2020 CX-5 mysterious battery draw

Hi,
New member here looking for some insights into a mysterious electrical draw that’s causing my battery to go dead overnight on a new 2020 CX 5 Signature. It seems to happen when I pull the car into the garage at night. No lights or accessories are left on, nothing, such as charger, is plugged in and the car is turned completely off not left in accessories mode. The car has been at the dealer for a week. They couldn’t find any abnormal electrical draw and the battery was in normal condition. Apparently the 2020s have some type of wifi modem for future functionality and the service manager thought it might be seeing my house WiFi (recently installed a new / stronger house WiFi router) but they checked and the device on the CX 5 is in the correct inactive mode. They were telling me they couldn’t find anything. I pressed them to keep looking and then they found a recent service bulletin about a potential issue with a rear left gate electronic that might draw more power than normal when the car is off but they were talking miliamps and I am uncertain that extra amount is enough to drain the battery overnight. The left gate electronic part is on back order. I also asked the dealer to test parking it with objects in front and behind to assess whether the parking sensors are staying active after it’s turned off. It’s been a big downer on a new top of the line Signature we spent $40k on. Anyone heard of this type of issue and what the solution might be? Thanks guys.
 
You have a parasitic draw. Finding the source of a parasitic draw (once obvious sources are ruled out) is a very time consuming process, involving testing each and every fuse separately to identify which circuits are the source of the draw. once the circuit is identified, that's just the start, as you need to see what is connected to that circuit.

From the sounds of it, your dealer did not go through the time consuming process of identifying exactly what circuit is causing the draw, and is just guessing based on things like a TSB that a rear lift gate "could" be the issue.

Here's an old video explaining how to find the source of a parasitic draw.
The video is old, and there are some improved methods now (where you don't actually have to pull each and every fuse). But the basics are the same.
 
:
2019 CX5 Reserve AWD
I would push the dealer to replace the battery with a new one and see what happens after.
Even though the battery tests normal that doesn't preclude some problem with the battery.
There's plenty of posts about people having problems with their batteries even though they test fine.
 
:
Vancouver Canada
:
2020 GT Turbo
I've have the same problem with my 2 month old 2020 GT Turbo going completely dead a couple of times while parked for a day or so. Had it jump started and took to the dealer. Dealer couldn't find anything wrong. Even left it for a few days at the dealer to see if it happened again. But of course not. Dealer checked battery and alternator, etc. Nothing plugged in but a USB stick for music. Dealer said maybe it was the result of leaving a USB plugged in but I presume that all power shuts off when the car shuts down. The USB was plugged in for almost 2 months with no issues before the second failure. Now I don't leave it in. Hopefully a new battery might solve the issue if it happens again. Very annoying for a new vehicle.
 
I would check the Lemon law for your state. If it keeps happening to a 2020 mand they can't fix it, I would assume the car would fall under the law.
 
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40752

I would be curious what the parasitic draw is when (or if ) they tested it at the battery connection. I don’t know what the Mazda spec is but that would be the starting point. There will always be some draw there when car is turned off but probably not more than 100 milliamps or so. Was this problem happening every night?
 
Hi guys, I’m the original poster. Thanks for the earlier replies especially those from multimut and wlong01. Much appreciated. I just got my 2020 CX 5 Signature back after nearly 2 weeks. Multimut - I did press the dealer to go through a circuit by circuit process to try to find the parasitic draw. They didn’t check every car circuit but they did for numerous ones suggested by a Mazda regional service specialist to whom they elevated the issue. They could not find the problem but they believe me and tried to. I’m not alone, another owner also brought in his 2020 CX 5 to my dealer with the exact same issue of the battery mysteriously going dead. With the other replies to my post clearly Mazda has an parasitic draw issue affecting multiple cars. The dealer did replace the rear lift gate control module that a TSB said could be causing an excessive draw when the car is off / goes to sleep. (Part no. KBG6626H0C/1) Wlong01 - I took your suggestion and pressed on them replacing the battery, got them to admit that the battery capacity would have been permanently reduced by it (was brand new) going completely dead twice. They replaced the battery. On the service receipt the noted, “battery failed load test and is required to be replaced at this time.” Now that may have been just to document why they gave me a replacement battery since the told me verbally earlier that my battery tested perfect. Whatever, if the battery had a short (such things do happen) that’s now a problem I don’t have to worry about. Costs for the control module, battery and labor were borne by the dealer or Mazda, my only cost was the inconvenience and not having the car for 2 weeks. I’ll keep you guys posted on how things go. Thanks.
 
I would be curious what the parasitic draw is when (or if ) they tested it at the battery connection. I don’t know what the Mazda spec is but that would be the starting point. There will always be some draw there when car is turned off but probably not more than 100 milliamps or so. Was this problem happening every night?
JT2 - Thanks for your questions. Yes there is always a draw when these cars are off / go to sleep. Some guy at the dealer told me on a CX 5 it should be 6 mA (milliamperes) or less. Not sure he was right. I got the car at the end of February and the problem didn’t show up until early April. At the time I was starting to park it in the garage at night vs leaving it in the driveway. I heard a beep come from the rear lift gate area after I turned the car off when I closed the garage door. That made me think that a rear sensor was remaining active even though the car was off and going to sleep. See my other reply about the dealer replacing the rear lift gate sensor.
 
:
2020 CX-5 GTR
This just happened to my car this morning. Very annoying - never thought i'd have to use my emergency battery pack to jumpstart a brand new car. @Trygg please keep us posted on if the new part fixed the issue.
 
:
Ottawa, Ontario
:
17 Mazda 6 GT
I know it's a different make, but if I recall correctly, Honda CR-V's have experienced the same problem.
Might be worthwhile spending a few minutes googling their problems.
Maybe Mazda has the same issue.
 
