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Discussion Starter #1
Our 2011 Touring has always been temperamental in very cold weather. I've got a big issue that didn't go away with warmer temps and I can't solve though. Maybe someone has has a similar experience. Sorry, this a long one as I've tried to include everything I know.

My Wife reported an inability get the POWER TAILGATE open on a trip out of state. When she got back, I checked pulled DTC with my HDS scanner, checked all fuses, ran through troubleshooting procedures on tailgate switches and motors. Everything tested OK. You can open the tailgate manually from outside of the ignition is in the "ON" postion, but not ACC or off. Power tailgate won't open or close from inside button or key. Codes were as follows:
  • B1142 - Door multiplex control unit lost communication with front passenger's power window switch (UART line open)
  • U0230 - Gauge control module lost communication with power tailgate control unit
  • B1245 - A short in the rear air mix control motor circuit
I cleared codes per the service manual. None of them returned.

However.....

I soon realized that the POWER TAILGATE was not the only thing that wasn't working. NAV SYSTEM is dead. Not even the warning screen on startup. Nav Unit under the drivers seat will not eject the disc. REAR ENTERTAINMENT SYSTEM will not come on. FRONT MAP LIGHTS will not come on. At the moment, those are the only other things I've identified.

Looking at wiring diagrams, PTG, NAV and RES all route through the "Multiplex Integrated Control Unit" (MICU). I went on to do the "MICU reset procedure", aka battery cable reset. Battery cables were jumped, key put ignition and set to "ON" for 10 minutes. No change in behavior or affected circuits.

I began doing function tests with my HDS and confirmed that the inside tailgate switch is functional as are all components I previously tested in the tailgate If I put tailgate up and try to close it with the inside tailgate button, I get the following code:
  • B1388 - Power tailgate drive motor circuit malfunction
The service manual the lead me to gutting the back of the vehicle in an effort to reach the tailgate control module for testing. I ran out of time and to finish the job requires removing 3rd row seats and cargo tray. I'm skeptical that this is the right path anyway.

Has anyone experience multiple failures like this? I've got my eye on the MICU, which runs PTG, NAV and RES. All three systems also pass through the Power Window Master Switch, which as of right now, I have not tested.

-

Sadly, this is not the only issue. Again, when temps are well below zero, the D3 switch on the shifter will engage randomly. This is particularly problematic on the highway at 75mph. I have yet to begin even looking into the roots of that issue, but throwing it out there for consideration as part of a larger overall electrical issue.

Any help or input greatly appreciated.
 

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Our 2011 Touring has always been temperamental in very cold weather. I've got a big issue that didn't go away with warmer temps and I can't solve though. Maybe someone has has a similar experience. Sorry, this a long one as I've tried to include everything I know.

My Wife reported an inability get the POWER TAILGATE open on a trip out of state. When she got back, I checked pulled DTC with my HDS scanner, checked all fuses, ran through troubleshooting procedures on tailgate switches and motors. Everything tested OK. You can open the tailgate manually from outside of the ignition is in the "ON" postion, but not ACC or off. Power tailgate won't open or close from inside button or key. Codes were as follows:
  • B1142 - Door multiplex control unit lost communication with front passenger's power window switch (UART line open)
  • U0230 - Gauge control module lost communication with power tailgate control unit
  • B1245 - A short in the rear air mix control motor circuit
I cleared codes per the service manual. None of them returned.

However.....

I soon realized that the POWER TAILGATE was not the only thing that wasn't working. NAV SYSTEM is dead. Not even the warning screen on startup. Nav Unit under the drivers seat will not eject the disc. REAR ENTERTAINMENT SYSTEM will not come on. FRONT MAP LIGHTS will not come on. At the moment, those are the only other things I've identified.

Looking at wiring diagrams, PTG, NAV and RES all route through the "Multiplex Integrated Control Unit" (MICU). I went on to do the "MICU reset procedure", aka battery cable reset. Battery cables were jumped, key put ignition and set to "ON" for 10 minutes. No change in behavior or affected circuits.

