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Discussion Starter #1
We've bought a 2019 sport hybrid with the advanced packageand going through all the documentation and looking at the car I have a couple of questions that looking for some help on.

1) on the hybrid under the hood, down low on the drivers side near the firewall there are two off white reservoirs with screw tops that say ATF type DW-1. The manuals make no mention I could find and I'm trying to find out what they go to.
2) In the manual it says that on the MID one display shows the torque management to each of the wheels etc. I can get that on the main center display but no such display shows on the MID. There is one that shows which mode I'm in (comfort, normal sport, sport+) but no torque info . Any clues on this?
 

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We've bought a 2019 sport hybrid with the advanced packageand going through all the documentation and looking at the car I have a couple of questions that looking for some help on.

1) on the hybrid under the hood, down low on the drivers side near the firewall there are two off white reservoirs with screw tops that say ATF type DW-1. The manuals make no mention I could find and I'm trying to find out what they go to.
2) In the manual it says that on the MID one display shows the torque management to each of the wheels etc. I can get that on the main center display but no such display shows on the MID. There is one that shows which mode I'm in (comfort, normal sport, sport+) but no torque info . Any clues on this?
About the two reservoirs: One is for the brake fluid, the other is coolant for the high voltage battery system control. (The battery pack itself is air cooled with air from the cabin.) Facing the rear of the car, the brake fluid is on the left, the coolant on the right. These should have very different looking caps. The coolant is the same as fluid as the engine coolant. Or maybe you're looking at the DCT fluid fill? I haven't seen those. On the other issue, I've only seen the hybrid power flow diagram on the upper center (split) screen, not on the MID. My car is a 2018 Advance.
114566
 

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We've bought a 2019 sport hybrid with the advanced packageand going through all the documentation and looking at the car I have a couple of questions that looking for some help on.

1) on the hybrid under the hood, down low on the drivers side near the firewall there are two off white reservoirs with screw tops that say ATF type DW-1. The manuals make no mention I could find and I'm trying to find out what they go to.
2) In the manual it says that on the MID one display shows the torque management to each of the wheels etc. I can get that on the main center display but no such display shows on the MID. There is one that shows which mode I'm in (comfort, normal sport, sport+) but no torque info . Any clues on this?
1. If you included a picture, we could help to identify.
2. I never see torque management on my 2019 SH MID display as well. This probably only available on the standard AWD version, but whoever created the Hybrid manual didn't bother to double check before publishing it.
 

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Discussion Starter #4
About the two reservoirs: One is for the brake fluid, the other is coolant for the high voltage battery system control. (The battery pack itself is air cooled with air from the cabin.) Facing the rear of the car, the brake fluid is on the left, the coolant on the right. These should have very different looking caps. The coolant is the same as fluid as the engine coolant. Or maybe you're looking at the DCT fluid fill? I haven't seen those. On the other issue, I've only seen the hybrid power flow diagram on the upper center (split) screen, not on the MID. My car is a 2018 Advance. View attachment 114566
I'm aware of these two reservoirs. the reservoirs I'm referring to are down below these two, I'll see if I can post a picture of them. the tops of both say ATF DW-1 and each have a black tube coming out of the reservoir cap.
 

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Discussion Starter #5
1. If you included a picture, we could help to identify.
2. I never see torque management on my 2019 SH MID display as well. This probably only available on the standard AWD version, but whoever created the Hybrid manual didn't bother to double check before publishing it.
on (2) sure looks like it is another error in the manual. I've found a few others so far.
on (1) I'll post a picture soon.
 

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I'm aware of these two reservoirs. the reservoirs I'm referring to are down below these two, I'll see if I can post a picture of them. the tops of both say ATF DW-1 and each have a black tube coming out of the reservoir cap.
I've just gone out to the garage again, and with a flashlight and a careful look, I have nothing like what you're describing. I'm now wondering if they're overflow containers for the DCT when it's hot. I once saw such a system on a Subaru with a CVT. Mine is a 2018, and perhaps they've changed something? I'd love to see a photo if you can do it.
 

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Thanks for the photo. I found them in my 2018, I simply wasn't expecting something located that far down. Given the position and ATF markings, they must for a fill for the DCT and perhaps some kind of gearing between the gasoline engine and motor. I don't believe this car has a starter motor, I believe the engine is cranked by the electric motor between it and the DCT, and I'd wonder if that could be done without a gear system between the two. I have a very good service manager at my dealer and when I have the time I'll ask him about all of this. (Incidentally, I'm also not sure this car has an alternator on the engine. I believe the 12 volt battery is charged by the controller for the high voltage system.)
 