This just happened to my car this morning. Very annoying - never thought i'd have to use my emergency battery pack to jumpstart a brand new car. @Trygg please keep us posted on if the new part fixed the issue.
Sorry to hear that it happened to you too. It’s been six days since Mazda replaced the rear lift gate control module (see my earlier post for part number) and the car battery and so far so good. The car has been parked the same way it was when the parasitic draw / dead battery issue first occurred. I’d suggest letting your dealer know that there’s a TSB out advising that the rear lift gate control module can cause excessive draw when the car is off. You may need to ask the dealer to elevate it to Mazda regional level as they aren’t advertising that this issue is out there. Since you jumped your car I suggest you or your dealer charge your battery with a smart charger rather then rely on your alternator. Alternators are designed to maintain battery level, not to fully charge them. Using an alternator to do so puts more stress on it. Good luck with your dealer. Push them to elevate it if it’s a repeating problem.
 
:
Vancouver Canada
:
2020 GT Turbo
Thanks for posting your information on this issue. My 2020 CX 5 has failed twice after being parked for a day or so and this TSB about the rear lift gate control module will be very good information to present to the dealer if it happens again. Do you by any chance have the TSB number?
 
Sorry to hear that it happened to you too. It’s been six days since Mazda replaced the rear lift gate control module (see my earlier post for part number) and the car battery and so far so good. The car has been parked the same way it was when the parasitic draw / dead battery issue first occurred. I’d suggest letting your dealer know that there’s a TSB out advising that the rear lift gate control module can cause excessive draw when the car is off. You may need to ask the dealer to elevate it to Mazda regional level as they aren’t advertising that this issue is out there. Since you jumped your car I suggest you or your dealer charge your battery with a smart charger rather then rely on your alternator. Alternators are designed to maintain battery level, not to fully charge them. Using an alternator to do so puts more stress on it. Good luck with your dealer. Push them to elevate it if it’s a repeating problem.
Trygg - Do you have a copy of the TBS on lift gate? My new CX5 is having the same issue and Dealer cannot find anything! My vehicle has less then 500 miles. Very disappointed
 
My new CX5 that has under 500 miles has been brought back to dealer for the third time with a dead battery. Very Disappoined!! Dealer can not find anything wrong and is telling me they are performing this Parasitic testing and still not able to find anything. Has anyone found anything to be causing this? Does anyone have the TSB with the tail gate? Thanks!!
 
Hey guys, here’s the exact info from the Mazda warranty service receipt:
“Cause - NO DRAWS FOUND ON SYSTEM DURING INITIAL INSPECTION. CALLED TECH LINE. WAS REFERRED TO REPLACE POWER LIFTGATE CONTROL MODULE.”

“Correction - REPLACED MODULE PER MAZDA TECH SUPPORT S1219DRD/.4 S64 D9W KBG6626H0C/1“

The control unit part is KBG6626H0C
So if you have this issue I suggest you press your dealers to call Mazda tech support. I’m in central Connecticut so the tech support guy for the NorthEast has this figured out. Good luck. Eight days since I got my CX 5 Signature back and battery is operating normally.
 
Hey guys, here’s the exact info from the Mazda warranty service receipt:
“Cause - NO DRAWS FOUND ON SYSTEM DURING INITIAL INSPECTION. CALLED TECH LINE. WAS REFERRED TO REPLACE POWER LIFTGATE CONTROL MODULE.”

“Correction - REPLACED MODULE PER MAZDA TECH SUPPORT S1219DRD/.4 S64 D9W KBG6626H0C/1“

The control unit part is KBG6626H0C
So if you have this issue I suggest you press your dealers to call Mazda tech support. I’m in central Connecticut so the tech support guy for the NorthEast has this figured out. Good luck. Eight days since I got my CX 5 Signature back and battery is operating normally.
Trygg, thank you for responding back.....I will be informing my Mazda Service manager on your reply. I know my Service manager spoke with Corporate already about my issue and they informed them they have not heard of any other issues reported on mysterious battery issue. Since I am also in the NorthEast (NJ) Would it be possible to let me know the name of your Mazda dealers name and location in Central CT, so I can have my service manager contact them as well as the Northeast reg manager? If you have any other information that you would be able to provide, it would be most appreicated. - THANKS
 
Trygg, thank you for responding back.....I will be informing my Mazda Service manager on your reply. I know my Service manager spoke with Corporate already about my issue and they informed them they have not heard of any other issues reported on mysterious battery issue. Since I am also in the NorthEast (NJ) Would it be possible to let me know the name of your Mazda dealers name and location in Central CT, so I can have my service manager contact them as well as the Northeast reg manager? If you have any other information that you would be able to provide, it would be most appreicated. - THANKS
FrankGas, my dealer is Mazda of Manchester in Manchester CT, smaller family owned dealer and very service oriented. Service manager there is Jeff, great guy with a low key style who stuck with me and was willing to elevate it when they couldn’t figure it out locally.
 
FrankGas, my dealer is Mazda of Manchester in Manchester CT, smaller family owned dealer and very service oriented. Service manager there is Jeff, great guy with a low key style who stuck with me and was willing to elevate it when they couldn’t figure it out locally.
Great - THANK YOU!!
 
:
Texas
:
'20 CX-5 Signature
Trygg - Do you have a copy of the TBS on lift gate? My new CX5 is having the same issue and Dealer cannot find anything! My vehicle has less then 500 miles. Very disappointed
Here you go...

The TSB simply refers dealers to call Mazda if a 2020 CX-5 or 2019-2020 CX-9 with the power liftgate won't start due to a low battery.
 

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