New lesson on "simple repair"

[Pistolero]

My 4Runner rear hatch latch is electrically closed, something I never understood the need for, but there it is.

Today, picking up some cable from a friend, couldn't get the door to close, it would electrically
cycle, but still be unlatched. After it opening while driving on his gravel road three times, I
was worried about getting home.

Finally it held, and when I got home it came right apart. It had done this a couple of times at
Oshkosh, but hasn't given trouble since then, until now.
Pulled the overly complex latch assembly, cleaned out some dirt, lubed it, cycled the motor
as per shop manual. Checked that limit switch was working correctly, and latch position
rotary switch was working correctly, too. Reinstalled and......dead as a hammer. Nothing.
Not even trying. Pulled it and checked again, running perfectly on the bench, hot wired.
Reinstall, nothing, won't run. Pull apart, start checking wire continuity, and looking closely
at the connector.
Connector looked perfect, wires not broken........What the heck? Mechanism works smoothly
on the bench, won't even power up on the car.
Looking at the net for a wiring diagram, couldn't find one. Did a check on "fixing 4Runner
rear latch"... ran across a youtube video, but it was only a couple of minutes, seemed way
short, but I looked at it.

The guy, apparently a commercial shop, said "We had installed a backup camera on this
4Runner, and then the latch wouldn't work. We had disconnected this plug (pointing to the
latch plug that I had to pull to remove the latch) and after we put it back it wouldn't cycle the
latch. So we pulled these three plugs (pointing to the controller box inside the hatch, with
three plugs about 20,20 and 40 pins!) and then disconnected the battery for about 20 seconds,
reconnect the plugs, then the battery and it all worked fine."

Damn. Reboot the darned thing. I went out and unplugged the door controller box, pulled
the ground on the battery for 30 sec, replugged the controller, reconnected the battery, and it
worked perfectly

Good grief. A pull cable would be fine, really. Too many computers in a car, IMO.

But, keep that in mind, a simple cleaning and lube of something as lowly as a door latch can require
a system reboot to get it work.

You can learn something every day, if you'll pay attention.

Bill

 

[Ben]

Bill,

My friend had a 52 Plymouth, He and I kept that car going for years. If you had a screw driver, a pair of pliers and an adjustable wrench , you could do just about everything to that car less a total engine rebuild.

When you raised the hood on that car, he and I could climb in and work on that engine. You could easily get your hands on anything on that engine.

Not today ! !

Ben

 

[Pistolero]

Ben,
When I was a teen, a friend had a '50 Plymouth, cut down from the windshield back,
plywood bed behind the front bench seat, real trunk on the back, against the front
seat back, for a trunk, of course. You hit one close to my heart, too.

That was about '66 thru mid 70s. We hunted from it, just cruised around the dirt roads, and
enjoyed that old beast. When the frt crossmember rusted out, we found another in a
junkyard, cut it out, jacketed up the old one, cut out the crossmember and welded in
the new frame piece. Put the engine mounts and reattached the A-frames and such
and drove it for more years.
Simple, reliable flathead straight six. Probably had about 10 wires, total in that car.

Bill

 

[Brad]

This is why God created people like Ian.
I have money, he has skills, we trade.

My hands stay clean, he gets to feed his family. We all win!

 

[Pistolero]

I like the challenge, and am cheap, plus it offends my sensibilities to replace
a part that can be cleaned, lubed and reused. Just something wrong with that
and no paid mechanic will do that today, install a new assembly if the old one "doesn't work",
regardless of why.
I find that wasteful and won't play.

Bill

 

[fiver]

if it was mine it would have got a hasp and a padlock.
I'm over the electronics on new cars.
I'm pretty positive my dodge weighs 5600 lbs because it has 3500 lbs of wire running through it.

 

[Pistolero]

Brad,
Think about throwing away your revolver when it gets dirty. Just clean and
lube, and go again. The only thing actually wrong here was some road dirt and old
grease.

Unfortunately you have to get permission from the rear door controller computer
to play with "his latch" .....

