Post-Dead Battery Issues
Thread Starter
Driver School Candidate
Joined: Sep 2016
Posts: 6
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From: California
Post-Dead Battery Issues
I just replaced the totally dead battery in my 2012 RX-350 using the "second parallel battery" technique that usually preserves codes, settings, etc. I think the old battery was totally dead since with the new battery installed I am getting a few weird warnings, codes, etc. (e.g., TRAC Off and Malfunction Indicator Light/Engine Check Light On) -- plus the usual need to reset the radio pre-sets, seat positions, back power door, etc. that are usually associated with an open battery circuit. The car starts and runs fine with the new battery.
The Manual says to take the car to the Lexus dealer ($$$) to have them address/reset the TRAC Off and Malfunction Indicator Light/Engine Check Light On functions. Is this really necessary or will these functions reset themselves over time or can I do it?
Many thanks!
The Manual says to take the car to the Lexus dealer ($$$) to have them address/reset the TRAC Off and Malfunction Indicator Light/Engine Check Light On functions. Is this really necessary or will these functions reset themselves over time or can I do it?
Many thanks!
CL Community Team
Joined: May 2005
Posts: 7,150
Likes: 1,711
From: VA
You may have to clear the codes. Many chain auto parts stores will do this for you. Then drive a few days and if all stays clear you will be okay.
Or they may just clear themselves in a few days.
IF they persist:then an independent Toyota or Japanese car specialist can handle this problem. You do not need the dealer.
Or they may just clear themselves in a few days.
IF they persist:then an independent Toyota or Japanese car specialist can handle this problem. You do not need the dealer.
CL Community Team
Joined: Apr 2001
Posts: 16,533
Likes: 1,379
From: Austin, TX
If you have lost your presets, might as well disconnect the newly installed battery for about 20 (guess) minutes and then reconnect.
When you have low voltage condition the sensor outputs are not correct and the ecu can also lock random conditions. When you disconnect for enough time, the ecu gets reset [can be done by a cheap obdII reader too].
For the same reasons I do not recommend side supply when the battery is dead.
Salim
When you have low voltage condition the sensor outputs are not correct and the ecu can also lock random conditions. When you disconnect for enough time, the ecu gets reset [can be done by a cheap obdII reader too].
For the same reasons I do not recommend side supply when the battery is dead.
Salim
Thread Starter
Driver School Candidate
Joined: Sep 2016
Posts: 6
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From: California
Thanks, guys! By the third short trip around town my codes appear to have cleared all by themselves (i.e., TRAC is working normally and the constant Malfunction Indicator Light/Engine Check Light has disappeared). All is good -- thanks again.
ps -- The former 7-year-old OEM battery suddenly dropped to @ 10.4 volts and would not accept any charge -- I'm guessing a failed cell. Can't complain, seven years is pretty good service for a car battery these days. I think Salim was correct in diagnosing a low-voltage condition impacting the ECU codes.
ps -- The former 7-year-old OEM battery suddenly dropped to @ 10.4 volts and would not accept any charge -- I'm guessing a failed cell. Can't complain, seven years is pretty good service for a car battery these days. I think Salim was correct in diagnosing a low-voltage condition impacting the ECU codes.
Last edited by DHeal; Aug 25, 2019 at 06:16 PM.
Racer
Joined: May 2006
Posts: 1,987
Likes: 599
From: NC
I am surprised you got seven years out of your factory battery - they are mediocre at best. My wife's 2015 model's factory battery failed in February 2018 while the vehicle still belonged to its original owner in Florida. We purchased the vehicle here in North Carolina in late October 2018 and the battery is certainly on my watch list. The four-year / 50,000-mile Lexus basic warranty on the vehicle expired last Wednesday. Sure hope the rear shocks hold up and do not begin leaking.
Pit Crew
Joined: Nov 2018
Posts: 117
Likes: 11
From: SK
I'll add another datapoint. My battery got drained while experimenting with towing equipment and leaving lights on.
Had those codes set for like 4 days. Then they disappeared.
Hopefully this datapoint helps anyone else who experiences the same thing.
Had those codes set for like 4 days. Then they disappeared.
Hopefully this datapoint helps anyone else who experiences the same thing.
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Mike234588
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Sep 11, 2016 11:27 PM
