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Discussion Starter · #1 ·
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I will try and keep things simple. Do not comment on this thread until I have finished with my posts. There will be several posts in this thread, broken up into logical sections. If someone posts in this thread before I am finished, I will stop sharing the information. If you want to “Like” something, go for it. Just don’t comment until I have completed my goal. You will know when it is time to comment. I expect this thread to take a few days to complete.

What I plan on doing is describing with words, and eventually posting a wiring diagram for the Power Rear Gate (PRG) System. The PRG system has been the source of much displeasure to say the least by people who wish to leave their PRG open for hours on end only to find that this creates a large draw on the battery and renders the vehicle unable to start. This has not happened to me, but I purchased access to the Ascent manuals including the wiring diagrams. I will not post those items for legal/copyright issues, but have no problem recreating them in an easier to decipher manner such that it can fit on one page in a pdf for reference.

My hope is that someone who is familiar with car electronics will take this information and develop a workaround for this issue.

Thanks

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Discussion Starter · #2 ·
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PRG CIRCUITS
The PRG system is part of 3 circuits, or sources of power. They are:
  • MB-23
  • FB-9
  • FB-46
Of course, an “easy” method to our problem would be to pull the fuses for these circuits, but fuses are not meant to removed and re-inserted multiple times. Furthermore, these circuits control more than one system as described below.

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Discussion Starter · #3 ·
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MB-23

MB-23 is defined as the “Power Window Circuit Breaker”. Its fuse is in the Engine Compartment Side, identified as Slow Blow Fuse (SBF)-5. It is a 30A fuse. In addition to the PRG system, the MB-23 circuit is the source for:
  1. Power Seat System
  2. Power Window System
  3. Sunroof Control System
As far as routing, to get from the fuse to the PRG control module, it looks something like this:
  1. BLACK wire w/WHITE stripe to terminal #1 on connector B41. This is where the Power Window Circuit Breaker is.
  2. WHITE wire from terminal #2 on connector B41 to bulkhead wiring harness connector B60, terminal #1.
  3. The instrument panel wiring harness connector (i112) takes this signal along a RED wire to instrument panel harness connector (i282). This should physically travel from the driver’s side to the passenger’s side behind to connect to the Rear Wiring Harness
  4. There should be a large connector for the Rear Wiring harness, R464. This wire bundle travels toward the rear of the vehicle in the floor.
  5. From terminal #10 in R464, there is a WHITE wire which connects to the PRG CM. It connects using Connector R423 (this connector has 6 terminals), terminal #1.
  6. This concludes the PRG portion of circuit MB-23.
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Discussion Starter · #4 · (Edited)
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FB-9

The FB-9 circuit is powered through fuse #14 in the Passenger Room Side box. This is a 10A fuse. In addition to the PRG system, the FB-9 circuit also includes the following:
  1. Electronic Parking Break (EPB) Control switch
  2. Rearview mirror
  3. TPMS CM/Keyless Entry System
For completeness, this #14 fuse also controls the FB-10, FB-11, FB-14 circuits which have the following systems:
  • Combination meter
  • A/C CM
  • A/C control panel
  • Door Lock back-up unit
  • Rear A/C
  • Auto headlight beam leveler CM
For all systems from this circuit, there should be a LIME GREEN wire w/YELLOW stripe from the GREY fuse box connector i136, terminal #19) and spliced to each system:
  1. Wired into terminal #6 on connector i163 for the EPB
  2. Wired into terminal #1 on connector i339/R303 which connects as a RED wire to the rearview mirror terminal #6 on connector R416
  3. Wired into terminal #30 on connector i282/R464 which connects as a PINK wire into terminal #12 on connector R221 for the TPMS
But I digress and back to the PRG system…
  1. The LIME GREEN w/YELLOW wire should also connect to the same i282/R464 area to be routed rearward. It also uses terminal #30 at this point.
  2. As it connects to the PRG CM, is uses connector R423, terminal #6. This should be a PINK wire.
  3. This concludes the PRG portion of the circuit
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Discussion Starter · #5 ·
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FB-46