Bill

 

[Intheshop]

I bought wifey an early 4 runner.Back when they had solid Fr axles.Bought used before they got all "upscale".By the time her and the kids got done wiping buggers on it and decided to sell.....well dang,it's worth more than I paid for it.

Reboot...first line of defense.Glad you found the fix.BW

 

[S Mac]

I sometimes find a reboot is what is needed on modules on todays Autos. Likely the module sensed excessive resistance in the latch and shut down to protect itself.

By the way Bill, we are not all part changers only.

Steve Mc

 

[Brad]

Bill, it isn't so much a matter of throw away vs clean and repair. To me it is more a matter of a complete lack of interest in doing that sort of work. Cars hold no interest for me.
Now a revolver, that is another matter. I will do all I can with those. Tear apart, learn how they work, repair.
All a matter of desire to me.

 

[Rick]

Now a revolver, that is another matter. I will do all I can with those. Tear apart, learn how they work, repair.

Hhmmm . . . There is hope for you yet. Now if we could just get you shooting one.
.

 

[oscarflytyer]

Bill,

My friend had a 52 Plymouth, He and I kept that car going for years. If you had a screw driver, a pair of pliers and an adjustable wrench , you could do just about everything to that car less a total engine rebuild.

When you raised the hood on that car, he and I could climb in and work on that engine. You could easily get your hands on anything on that engine.

Not today ! !

Ben

Man I miss cars and trucks like that!

 

[Pistolero]

Steve,

Good to know that there are still folks who would do more than - "latch doesn't work right, replace it with a new one"
which costs about $220 in your hand, by the way. So at least an hour labor or more on top of that. I figure that most folks
with this drive into a dealer and drive out about $350-400 poorer.

Even looking at the shop manual, all responses to any issues were "replace latch assembly", right there in black
and white the Toyota factory manual says to do it this way. Nowhere does it say, "clean and lube" and it does
not mention the reboot, either.

All it needed was a clean and lube, as I expected. Just didn't expect to need to make sure that the computer was
cool with me fooling with "it's latch". Still seems massive complexity overkill. The electric stuff is grafted on top of the
original mechanical latch, the arms for the pull cable are still there. There is a plastic panel that you can pop open as an
emergency unlatch if the electric fails. You reach in and pull the handle with a cable end attach on the end of it.
Probably in other parts of the world the latch is purely mechanical, just leave off the motor and switches, put in a
pull cable to a mechanical handle on the back door instead of a pushbutton.

Bill

 

[Ian]

Bill, hate to break it to ya but power door locks, power windows, auto hatches, and releases haven't worked on straight 12V +/- in two decades. With all the feedback wiring the bundle of copper to the BCM would be as big as your leg. What to do? Why "network it" of course! Multiplex signalling on a PCI or CAN bus allows just a few wires to do everything.....but you gotta have a decoder thingamajigyy for unscrambing the ones and zeros. The switches just put a request out on the network, it goes like this when you press that little switch:

"Hey everybody, driver wants the liftgate flipper glass open, so let's go 'round the Horn:
Instrument cluster: Check. Vehicle speed zero. Engine off. Flipper glass position 'closed'. Proceed with 'open' command.
Transmission Control Module: Vehicle in P/N. Vehicle speed zero. Proceed with command.
Central Timer Module: Roger, roger, all prerequisites met, sending flipper glass open signal.
Rear Door Control Module: YAWWWWnn....Ok, sending 20 ms pulses of filtered battery voltage to solenoid.
Flipper Glass Position Switch: HEY EVERYBODY: The flipper glass is open!!!!!!
ECM: Roger that. Engine start disabled.
Instrument Cluster: Roger that FGPS, liftgate ajar lamp illumination signal sent."

And so on, or some scenario like that, with the ignition key in your pocket. Actually, there's probably a lot more going on back and forth between the modules than that on the network for one little switchy press. Now, if any of the modules get their ones and zeros scrambled up, no battery voltage for you, Mr. flipper glass actuator!