I began doing function tests with my HDS and confirmed that the inside tailgate switch is functional as are all components I previously tested in the tailgate If I put tailgate up and try to close it with the inside tailgate button, I get the following code:
  • B1388 - Power tailgate drive motor circuit malfunction
The service manual the lead me to gutting the back of the vehicle in an effort to reach the tailgate control module for testing. I ran out of time and to finish the job requires removing 3rd row seats and cargo tray. I'm skeptical that this is the right path anyway.

Has anyone experience multiple failures like this? I've got my eye on the MICU, which runs PTG, NAV and RES. All three systems also pass through the Power Window Master Switch, which as of right now, I have not tested.

-

Sadly, this is not the only issue. Again, when temps are well below zero, the D3 switch on the shifter will engage randomly. This is particularly problematic on the highway at 75mph. I have yet to begin even looking into the roots of that issue, but throwing it out there for consideration as part of a larger overall electrical issue.

Any help or input greatly appreciated.
My condolences as electrical issues are always the hardest problem to trace. The last electrical problem I had was with an Odyssey in which the actual problem was traced to the ENTIRE under the hood fuse box. Given the multitude of electrical issues you're experiencing it wouldn't hurt to test it out. Intermittent connections were causing haywire and weird issues. Maybe cleaning the connections and applying dielectric grease may help. This would be the easiest thing to do first. Also I would cover the basics, such as checking all pertinent fuses and relays. I believe the MICU on Honda's has the relay's built into the unit. In my experience I've never had a MICU go bad, but if you happen to have a spare or maybe can get one from a junk yard, switch it out to test it. Or you could possibly disassemble the MICU and look for any bad solder joints. Extreme hot and cold temps can form cracks in the solder joints.
 

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Our 2011 Touring has always been temperamental in very cold weather. I've got a big issue that didn't go away with warmer temps and I can't solve though. Maybe someone has has a similar experience. Sorry, this a long one as I've tried to include everything I know.

My Wife reported an inability get the POWER TAILGATE open on a trip out of state. When she got back, I checked pulled DTC with my HDS scanner, checked all fuses, ran through troubleshooting procedures on tailgate switches and motors. Everything tested OK. You can open the tailgate manually from outside of the ignition is in the "ON" postion, but not ACC or off. Power tailgate won't open or close from inside button or key. Codes were as follows:
  • B1142 - Door multiplex control unit lost communication with front passenger's power window switch (UART line open)
  • U0230 - Gauge control module lost communication with power tailgate control unit
  • B1245 - A short in the rear air mix control motor circuit
I cleared codes per the service manual. None of them returned.

However.....

I soon realized that the POWER TAILGATE was not the only thing that wasn't working. NAV SYSTEM is dead. Not even the warning screen on startup. Nav Unit under the drivers seat will not eject the disc. REAR ENTERTAINMENT SYSTEM will not come on. FRONT MAP LIGHTS will not come on. At the moment, those are the only other things I've identified.

Looking at wiring diagrams, PTG, NAV and RES all route through the "Multiplex Integrated Control Unit" (MICU). I went on to do the "MICU reset procedure", aka battery cable reset. Battery cables were jumped, key put ignition and set to "ON" for 10 minutes. No change in behavior or affected circuits.

I began doing function tests with my HDS and confirmed that the inside tailgate switch is functional as are all components I previously tested in the tailgate If I put tailgate up and try to close it with the inside tailgate button, I get the following code:
  • B1388 - Power tailgate drive motor circuit malfunction
The service manual the lead me to gutting the back of the vehicle in an effort to reach the tailgate control module for testing. I ran out of time and to finish the job requires removing 3rd row seats and cargo tray. I'm skeptical that this is the right path anyway.

Has anyone experience multiple failures like this? I've got my eye on the MICU, which runs PTG, NAV and RES. All three systems also pass through the Power Window Master Switch, which as of right now, I have not tested.

