How to replace the "Main Body ECU Compu Network"

Hey Humble Leader,

The sensor(s) are in the door handle, so I think you're right... everything else works just fine! No need to worry about the Main Body ECU; that just presides over 26-27 other ecu's on the network. I'd just change the handle and hope for the best!!!

Please let me know how you made out when done! Best to you Humble Leader! rig

nice thanks! I will report back. going to try and tackle this myself maybe tomorrow or have the dealer take care of it on friday when I'm in for service anyway
 
Update to my update : the touch to lock isn’t working anymore and the touch to unlock is slow to work but it works. It’s a good three steamboats before the door handle recognizes my hand there and opens. Passenger and tailgate work fine

Was working fine for a while and now it’s acting up. As soon as the new handle was put in it was immediately fine for a while. Temperature hasn’t really changed the last couple days. No rain either or anything environmental that could cause this.

It’s unlikely a loose connector or a defective handle. It seems when the truck sits for a long period of time it stops working. The first time I noticed issues with the touch system was right before my car battery died. It hasn’t worked right since then on the drivers side. All other drivers door features work and I’m not having any other electrical problems.

I did some googling and it appears other Toyotas and other brands have this issue. No one has really found a solution to intermittent keyless entry. If it heat up the inside of the vehicle it works better lol.
 
Humble Leader - just a thought, when you have this issue - does it involve all doors? There is a history of door lock actuator issues with the 5th gens; so I wonder if the door could be trying to operate correctly, but hindered by the actuator being bad or intermittent.

The thread that discusses this and provides part number info and alternate less expensive source for replacement actuator is by mbumpus11 in Aug 2017. Titled Door lock actuator motor repair.
 
Humble Leader - just a thought, when you have this issue - does it involve all doors? There is a history of door lock actuator issues with the 5th gens; so I wonder if the door could be trying to operate correctly, but hindered by the actuator being bad or intermittent.

The thread that discusses this and provides part number info and alternate less expensive source for replacement actuator is by mbumpus11 in Aug 2017. Titled Door lock actuator motor repair.

Only the drivers side acts up. Passenger and tailgate work fine. There is no beep or anything to let me know the car recognizes my touch but won’t open. Car sees the fob because puddle lights go on. I don’t hear anything mechanical happening. The fob works fine so I don’t think it’s an actuator issue. It’s just weird that replacing the handle solved all problems right away for a short while. And then just randomly the problems came back. The car sat overnight - that’s the only thing that I can think of. Whereas when it was working I was going in and out of the car driving around town and even at home moving things in and out of the vehicle. unlock feature is slow to respond and the lock feature doesn’t work. Previously it was the other way around. Lock would be slow to work and unlock wouldn’t work. I dont see how it could be a fuse or wiring or even the handle at fault. Disconnected 12v once and solved the problem temporarily. New fob battery too.
 
Update to my update : the touch to lock isn’t working anymore and the touch to unlock is slow to work but it works. It’s a good three steamboats before the door handle recognizes my hand there and opens. Passenger and tailgate work fine

Was working fine for a while and now it’s acting up. As soon as the new handle was put in it was immediately fine for a while. Temperature hasn’t really changed the last couple days. No rain either or anything environmental that could cause this.

It’s unlikely a loose connector or a defective handle. It seems when the truck sits for a long period of time it stops working. The first time I noticed issues with the touch system was right before my car battery died. It hasn’t worked right since then on the drivers side. All other drivers door features work and I’m not having any other electrical problems.

I did some googling and it appears other Toyotas and other brands have this issue. No one has really found a solution to intermittent keyless entry. If it heat up the inside of the vehicle it works better lol.

Hi there Humble Leader...,

Here's something you can try! Disconnect the battery and either, leave it disconnected for a minimum of 4 HOURS, or remove the NEG battery post, use a jumper wire and connect it to the POS post for 10 minutes, then reconnect BOTH terminals to the battery normally!

Start the truck; it should stall after 2 seconds! Restart the truck and it'll run normally. Now test the door handles/security system... and Please let us know how you make out...!!:car:

~rig~ Best to you HL!
 
Hi there Humble Leader...,

Here's something you can try! Disconnect the battery and either, leave it disconnected for a minimum of 4 HOURS, or remove the NEG battery post, use a jumper wire and connect it to the POS post for 10 minutes, then reconnect BOTH terminals to the battery normally!

Start the truck; it should stall after 2 seconds! Restart the truck and it'll run normally. Now test the door handles/security system... and Please let us know how you make out...!!:car:

~rig~ Best to you HL!

Tried it today. Left it for 7 hours almost. This might be the last straw for this rig. The repair bills are getting expensive for the age of the truck. Might be time to move on. This looks to be electrical and the harness looks fine so Im approaching a dead end. Tracking gremlins Idk if it’s worth it. Bcm will cost $1k and that’s if I do the work myself.

Maybe I’ll get lucky and it will work randomly again. I’ll give it a couple weeks. I’ve seen this problem with Audi ford and a bit with Prius and highlander. No one seems to have an answer.
 
Tried it today. Left it for 7 hours almost. This might be the last straw for this rig. The repair bills are getting expensive for the age of the truck. Might be time to move on. This looks to be electrical and the harness looks fine so Im approaching a dead end. Tracking gremlins Idk if it’s worth it. Bcm will cost $1k and that’s if I do the work myself.