The multiplexed CAN bus signal works by frequency modulated signals on different voltage bandwidths between 1 and 12. volts, so not all computers talk to each other, it's sort of a hierarchy. For example the Driver's Door module can't talk directly to the ECM, it's signals are censored and fed to other modules only as required by some sort of body control module. It's really very simple for anyone with exposure to the basics of computer networking, proxy servers, and programming. In fact, automotive computerized control systems are frustratingly PRIMITIVE and CRUDE. There's more technology in my flip phone than in any car. I expect one day our cars won't have their own computers at all, they'll just run off something like an iPhone and be permalinked to the Cloud grid through secured, .gov monitored satellite channels.

 

[Pistolero]

Yikes! Thanks for the update, good explanation. I was aware of CAN bus, and such but not really aware that all the smaller stuff like
door latches and windows were linked in.... amazing. I was thinking more like yaw sensors,
antiskid braking, traction control, stability control, that sort of stuff.

Still seems like swatting flies with a 12 gauge. It works, but REALLY?

So, now I learned on two days in a row. I will now come to expect that any simple clean and lube job that drops something
off it's connection will require a reboot.

I verified this today. I had put it back together and it worked, but I had left off the plastic cover and weatherstripping
during troubleshooting, so was going to have to pull it out to put on the cover and stuff. So, when it was working perfectly,
and like you say, Ian, key in my pocket, I opened the hatch. Unplugged the connector to the latch, waited 10 sec (probably
not necessary) and plugged it back in. Closed hatch.....no latch, dead. Pull battery, wait 30 sec, reconnect, back in business.
Just wanted to verify that just a short disconnect, with nothing else, it is dead until a reboot.

OK, well....cars is complicated! Still learning.

This relates to a friend who worked as a VW mechanic for his whole life. He told me that a current model Jetta, and this
was 10 years ago, had, IIRC, 45 different CPUs......my comment was that my '66 VW didn't have 45 different CIRCUITS
in the entire electrical system, a snappy come back. I happened to stop and count one day after that pulling out an
old VW shop manual, looking at wiring diagram. Way less than 45 circuits, but I forget now the exact count.

Bill

 

[Hawk]

My brother is an old time auto mechanic with certifications in everything you can have.
He said to buy the extended warranty on my new Chevy LTZ Z71.
He said it probably has 17 onboard computers and any one that goes out would probably be upwards of $2,000.00 to replace and reprogram.
Talked to the service manager at the dealership and he said even the shocks are computer controlled!
I had a '68 Camaro SS when I was in high school and we jacked up the engine, tranny and everything else on that car.
What a simpler time that was.

My brother said he has a customer that brings in a corvette for state inspection. The owner spends 15 minutes on a computer hooked to the car and says "now it will pass inspection".
It get inspected and the owner fiddles on the computer another 15 minutes and has the car back up to about 800 horse power.
Bro says the guy bought the car new and spent another $30,000 on performance parts.
What a world! I remember when a fuel block, the proper carburetor, headers and a full cam was nearly all you needed.

 

[Pistolero]

Yes, definite complexity.

A few years back we were hunting mulies in SW Wyomning. Riding in a friend's
Suburban. We had to go into 4WD low range for a section of deep mud, way out in the
middle of nowhere. Got through it OK, then he punched the button to go back to 4WD
high......nothing. Top speed is now about 25 mph and we are a LONG way from a
hard road, much less a service place, road is OK for 40 or more. Easy 80 miles to a town, may
be more.

So the front seat guy grabs the owner's manual as we drive along, driver punching the
buttons to no avail. After about 8-10 minutes the front passenger starts laughing
out loud, and says "you're not going to believe me." After he laughs some more, reading
more, he says, OK, stop the truck.... then to our very skeptical looks, we are SURE he
is just screwing with us, the driver goes through a set of ridiculous gyrations, IIRC, opening
the driver's door twice, in and out of gear, then park, then reverse, then open the passenger door,
and .....I forget, maybe turn on the dome light twice and lots of silly unrelated stuff, key on and
off, all in a specific order.

Finally power down the truck. Power back on, punch "2WD High" and click, all is normal.
We laughed our head off for 20 minutes about that. This was the official, book, emergency
procedure for getting the truck to pop out of 4WD low if it refused.