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Discussion Starter #9
Thanks for the photo. I found them in my 2018, I simply wasn't expecting something located that far down. Given the position and ATF markings, they must for a fill for the DCT and perhaps some kind of gearing between the gasoline engine and motor. I don't believe this car has a starter motor, I believe the engine is cranked by the electric motor between it and the DCT, and I'd wonder if that could be done without a gear system between the two. I have a very good service manager at my dealer and when I have the time I'll ask him about all of this. (Incidentally, I'm also not sure this car has an alternator on the engine. I believe the 12 volt battery is charged by the controller for the high voltage system.)
Thanks for the feedback. Yes, those two reservoirs certainly are hidden. Almost like it was done on purpose.

On the alternator, I agree there isn't a seperate alternator that I could see, the charging system is likely a dual output from the high voltage charger, one for charging the battery pack, one for the 12V battery. But since the motors are AC syncronous motors, when running them as a generator the output is AC, so in effect for charging it's a big alternator.

And I've never hear anything that sounds like a bendix drive and as quick as the motor spins over, nor could I see a starter motor on casual observation, so I agree, the starting motor is likely the AC motor on the engine. However, what that would mean is a discharged High voltage battery pack and a fully charged 12V may still mean no start. And at times when I pull into the garage the High voltage pack is near empty of charge. So it would be interesting to find out exactly how the engine is started when real cold outside.

As for the two ATF reservoirs, I don't think either goes to the DTC or TMU. Looking at the DTC for fill and drain, and no dipstick to check fill, it appears that the DTC and TMU are like a typical manual gearbox and rear diff. A train plug and a fill plug where you fill till ATF starts to dribble out the fill plug. But then I could be completely off base and wrong.

I've got a portable lift system in the garage, and this next week with not much to do and rain in the forecast, I plan on putting the MDX on the lift and see if I can trace out the hose from the two reservoirs and see where they go.
 

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Thanks for the feedback. Yes, those two reservoirs certainly are hidden. Almost like it was done on purpose.

On the alternator, I agree there isn't a seperate alternator that I could see, the charging system is likely a dual output from the high voltage charger, one for charging the battery pack, one for the 12V battery. But since the motors are AC syncronous motors, when running them as a generator the output is AC, so in effect for charging it's a big alternator.

And I've never hear anything that sounds like a bendix drive and as quick as the motor spins over, nor could I see a starter motor on casual observation, so I agree, the starting motor is likely the AC motor on the engine. However, what that would mean is a discharged High voltage battery pack and a fully charged 12V may still mean no start. And at times when I pull into the garage the High voltage pack is near empty of charge. So it would be interesting to find out exactly how the engine is started when real cold outside.

As for the two ATF reservoirs, I don't think either goes to the DTC or TMU. Looking at the DTC for fill and drain, and no dipstick to check fill, it appears that the DTC and TMU are like a typical manual gearbox and rear diff. A train plug and a fill plug where you fill till ATF starts to dribble out the fill plug. But then I could be completely off base and wrong.

I've got a portable lift system in the garage, and this next week with not much to do and rain in the forecast, I plan on putting the MDX on the lift and see if I can trace out the hose from the two reservoirs and see where they go.
Everything you're saying makes sense to me. On the "dead" high voltage system and the engine start, I doubt the control system would allow the high voltage battery to deplete to that extent. The system might allow, let's say, 10% but then it would stop any discharge to protect the h.v. battery but use it to start the engine if need be. (Just a guess of course.) In about 6,000 miles and two years of driving, I've never seen the h.v. battery level go below 20 or 25% or so, and that's only in extended stop-and-go traffic. And I wonder if somehow things are set up to allow the 12 v battery to drive the "sandwich" motor for an engine start. (Seems unlikely.) When you start your car with a largely depleted h.v. battery, maybe you could have the power flow screen on and see what flows where. The engine start from cold is so smooth and refined that it certainly isn't a conventional starter motor. (I'm a retired pilot, and the engine start reminds me of the start with a turbine.) But I also wonder if the rotational speed of the sandwich motor could allow it to be directly connected to the engine crankshaft for a start. And if the two reservoirs are not for the DTC & TMU I'd like to know what they do, and I hope you'll post your your findings. I know that the TMU drains and fills conventionally like a differential, but I haven't seen the DTC. But if not for the DTC, what could these two reservoirs specifying ATF be for? It is an amazingly complex and refined system, which is why I like the car so much. I'm waiting for your observations!
 

