Parasitic battery drain (2016 CX-9)

[cwd191161@g]

Hello, I am new to the forum.

Vehicle : 2016 CX-9 Grand Touring

Problem: Parasitic battery drain of 1.25 amps is consistent while in sleep mode. Drains good battery in 2 days.

I have isolated it to the Interior 10 amp fuse # 39. When I remove the fuse, amperage draw will drop to 0 in approximately 1 minute.
Using AllData to view the wiring schematics, but this circuit is covering a wide range of electronics. I am trying to systematically rule out all of the components on the circuit. If anyone has had the same experience, I would really appreciate to know how you resolved it.

Other steps taken:
1) Confirmed good battery with 2 different analyzers.
2) Used a different battery - same draw
3) Alternator charging at 14 volts.
4) Disconnected alternator power and wiring harness to verify that it is not the source of the draw.
5) Using multimeter in series on negative of battery to measure the draw.
6) Making sure door locks and hood latch are manually locked and getting the one honk when arming the alarm.
7) Waiting at least 40 minutes for sleep mode.

 

[edmaz]

....
I have isolated it to the Interior 10 amp fuse # 39. When I remove the fuse, amperage draw will drop to 0 in approximately 1 minute.
....

I'm not familiar with your vehicle, and don't have a wiring diagram for it, so I can't give you any advice on the circuits. However, I will ask if you actually did see a reading of 0 amps on the meter, after pulling the 39 fuse. If so, then you might not have the actual culprit fuse identified, because there should always be somewhere around a .03A reading, with all of the computers in sleep mode. A true 0 amp reading means all of the computers shut down completely, which should never happen in normal operating mode.

 

[cwd191161@g]

Thanks for responding...that puzzled me as well. Supposed to be 10 - 30 milliamps in sleep mode. I just don't know how much of that draw comes through that circuit. I will check that again... thanks!

 

[edmaz]

I suspect that the 39 fuse protects one or more primary supply voltage circuits to the PCM, and when it's pulled, the computer conducts an orderly shutdown. And if that's true, that shutdown might have fooled you into thinking that you found the culprit fuse. Not saying that #39 isn't where the issue is, only that it's not clear at this point.

Was every other fuse pulled as well, or did you stop pulling them once you saw the result from 39? If you didn't pull all of them, you might want to start the draw testing up again and check the ones you haven't done yet.

 

[PTguy]

I've heard of continuous drains from the lift gate toe-wave device and from the rear window defroster being always on due to a stuck relay. On that wiring schematic, on the circuit in question, which non-essential devices can you unplug and then check the current draw? Your multimeter connected in series is a more accurate method for small draws than a clamp on ammeter. Let us know what you eventually find.

 

[youri]

i believe that was on 2019 or 2020 model year. See that post:
Post in thread 'Battery drain in 2020 Mazdas'
https://mazdas247.com/forum/t/battery-drain-in-2020-mazdas.123872557/post-6694492

The interesting thing in that testing procedure is that you should wait 40 minutes after the car shut off before testing for parasitic draw. Before the 40 minute mark, as mentioned above it is normal to have amperage reading. (And even after if it is below the value indicated in the TSB).

 

[cwd191161@g]

I want to thank all of you for responding. The voltage dropped to an average of .03 amps when pulling that fuse. I should have been clearer on that. I did check every fuse and relay multiple times. Had to break down and bring it to the dealer. When I have the resolution to this, I will definitely post it.

 

[cwd191161@g]

I want to thank all of you for responding. The voltage dropped to an average of .03 amps when pulling that fuse. I should have been clearer on that. I did check every fuse and relay multiple times. Had to break down and bring it to the dealer. When I have the resolution to this, I will definitely post it.

 

[cwd191161@g]

According to my local Mazda dealer, the source of the parasitic draw was:

1) PLG Buzzer (part # TK49-62-6J0B)

2) Liftgate Opener Switch (part # GHP9-62-4B)

I verified the repair and I no longer have the parasitic draw. It cost nearly $1100 to have this repaired. I hope it helps somebody.

This is also my first and last Mazda. It's just too problematic. The PTU and infotainment display have both been replaced twice already.

The power liftgate (PLG) buzzer is located inside the liftgate lower trim.

ac9uun00001620

 

[Jack Rabbit]

According to my local Mazda dealer, the source of the parasitic draw was:
1) PLG Buzzer (part # TK49-62-6J0B)
2) Liftgate Opener Switch (part # GHP9-62-4B)

I verified the repair and I no longer have the parasitic draw. It cost nearly $1100 to have this repaired. I hope it helps somebody.

This is also my first and last Mazda. It's just too problematic. The PTU and infotainment display have both been replaced twice already.





The power liftgate (PLG) buzzer is located inside the liftgate lower trim.

ac9uun00001620

Glad you got it fixed. Agree with you. I love the CX-5, love the safety features and love how it drives but dont know if i can afford repairs. It's already got intermittent lifters tapping at 36,000 miles and others have had cracked cylinder heads. At least the lifters noise is not occuring now that it's warmer out. But, after owing multiple vehicles, Ford, Toyota, VWs that lasted well over 10 years/150,000 miles before any problems, the mazda CX series is starting to worry me.

 

[edmaz]

.... It cost nearly $1100 to have this repaired. ....

Considering that the total cost of those 2 parts is under $200 retail, what they charged you for that work is IMO off-the-wall (but also sadly not surprising or unusual). They proudly earned their stealership name, and let's just say you did your part to help pay for their new boats.

But on the plus side, thanks for trying to help others by following up with the resolution to your problem

 

[cwd191161@g]

I have been reflecting on how I was unable to figure out where parasitic draw was and how will approach it next time.

I discounted the PLG because it was working fine and not kicking any DTC's after using it. In fact all of the modules were scanning good (approximately 24) with my scan tool. When I removed the PLG fuse, there was no change in the parasitic draw. Note: I did have to change the PLG module in the Fall of last year because the Liftgate was going up and down by itself. The problem was resolved after changing the module.

I had removed both of the interior panels on the right and left of the vehicle which provided access to the modules and wiring. I removed enough of the panel in the liftgate to disconnect the actuator which closed the trunk. There was no change in the draw when I disconnected the actuator or either liftgate motor. I had made an assumption that the liftgate was not a problem after that.

Next time, I will remove all of the coverings and look more for heat. Considering how much of draw there was, the defective part must have been heating up and I wasn't really thinking of that.