Too many computers.

Bill

 

[Rick]

Fascinating. A couple of years ago I took my truck to the dealer to get a battery, used the dealer because they were the only ones in town that carried Interstate Batteries. When I got home I discovered the left headlight out, thinking they knocked off the plug or something I went back & they replaced the headlight, my dime. Headlight still didn't work & they hooked up the diagnostic puter under the dash, headlight working again but drove home with door locks not working. Back to the dealer and once again hook up the diagnostic puter and they tell me the trucks puter control box is out and they will need to order one. $300 and my dime again. Box comes in and they install it, door locks still don't work. The service writer says that their diagnostic puter turned out to be malfunctioning so they couldn't reset the door locks but if I will come back in a couple of days they will have a new one. Me says then give me my $300 back because if your diagnostic puter isn't working I didn't need the $300 part your diagnostic puter said I needed. The guy says oh no we checked out your system by hand not the diagnostic puter. BULL me says. No refund though. I know the service manager, his MIL is my next door neighbor. I went back to the dealer four more times to try to talk with him but seems he's always out, just never in to talk with customers. Not even when he's next door will he talk with me now.
/.

 

[Pistolero]

Rick,
Sounds like a dealer to avoid.

OK - one more funny story and I am done on this topic.

I need to add another key fob to the car, bought it on eBay for cheap, got the info on how to get the
car to talk to the fob. THIS IS HILARIOUS, but entirely true.

Do these steps - exactly.

Driver's door open, key removed from ignition switch.
Within 5 seconds:
Insert and remove the key from the ignition switch twice.
Within 40 seconds:
Close and open driver's door twice.
Insert and remove the key from the ignition switch.
Within 40 seconds:
Close and open driver's door twice.
Insert the key into the ignition switch and close the driver's door.

Switch ignition ON and OFF once to program a remote transmitter code while
retaining the original codes or twice to program a remote transmitter code
whilst erasing the original codes. Three times to check how many remote
transmitters are currently registered or five times to erase all registered codes.

Remove key from ignition switch:
System should now lock and unlock vehicle once, twice or five times
depending which mode has been selected. One to four times, slowly, to
indicate number of remote transmitters registered.
Within 40 seconds:
Press and hold LOCK and UNLOCK buttons simultaneously for 1.5 seconds -
Within 3 seconds:
Press LOCK button.
System should now lock and unlock vehicle once to confirm registration,
twice to indicate registration has failed.
Within 40 seconds:
Repeat button procedure to program remaining remote transmitters.

NOTE: To exit programming mode: Open driver's door.

NOTE: A maximum of 4 remote transmitters can be programmed.


It may take a few tries and the timing must be very accurate to work but with a little patience it works.

No lie, this is for real. I had to have someone read it to me to hit the time marks.

Bill

 

[freebullet]

O man I was guna mention the " bcm", but Ian beat me toit.

They wake up & go to sleep....well they should anyhow. It would take 5 pages to describe what I've been through to fix our express from a host of issues. You ain't had fun till you've delved in to that poo poo.

It was so infuriating I bought another 1997 afterward. Anything after 98 is getting purty retarded far as trucks, that ship sailed awhile before on cars. Once you get past 2000 they are piles of s--- straight from the factory imo. No way around it.

Plain and simple needless overcomplication. Today we need a 350+$ computer to do what $40 in relays has done since the 1960's.

Rick,
I'm sorry that happened to ya. After dealing with a couple dealers I can say that I will not ever go to another.

A good plan for anyone disconnecting electrical components or batteries on 98+ vehicles is to disconnect the battery. When done reconnect battery with all doors closed, the key removed from the ignition & car completely, fire up let run for 15-30min, go drive same then park & test all those functions after 30 min. Sometimes the computers simply don't reset properly otherwise. Can take 2-3 resets on some vehicles.

I've got the 97 2500 torn apart for refurbishing with no regrets. Even when I pay for it done, older is cheaper and often easier. The truck & refurbishing is cheap enough that gas to feed the big block is irrelevant compared to the cost of new. My newest vehicle always cost us the most money & headaches.