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Discussion Starter #11
ok, a few more pictures. Put the car up on my portable lift today, did some poking around and took some pictures. It does look like the two reservoirs are something that interacts with the transmission system. And I did find instructions on replacing DCT transmision fluid. It's like on rear diff's, manual transmissions etc. with a drain plug and filler plug. Instructions are a little different than one might expect to do. First, they have you stop draining once the flow turns to a slow flow, not continuing to let it drain. Next, as expected, fill till it starts to drip out of the fill tube. (while keeping the car LEVEL as one would expect. But then instructed to run the car for 30 seconds while selecting various gears, kinda like a typical automatic, then shutting it down and opening the fill plug and checking and adding fluid if needed.

So...... the two reservoirs may be related to something in the transmission. They do both have a "min" and "max" level, now how one would check that is beyond me, and the two rubber hoses off the top of each cap go directly down into the unit below.
So a little more info, but still not completely sure what they go to nor the function. Don't think I'll be changing transmission fluid till I find out exactly what they are.

I wonder (and it's just a guess) if these are the control units for the clutches. Maybe they are hydraulically actuated.

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Discussion Starter #12
well, after some searching and signing up for a months access to honda techinfo, the two units are indeed the clutch actuator modules. And some further searching regarding transmission drain/fill, once you do the initial fill, the next step is to enter the "maintenance mode" start the car, run it for 30 seconds, then turn the car off and within 10 minutes check the fluid level and add fluid till it is at up to the edge of the fill plug. Maint. mode entails, turn on ignition, foot off the brake, hitthe gas x times, followed by the brake then gas again while rubbing your stomach and patting your head, then start the car.....
 

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well, after some searching and signing up for a months access to honda techinfo, the two units are indeed the clutch actuator modules. And some further searching regarding transmission drain/fill, once you do the initial fill, the next step is to enter the "maintenance mode" start the car, run it for 30 seconds, then turn the car off and within 10 minutes check the fluid level and add fluid till it is at up to the edge of the fill plug. Maint. mode entails, turn on ignition, foot off the brake, hitthe gas x times, followed by the brake then gas again while rubbing your stomach and patting your head, then start the car.....
MCRacer, thank you for all your research and effort! The clutch actuators make sense, and I thought so in your first, previous conjecture. They look like they're attached to the transmission case. Best, Wally
 

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Discussion Starter #14
On the starter, based on wiring diagrams I found, at least on a start using the keyless go, it shows a 12V starter motor. I'm going to bet that when underway or under battery power starting is from the HV battery and electric motor. That may be how it starts once from a stop as well.
 

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On the starter, based on wiring diagrams I found, at least on a start using the keyless go, it shows a 12V starter motor. I'm going to bet that when underway or under battery power starting is from the HV battery and electric motor. That may be how it starts once from a stop as well.
On the starter, based on wiring diagrams I found, at least on a start using the keyless go, it shows a 12V starter motor. I'm going to bet that when underway or under battery power starting is from the HV battery and electric motor. That may be how it starts once from a stop as well.
On the starter, based on wiring diagrams I found, at least on a start using the keyless go, it shows a 12V starter motor. I'm going to bet that when underway or under battery power starting is from the HV battery and electric motor. That may be how it starts once from a stop as well.
Thanks again. If there's a 12v starter when cold, it's all incredibly smooth. When I'm driving and come to a stop, there is a very small, barely perceptible stumble on start up, but when the car is moving it's completely imperceptible. So I have no idea what accounts for the three different feels.
 

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Thanks again. If there's a 12v starter when cold, it's all incredibly smooth. When I'm driving and come to a stop, there is a very small, barely perceptible stumble on start up, but when the car is moving it's completely imperceptible. So I have no idea what accounts for the three different feels.
yup, I agree completely. I'd bet money that when moving the electric motor is the starter. And highly likely the same thing after stopping when in drive. Trying to pay attention, a cold start seems more like a typical starter motor, but smoother and no "bendix drive" noise. But then the car is so sound insulated, it just may be that the bendix noise isn't heard inside the car. Without the tach, I would defy anyone to tell when the engine shuts off or start up when the car is in motion. Now if they use the electric motor for starting during a drive cycle, it's a 40+HP motor turning over the car, not a few HP or less geared down starter motor.
 
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