The FB-46 circuit is powered through fuse #19 in the Passenger Room Side box. This is a 10A fuse. In addition to the PRG system, the FB-46 circuit also includes the following:
  1. RAB CM
  2. Radar sensor LH
  3. Radar Sensor RH
  4. TPMS

For completeness, this #19 fuse also controls the FB-47, FB-48, FB-49 circuits which have the following systems:
  1. BSD/RCTA
  2. Data link connector
  3. Remote Engine Start CM
  4. Glass Roof CM
  5. Hazard Switch
  6. Rain Sensor
  7. Rearview Mirror
  8. Shade CM
  9. Stereo Camera
  10. Stop Light & brake switch

For all systems in this circuit, there should be a GREY wire w/WHITE stripe from the BLUE fuse box connector (i5, terminal #8) and spliced to each system:
  1. Wired into terminal #1 on connector i284/R466 for the RAB
  2. Wired into terminal #8 on connector i284/R466, which connects as a WHITE wire into terminal #5 on the LH Radar Sensor
  3. Wired into terminal #8 on connector i284/R466, which connects as a WHITE wire into terminal #5 on the RH Radar Sensor
  4. Wired into terminal #31 on connector i282/R464 which connects as a BLUE wire into terminal #6 on connector R221 for the TPMS
But I digress and back to the PRG system…
  1. The GREY w/WHITE wire should also connect to the same i282/R464 area to be routed rearward. It also uses terminal #31 at this point.
  2. As it connects to the PRG CM, is uses connector R422, terminal #16. This should be a BLUE wire.
  3. This concludes the PRG portion of the circuit
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Discussion Starter · #6 ·
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OTHER INPUTS TO PRG CM

In addition to the three “power” wires coming from the front of the vehicle to the PRG CM, there are also four other “inputs” that travel with them. Two of these wires come from the driver’s side switches:
  1. Power Rear Gate Driver’s Switch
  2. Memory Height Switch
The other two come from other units:
  1. Body Integrated Unit
  2. Hazard Switch Assembly
The first three of these wires travel from the driver’s side (Instrument Panel Wiring Harness LH) to the passenger side (Instrument Panel Wiring Harness RH). They are connected to the Rear Wiring Harness at the same i282/R464 junction that the three power wires reside. The Hazard Switch already belongs to the Instrument Panel Wiring Harness RH.

  1. The PRG driver’s switch wire begins at terminal #1 in connector i258. It is a WHITE wire which terminates at i282/R464 at terminal #37. This signal is carried to the PRG CM via a WHITE wire in connector R422, terminal #13.
  2. The Memory Height Switch wire begins at terminal #1 in connector i93. It is a RED wire which terminates at i282/R464 at terminal #38. This signal is carried to the PRG CM via a LIGHT GREEN wire in connector R422, terminal #8.
  3. The BIU wire begins at terminal #18 in connector i81. This wire is spliced multiple times and wired to:
  • Power Seat CM
  • Shade CM
  • Glass Roof CM
  • Rain Sensor
It is a YELLOW wire w/PINK stripe. For the PRG system, it terminates at i282/R464, terminal #39. From there it becomes a BLUE wire to connector R422, terminal #14 at the PRG CM.

4. The Hazard Switch Assembly wire begins at terminal #5 in connector i333. It is a GREEN wire w/RED stripe which terminates at i282/R464 at terminal #40. This signal is carried to the PRG CM via a GREY wire in connector R422, terminal #15.

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Discussion Starter · #7 ·
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OUTPUTS FROM PRG CM

The PRG CM accepts three connectors. Two of them have already been described: R422 and R423. The third connector is R424. All three of these connectors provide “outputs” or signals to other components in the PRG system. They are:
  1. PRG Drive Unit
  2. PRG Buzzer
  3. PRG Auto Closer
  4. PRG Inner Switch
  5. PRG Touch Sensor RH
PRG DRIVE UNIT

The PRG Drive Unit is connected using an 8-pin connector, R214. Seven of these wires go back to connector R424 on the PRG. The last wire at terminal #7 is used for GROUND.


The other four components are connected from the PRG CM into the physical lift gate. The first connection is at the R38/D34 connection in the upper part of the gate. There is another connection point* at D155/D156 which connects the Upper Gate Cord to the Lower Gate Cord on the driver’s side of the gate, about half way down. From the D156 connector, the components are linked.