Maybe I’ll get lucky and it will work randomly again. I’ll give it a couple weeks. I’ve seen this problem with Audi ford and a bit with Prius and highlander. No one seems to have an answer.

Ok, next I would check the new door handle; may be defective! I have yet to see a MAIN-BODY ECU go bad for no reason! If not the door handle, then I'd have to check the wiring in the door and going to the Security Certification ECU, the trouble could be there... so don't give up yet HL!

~rig~ best to you!
 
Ok, next I would check the new door handle; may be defective! I have yet to see a MAIN-BODY ECU go bad for no reason! If not the door handle, then I'd have to check the wiring in the door and going to the Security Certification ECU, the trouble could be there... so don't give up yet HL!

~rig~ best to you!

Haha I had the time to do some testing. I actually used the working passenger handle on drivers side. That’s the one I originally used because I know it works. So the handle is good. When the handle was swapped no resets were done or anything reprogrammed. Just unplug and plug in and that’s when it worked. I will open the door up again but I think the wiring is ok. But…

If I run a space heater inside the vehicle when it’s off and point it at the drivers kick panel near the dead pedal and door area the handle works like it should once the surrounding air is warm. This all started soon after the incident that’s in my avatar took place. I got a bit of water inside the vehicle near the kick panel on drivers side and inside the door. Perhaps related but I’m not having any other electrical issues with the truck and replacing the handle solved this temporarily.

I’ve also noticed for the past few months prior to incident mentioned above that my vehicle is sometimes unlocked the next morning which is strange because I was certain I heard the doors lock before going inside. Happened at the train station too which I always check that I locked the vehicle before walking away since I have my ham radio set up in there. Gremlins gremlins gremlins where are you hiding.
 
Haha I had the time to do some testing. I actually used the working passenger handle on drivers side. That’s the one I originally used because I know it works. So the handle is good. When the handle was swapped no resets were done or anything reprogrammed. Just unplug and plug in and that’s when it worked. I will open the door up again but I think the wiring is ok. But…

If I run a space heater inside the vehicle when it’s off and point it at the drivers kick panel near the dead pedal and door area the handle works like it should once the surrounding air is warm. This all started soon after the incident that’s in my avatar took place. I got a bit of water inside the vehicle near the kick panel on drivers side and inside the door. Perhaps related but I’m not having any other electrical issues with the truck and replacing the handle solved this temporarily.

I’ve also noticed for the past few months prior to incident mentioned above that my vehicle is sometimes unlocked the next morning which is strange because I was certain I heard the doors lock before going inside. Happened at the train station too which I always check that I locked the vehicle before walking away since I have my ham radio set up in there. Gremlins gremlins gremlins where are you hiding.

...Have you tried removing the door sill & kick panel, and get a warm air blower in there to dry it out real good; could be some water in the harness connectors causing this electrical anomaly(?)!

"Let us know!!"
 
...Have you tried removing the door sill & kick panel, and get a warm air blower in there to dry it out real good; could be some water in the harness connectors causing this electrical anomaly(?)!

"Let us know!!"

you're on to something... I had some time early this morning and I decided to go out in the freezing garage and try at it again... I removed the kick panel near the dead pedal and unclipped two harnesses that were easy to get to just to see what I could see. I was able to unclip the harness that runs from the drivers door and on the left side the pins were covered in what looks like wet mud. some liberal use of contact cleaner to get out any moisture on the male and female side and a heat gun to dry it up real nice and put it back in. did another harness as well but it was clean. I found one plug that had some moisture around the pin area but couldn't get it fully unplugged so I blasted some contact cleaner in there to drive out moisture and hit the whole area with a heat gun and a mini heater to dry it up

everything is working so far. it's cold out today and wind chill is making it even colder - left the windows open and the kick panels off to let that cold air in. handle wasn't working this morning when I went out so if it's working this afternoon when the cab is ice cold I think I found the gremlin. been chasing this one for almost a month.

thanks for you help btw rig and fly. I didn't mean to commandeer this thread but there isn't a lot of info on this problem and maybe someone else can use this info in the future
 
update - very cold last night. car sat all day with windows open and all night outside in the drive. door handle has been working fine. I think the gremlin has been found. yay- about a months worth of trying to solve this
 
I purchased a used MPX from ebay and installed it this past Sunday. My previous one had water damage and when I installed the new-ish used one the main issue I was having was the 10-second deadline of locking the doors or using the key faub was fixed, but I wasn't able to program the key faub. I assumed it was due to not having the MPX flashed or reprogrammed yet.

So I brought it to the local Toyota dealership first thing the next morning. They kept the car for 2 and 1/2 days. At the end of days 1 and 2 they said they were getting weird codes and couldn't get it to sync. Finally, on day 3 they told me they couldn't get it to work. They quoted me $1,600 to install a new one. I immediately declined that.

It was really frustrating because I don't know if they were just dragging me along and were always going to try and force a new MPX install OR if the used part was faulty. I reached out to the person who sold it to me and explained. They said it worked fine before sending it and would take it back if I wanted to send it.

I am not sure if I should try somewhere else or return the part and try again. The problem with both solutions is I am potentially back in the same situation trying to get it flashed unless I purchase a brand new one.

Any experience or feedback with this situation is greatly appreciated!
 

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