Parasitic battery drain (2016 CX-9)

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.
 
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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.
 
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!
 
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.
 
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.
 
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).
 
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.
 
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.
 
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.
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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.
image
image
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.
 
.... 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 (y)(y)
 
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.
 
Update: The parasitic draw returned as described earlier.

This time, I went straight to the PLG buzzer to see if it was the source of the draw and it was. While examining the inside of the PLG, a small beam of sunlight caught my eye. The sunlight was coming through where the wiper motor shaft goes through the PLG. The rubber bushing (Part # TD11-67-407A - retail $9.91) was damaged and allowed water into the PLG. The white padding attached to the back of plastic inside covering was wet.

Clearly, the water had damaged both of my PLG buzzers and was the root cause of my battery drain problems. I have since replaced the bushing and haven't replaced the PLG buzzer. All is working fine and I will replace the PLG buzzer at a later date.

This damaged bushing cost me a lot of money and aggravation. If you own a 2016 Mazda CX-9, check to see if it is damaged. The dealer should have seen this. You can pay all the money in world and it does not guarantee good service.
 
Update: The parasitic draw returned as described earlier.

This time, I went straight to the PLG buzzer to see if it was the source of the draw and it was. While examining the inside of the PLG, a small beam of sunlight caught my eye. The sunlight was coming through where the wiper motor shaft goes through the PLG. The rubber bushing (Part # TD11-67-407A - retail $9.91) was damaged and allowed water into the PLG. The white padding attached to the back of plastic inside covering was wet.

Clearly, the water had damaged both of my PLG buzzers and was the root cause of my battery drain problems. I have since replaced the bushing and haven't replaced the PLG buzzer. All is working fine and I will replace the PLG buzzer at a later date.

This damaged bushing cost me a lot of money and aggravation. If you own a 2016 Mazda CX-9, check to see if it is damaged. The dealer should have seen this. You can pay all the money in world and it does not guarantee good service.
Once again, hats off to you for taking the time to try and help other owners by posting this information (y) (y) (y) These forums don't draw a big audience nowadays in this world of social media, but hopefully your posting will be found by others using search.

And just an FYI that liftgate water damage is definitely not limited to the CX-9. Here's a TSB for the CX-5, which describes some proactive waterproofing that Mazda came up with to help address this issue. I don't know how much of it would apply to the CX-9, but I'd expect that the connector waterproofing technique might at least be similar. Not too much of a job to get this completed, and I recommend that any DIYer reading this consider doing it. No idea what a dealership would charge to do it out of warranty.
 
The TSB talks about using PVC tape, which I generally think of as "common cheap electrical tape".

If I had this issue I'd probably use self-sealing silicone tape. This is an example (many sources for it exist): https://www.amazon.com/dp/ (commissions earned)

The silicone tape is rated for -50 to 500F, tensile strength of 900 PSI, great for lots of odds and ends repairs. I use it frequently on hoses/connectors, great for lots of DIY fixes around the house.
 
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The TSB talks about using PVC tape, which I generally think of as "common cheap electrical tape".

If I had this issue I'd probably use self-sealing silicone tape (what I use for things like underground wiring, other sealing where I want real waterproofing and long-term environmental durability). This is an example (many sources for it exist): https://www.amazon.com/dp/ (commissions earned)
Yes, good you mentioned that. I did the work a while back, and didn't even remember that I substituted (a different brand) 20 mil silicone tape for their PVC spec in the TSB. A bit more $$, but definitely a better choice.
 
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Thanks for the responses regarding the TSB and the tape. That is good information. The liftgate switch appears to be exactly the same on my CX-9. I am attaching two pics of the PLG buzzer so it is easier to identify.
 

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So the incompetent "technicians" at the dealership failed to fix the problem and charged you $1,100. The problem was the water leak; the symptom was the wet & grounded buzzer. What else have they overcharged you for? I haven't heard of any problems in the Gen 2 PTU...do these cars have a power transfer unit, and there is no part listing by that name on the parts list. Would this be the all wheel drive coupling unit, the clutch assembly ahead of the rear differential? I haven't heard of any failures there and two on the same car sounds like technician error.