PRG BUZZER

Two wires are needed for the PRG Buzzer routing. The first wire begins at the PRG CM using connector R424, terminal #6, a WHITE wire goes to terminal #6 at the first junction. Stays WHITE at the second junction, terminal #5. Stays WHITE at D152 connector, terminal #1 at the buzzer. The second wire begins at the PRG CM using connector R424, terminal #5, a GREY wire goes to terminal #5 at the first junction. Stays GREY at the second junction, terminal #15. Stays GREY at D152 connector, terminal #2 at the buzzer.

PRG AUTO CLOSER

Five wires are needed to route from the PRG CM to the AUTO CLOSER. Four of these wires follow the same path as the buzzer: CM to R38/D34 to D155/D156 to component. One wire follows a slightly different path*.

  1. R422, terminal#3, GREEN wire to terminal #9, GREEN wire, terminal #7, GREEN wire to connector D153 on the Auto Closer, terminal #5
  2. R422, terminal#5, LIGHT BLUE wire to terminal #8, LIGHT BLUE wire, terminal #17, LIGHT BLUE wire to connector D153 on the Auto Closer, terminal #6
  3. R423, terminal#3, YELLOW wire to terminal #1, YELLOW wire, terminal #20, YELLOW wire to connector D153 on the Auto Closer, terminal #2
  4. R423, terminal#2, GREEN wire to terminal #2, GREEN wire, terminal #11, PINK wire to connector D153 on the Auto Closer, terminal #1
  5. *R422, terminal#4, LIGHT GREEN wire to terminal #10, LIGHT GREEN wire, terminal #7 to the D80/D81 connection, LIGHT GREEN wire to connector D153 on the Auto Closer, terminal #3
  6. On the D153 connector, terminal #4 is connected to GROUND using a BLACK wire.
PRG INNER SWITCH

The Inner switch is the button on the gate to close it. There is one wire from the PRG CM. It starts at connector R422, terminal #6 as a BROWN wire. It routes to the R38/D34 connection at terminal #11. IT changes color to a BLUE wire for the D155/D156 connection at terminal #16. It stays BLUE to connector D154, terminal #2 at the Inner switch. Terminal #1 is GROUND with a BLACK wire.

PRG TOUCH SENSOR RH

The PRG Touch sensors are the sensors which check for obstructions upon gate closing. There is one wire from the PRG CM. It starts at connector R422, terminal #1 as a VIOLET wire. It routes to the R38/D34 connection at terminal #12. It stays a VIOLET wire for the D155/D156 connection at terminal #6. It stays VIOLET to connector D151/D108, terminal #1 at the Touch Sensor. Terminal #2 at the RH sensor is connected to the LH sensor with a YELLOW wire at D150/D107, terminal #1. Terminal #2 at connector D107 is GROUND with a BLACK wire.


This concludes the “word” portion of this exercise describing the PRG system. Diagramming the system, connections, wires, etc is next. It may take a few days, but hopefully people can start work on a solution. After the pictures come, another post will follow describing the FSM instructions to physically get access to the PRG CM and the wires.

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Discussion Starter · #8 ·
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Thank you for your patience. I really wanted to do a better job with the wiring diagram, but I just can't do it. Software-ly challenged I am.

Attached is a pdf with a pictorial reference of the PRG wiring system. Do not read into the colors depicted, but refer to the wire table for the true colors. The Wire IDs are my numbering scheme

Use at your own risk. I have not verified physically that the diagram is correct to the vehicle, but it is accurate as best I can tell to Subaru's manual. I hope this helps people and more people are willing to share time and solutions to this "issue".

Thanks


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Discussion Starter · #9 ·
UPDATE
So far the PDF has been viewed 9 times. There will need to be an update to this PDF, hopefully tonight. I will version it accordingly. I really was hoping I was done.

