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Drive unit or battery problem?

Nick70d

Member
Jan 20, 2019
133
65
St.louis
1. Code: i_w172_SW-Drive_iso Car needs service, May not restart
2.Code: BMS_u008 Acceleration and top speed reduced, performance may be restored on next drive
Car still driveable , regen loss.
 

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maximizese

Member
Jan 16, 2018
464
435
California
I had the same issue on our November 2013 build S85 back in December 2019 but with the added warning message of "Regenerative braking system disabled." I called Tesla Roadside and they instructed me to drive to my local Service Center before attempting a reboot (so the car wouldn't have to be towed if it failed to restart). The car did restart, but the issues remained. A quick diagnostic of the logs showed the need to replace the HV contactors. They also replaced the HVAC drain hose, 12V battery, and drive unit while there at it (whining rotational noise was getting pretty bad over the last 3 months).

I have an Anker ROAV 12V battery monitor and it showed no signs of a worn 12V battery, but I'm assuming a failing HV contactor might have placed more strain/stress on the 12V thus the replacement...that or Tesla was checking all the boxes to make sure I wouldn't be back soon after.
 
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maximizese

Member
Jan 16, 2018
464
435
California
Certainly. I use this in all of our cars to test the battery voltage every month before starting the car. You'll want to test before starting as the alternator/HV contactors will replenish the 12V battery during a drive. I found this a very helpful determining when to replace the 12V before getting stranded. Our old 2007 Lexus Rx400h would go through 12V batteries every 2 years and the only warning was the power windows started moving slowly about a week before failure.

Apparently the Tesla and our Fiat 500e has a warning message when the 12V battery starts to fade, but I'd like to be made aware before the warning message appears.

https://www.amazon.com/Roav-SmartCh...ry+monitor&qid=1583174696&s=automotive&sr=1-4

51sgwmdy-jL._AC_.jpg
 
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Jcastillo18

Member
Mar 27, 2020
5
3
Texas
Same thing happened to me . Acceleration is reduce and regeneration breaking was disabled and see service station soon . Is it stage to drive the car ? It’s. 2016 Model S 70D
 

Doanster1

Member
Feb 14, 2018
876
463
Oregon
Mine was also replaced about a month ago (P85D). In my case, though, remote viewing of the logs clearly showed a fault with the Battery Coolant Heater, so I’m surprised they couldn’t diagnose tots until they had it in at the SC. Either way, glad to hear you’re back on the road and it was covered under warranty.
 

Xenoilphobe

Active Member
Jan 2, 2014
4,578
4,283
Fairfax County, Virginia
Mine was also replaced about a month ago (P85D). In my case, though, remote viewing of the logs clearly showed a fault with the Battery Coolant Heater, so I’m surprised they couldn’t diagnose tots until they had it in at the SC. Either way, glad to hear you’re back on the road and it was covered under warranty.
They need to add a temperature gauge for the battery. Kinda old school, but it would be cool to watch while driving.
 
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RealtorinMiami

New Member
May 31, 2020
1
1
Miami Beach
I am having the same error message and my car was okay for about 3 days and now the battery is dead. I also had a software update and it did not reset anything. I am going to have to go to service center. Just trying to figure out what to expect.
 
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evbeliever

Member
Apr 6, 2016
17
8
NJ
Had the same error message. 2016 MS 70 85k miles. Car was in service for about 2 weeks and they say they replaced the Large Rear Drive unit under warranty.

my only question is the parts ordered show a lot of items but not the specific Drive Motor Unit as a part.

Our new service center in Princeton, NJ did a good job though and kept me updated.
 
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