My state has an auto repair complaint center, part of the Attorney General's Office. Among the violations of this state law is, "Charging the customer for repairs for which there is no reasonable basis," which seems to fit your situation. Among the valid complaints are, "Authorized repairs proved inadequate to repair car," and, "The customer is not satisfied with the vehicle after the repair." You can check what resources you have where you live. It might be time (past time) to schedule a sit-down discussion with the service manager (not just one of the service writers) with all your seemingly excessive repair documents and talk about refunding much of your money before you take an action under the law where you live. Be firm, be concise, be business-courteous, and demand fair treatment.
 
Lack of actually fixing the failure condition.

What they did was replace the parts failed due to the water leakage, without taking the action to fix the leakage (that the replacement PLG also failed is the proof of their not correcting the actual failure mode). A competent shop would have done a basic check for info on the source of leakage killing those items.

Curious on if the liftgate opener switch itself was actually failed too, and, if so, whether it also showed corrosion. If they both showed corrosion, and the tech didn't do a "where's the water coming from?"

A serious chat with the manager should be held. (Serious being a hefty refund, and, most likely, a complaint to Mazda USA. ).

Checking in with your state consumer affairs division to see if they have rules similar to PTguy's state, also makes sense. I'd do that after giving the Mazda shop a chance to make good.
 
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Lack of actually fixing the failure condition.

What they did was replace the parts failed due to the water leakage, without taking the action to fix the leakage (that the replacement PLG also failed is the proof of their not correcting the actual failure mode). A competent shop would have done a basic check for info on the source of leakage killing those items.

Curious on if the liftgate opener switch itself was actually failed too, and, if so, whether it also showed corrosion. If they both showed corrosion, and the tech didn't do a "where's the water coming from?"

A serious chat with the manager should be held. (Serious being a hefty refund, and, most likely, a complaint to Mazda USA. ).

Checking in with your state consumer affairs division to see if they have rules similar to PTguy's state, also makes sense. I'd do that after giving the Mazda shop a chance to make good.

Lack of actually fixing the failure condition.

What they did was replace the parts failed due to the water leakage, without taking the action to fix the leakage (that the replacement PLG also failed is the proof of their not correcting the actual failure mode). A competent shop would have done a basic check for info on the source of leakage killing those items.

Curious on if the liftgate opener switch itself was actually failed too, and, if so, whether it also showed corrosion. If they both showed corrosion, and the tech didn't do a "where's the water coming from?"

A serious chat with the manager should be held. (Serious being a hefty refund, and, most likely, a complaint to Mazda USA. ).

Checking in with your state consumer affairs division to see if they have rules similar to PTguy's state, also makes sense. I'd do that after giving the Mazda shop a chance to make good.

So the incompetent "technicians" at the dealership failed to fix the problem and charged you $1,100. The problem was the water leak; the symptom was the wet & grounded buzzer. What else have they overcharged you for? I haven't heard of any problems in the Gen 2 PTU...do these cars have a power transfer unit, and there is no part listing by that name on the parts list. Would this be the all wheel drive coupling unit, the clutch assembly ahead of the rear differential? I haven't heard of any failures there and two on the same car sounds like technician error.

My state has an auto repair complaint center, part of the Attorney General's Office. Among the violations of this state law is, "Charging the customer for repairs for which there is no reasonable basis," which seems to fit your situation. Among the valid complaints are, "Authorized repairs proved inadequate to repair car," and, "The customer is not satisfied with the vehicle after the repair." You can check what resources you have where you live. It might be time (past time) to schedule a sit-down discussion with the service manager (not just one of the service writers) with all your seemingly excessive repair documents and talk about refunding much of your money before you take an action under the law where you live. Be firm, be concise, be business-courteous, and demand fair treatment.
Since the original repair is over 6 months old, it would be impossible for me to prove that the water leak was root cause. Even if I could get them to cover the PLG buzzer at this point, it is not worth my time. What is worth my time is spreading the word to potentially help someone else experiencing the same problem.
I don't think the technicians are totally incompetent. In my case they figured out what happened but not why it happened. Time is money, nobody will look at your car the way you do.

The part # for PTU is (KN01-27-500A) KN01-27-500A - Transfer - Genuine Mazda Part
Mine was replaced twice under warranty. The problem was the seals leaking.

You will also be happy to know that I have not been overcharged for anything else. The dealer is the last resort for me.
 
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