In being asked a question about another fuse, I stumbled upon another circuit which has PRG components, but were not listed in Subaru's PRG system wiring diagram. Here is the update in word form:

FB-22 (LED around the switch)
  1. Power from F/B Fuse #26, WHITE wire w/BLACK stripe to terminal #46 in i282/R464 connector
  2. LIME GREEN wire to terminal #3 at R38/R34 connector
  3. PINK wire to terminal #8 at D155/D156 connector
  4. LIGHT BLUE wire to terminal #3 D154 connector at PRG inner switch
FROM BIU To INNER SWITCH
  1. Starting as BLUE wire w/YELLOW stripe from BIU connector i84, terminal #8 to connector i282/R464 terminal #47
  2. BEIGE wire to terminal #4 at R38/R34 connector
  3. BEIGE wire to terminal #2 at D155/D156 connector
  4. BEIGE wire to terminal #4 at D154 connector PRG Inner switch
Additonal BIU wire
  1. Starting as GREY wire in connector i171, terminal #15 travels to i284/R466 connector, terminal #21
  2. LIME GREEN wire to terminal #12 at R89/D6
  3. LIME GREEN wire to terminal #7 at D80/D81
  4. LIME GREEN wire to terminal #3 at D153 at the PRG auto closer
Call me suspicious, but I think this last BIU wire may be the culprit.
 

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Here is version 0.2 with the updated wires and connectors.
UPDATE
So far the PDF has been viewed 9 times. There will need to be an update to this PDF, hopefully tonight. I will version it accordingly. I really was hoping I was done.

In being asked a question about another fuse, I stumbled upon another circuit which has PRG components, but were not listed in Subaru's PRG system wiring diagram. Here is the update in word form:

FB-22 (LED around the switch)
  1. Power from F/B Fuse #26, WHITE wire w/BLACK stripe to terminal #46 in i282/R464 connector
  2. LIME GREEN wire to terminal #3 at R38/R34 connector
  3. PINK wire to terminal #8 at D155/D156 connector
  4. LIGHT BLUE wire to terminal #3 D154 connector at PRG inner switch
FROM BIU To INNER SWITCH
  1. Starting as BLUE wire w/YELLOW stripe from BIU connector i84, terminal #8 to connector i282/R464 terminal #47
  2. BEIGE wire to terminal #4 at R38/R34 connector
  3. BEIGE wire to terminal #2 at D155/D156 connector
  4. BEIGE wire to terminal #4 at D154 connector PRG Inner switch
Additonal BIU wire
  1. Starting as GREY wire in connector i171, terminal #15 travels to i284/R466 connector, terminal #21
  2. LIME GREEN wire to terminal #12 at R89/D6
  3. LIME GREEN wire to terminal #7 at D80/D81
  4. LIME GREEN wire to terminal #3 at D153 at the PRG auto closer
Call me suspicious, but I think this last BIU wire may be the culprit.

Definitely not in my wheelhouse, but would I be correct in concluding from your posts that control of the PRG is distributed among several fuses, most of which also control other components? And, therefore, that wiring a bypass to a single fuse is not a realistic fix for the battery drain issue?
 

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Discussion Starter · #13 ·
Add a switch to interrupt the power input to the two actuator?!?!
The youtube "solution" involves the carabiner and pulling the #14 fuse. When the tuber re-inserts the #14 fuse, the display shows the rear gate as being closed and the current draw starts to drop. The only system where this makes any sense to me, outside of the PRG CM system, is FB-10: Combination Meter.

Again, I am no genius, but looking at more wiring diagrams, it shows the combination meter gets is power from Fuse #14 when the engine is off and Fuse #15 when ignition is on??? At any rate, the power wire in question is a BEIGE wire, in connector i10, terminal #1 if this is the case.

The Combination meter passes info to the communications system via a BLUE wire in terminal #7 and a RED wire in terminal #6 of the same i10 connector.

If I find out more, I will post more.
 

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At the R214 harness (black wire, 8pin), there's "reference ground" that you might be able to interrupt it with a switch.
1261

1262
 

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Not sure if I'm the YouTuber mentioned above, but here is the link to the workarounds I've found.


You've definitely got a better physical understanding of the wiring and hopefully that'll lead us to a more direct solution or even an automatic one like a relay that triggers or disengages based on whether the vehicle is running or not.

If anyone here is unaware, there's also a facebook group set up to discuss this topic as well: https://www.facebook.com/groups/875597246107705/

Hope this helps!


-Nick
 
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