-

Sadly, this is not the only issue. Again, when temps are well below zero, the D3 switch on the shifter will engage randomly. This is particularly problematic on the highway at 75mph. I have yet to begin even looking into the roots of that issue, but throwing it out there for consideration as part of a larger overall electrical issue.

Any help or input greatly appreciated.
My 2011 Touring has a passenger RV mirror that is out of whack ever time I start the car. I also have a courtesy light not working on the driver's side passenger. Not getting any juice at the sock.
Bought the rig new. I'm afraid to pay the labor for the hours of troubleshooting.
Love my Pilot, 115k miles basically worry-free, but itching for a 2020.
 

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Discussion Starter #4
My condolences as electrical issues are always the hardest problem to trace. The last electrical problem I had was with an Odyssey in which the actual problem was traced to the ENTIRE under the hood fuse box. Given the multitude of electrical issues you're experiencing it wouldn't hurt to test it out. Intermittent connections were causing haywire and weird issues. Maybe cleaning the connections and applying dielectric grease may help. This would be the easiest thing to do first. Also I would cover the basics, such as checking all pertinent fuses and relays. I believe the MICU on Honda's has the relay's built into the unit. In my experience I've never had a MICU go bad, but if you happen to have a spare or maybe can get one from a junk yard, switch it out to test it. Or you could possibly disassemble the MICU and look for any bad solder joints. Extreme hot and cold temps can form cracks in the solder joints.
Thanks alzeal.

I've seen a Civic underhood fuse box fail. my Neice's boyfriend and I spent a day chasing a problem on his car. With nothing left to check, we swapped it with a junkyard box and, boom, problem solved.

I think the fuse box or control unit are the problem. The MICU is part of the under dash fuse box, but I haven't yet checked if it's removeable from, or part of, the fuse box.

Our Volvo @ 185k has begun running through relays too. I've replaced both headlight relays on the control unit board. I'd say this is also a distinct possibility. Contacts on those Volvo headlight relays were burned to a crisp.

My 2011 Touring has a passenger RV mirror that is out of whack ever time I start the car. I also have a courtesy light not working on the driver's side passenger. Not getting any juice at the sock.
Bought the rig new. I'm afraid to pay the labor for the hours of troubleshooting.
Love my Pilot, 115k miles basically worry-free, but itching for a 2020.
oderman, I think the map lights and mirrors also run through MICU, but maybe also drivers side window control unit. I'll double check my diagram, but drivers window control unit is also an integrated system for more stuff than you'd think.

---

Just to update, we put about 600 miles on the Pilot since my last post with holiday travel. Last Saturday, the NAV screen began flickering on the highway. About 5 minutes later, it came on, stayed on and asked for the security code. I entered the code at the next rest stop and the system began working. 20 minutes later, it went back off and never came back on again over the following 300 miles.

I hope to be able to spend some more time working on it this weekend and will post back.
 

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Discussion Starter #5
I've been putting in at least an hour per weekend on diagnosis, but no real answers.

I'm ready to just roll the dice on a new or used interior fuse box. The multiplex controller just has to be the problem.

QUESTION, do I definitely need the fuse box with the same part number I'm getting on oem part sites? I've found a used box from a 2011 Touring, but the part code is 38200-SZA-A30 instead of A33.

New fuse box is an option, but it's 3x more $.
 

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Discussion Starter #6
Well, I tried an under dash fuse box from a wreck. No change in problems with Power Tailgate, Nav System, RES and front map lights. All other systems functioned properly.

The vehicle continues to throw additional electrical issues at me that I've been able to resolve. I got P3400 last week for VPS failure. I swapped the oil pressure sensors to see if it would give me the opposite code and isolate one of the sensors as the problem. Instead, it solved the issue and it's never come back. WTF?

I also got a multple DTCs for VTM4 failure. Cleared them, road tested, never came back.

I'm officially out of ideas. At a minimum, I MUST get this tailgate working again even if I can't repair the other dead systems. A final plea for anyone out there who might have something else to look into.
 
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