiser EWDs. Starting in 2006, Toyota redesigned the layout of the Land Cruiser EWD for "better" screen viewing, using TIS at the dealerships. I'd argue this wasn't great for them, and it's really bad for us, working at home or in a small shop.

All of the explanatory notes from the front of the EWD were deleted (they're in the 2005 version), making the documentation difficult to use for someone unfamiliar with previous issues of the EWD.

The information on pages 2-19 is necessary (IMO) to effectively use the EWD, especially pages 14-16, illustrating how to depin connector housings. This information is also in the Wiring Harness Repair Manual, in the Resources forum, Land Cruiser, 100 section (I'd get that, too). FWIW, the SST to depin the terminals in the connector housing is very nearly the same as the 'next to smallest' screwdriver in my Stanley "Precision" screwdriver set.

 

[Malleus]

If the "simple" wiring faults don't appear to be the root cause (that is to say, there are no obvious problems with the wiring, at least at the switch or body ECU), I'd try the Diagnostic section of the 2005 service manual (RM1147U), (the 2006 manual may have this information, but I've given up trying to find anything in there). The file is searchable; CTRL+F opens the search window, type "power window" and keep hitting Enter until you get to the DTC section.

I think the test procedure starts on page DI-1098; check this to make sure. The procedure is described using the Toyota intelligent tester, which you won't have unless you work at a dealership. Techstream may do the same thing; I haven't tried it.

The service manual seems to indicate the FM transmit/receive functions related to the keyfob are contained in the Theft Deterrent System (TDS) ECU. I mention this for information only, I've never tried to troubleshoot the keyfob system. My son's 2000 LX470 has flaky door locks and I'm hoping it's the motors so that I don't have to educate myself on Toyota's wireless communication system integration.

I hope this helps in some way.

 

[P Hill Up]

Thanks for the advice. I’ll check the wires accessible from the door and report back.