Battery issues?

[Hobb3s]

Has anyone noticed the battery on their 6th gen fluctuating a-lot while driving? ive noticed my battery meter dropping quite a bit while driving and gradually getting charged.

i also have seen a few error codes around “lost communication” which based on my reading could be due to battery/power issues

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[127.0.0.1]

which battery ?

hybrid battery will go up and down all the time
12v battery should remain stable 12v or higher

in regards to those error codes, what tool did you use ? Use
a proper scan device that is preloaded with 2025/2026 Toyota 4runner data so the
codes will be interpreted correctly.

if the 12v is low and causes any real issues there will be messages in
the dashboard alerting you there is a problem. if it is just your scan tool
reporting codes, [and it is not a techstream], and there are no real
issues you can determine outside that scan tool, ignore it.

 

[Hobb3s]

its the 12v, im on the gas only engine

and used the carista app

 

[127.0.0.1]

Carista does not interpret 6th gen 4runner audio system codes correctly, it is very limited in what it can do.

https://carista.com/en-us/apps/supported-cars/toyota/4runner/6th-gen




Test the voltage when engine is off then when running


BATTERY VOLTAGE (gas only)
Standard voltage:

11 to 14 V

If the voltage is below 11 V, replace or recharge the battery.
------------------
These are DTC's you need to worry about for 12v battery issues

For gasoline model:


The battery state sensor assembly detects the voltage, current and temperature of the battery. The battery state sensor assembly calculates State of Charge (SOC) based on the voltage and current of the battery and sends it to the ECM. Based on the signals received, the ECM adjusts the charging voltage of the generator assembly.

The battery state sensor assembly calculates the battery temperature based on changes in resistance of a built-in thermistor and sends it to the ECM. The ECM reduces the amount of charging current based on this signal in order to protect the battery.

DTC No. Detection Item MIL Warning Indicate DTC Output from Priority Note Link P058A1E Battery Monitor Module Circuit Resistance Out of Range Does not come on Charge warning light does not come on Engine B SAE Code: P058A P058A46 Battery Monitor Module Calibration / Parameter Memory Failure Does not come on Charge warning light does not come on Engine B SAE Code: P058A P058B49 Battery Monitor Module Current Monitoring Performance Internal Electronic Failure Comes on Charge warning light does not come on Engine B SAE Code: P058B P058C01 Battery Monitor Module Temperature Monitoring Performance General Electrical Failure Does not come on Charge warning light does not come on Engine B SAE Code: P058C P058D01 Battery Monitor Module Voltage Monitoring Performance General Electrical Failure Does not come on Charge warning light does not come on Engine B SAE Code: P058D P062049 Generator Control Circuit Internal Electronic Failure Does not come on Charge warning is displayed Engine A SAE Code: P0620 P065C07 Generator "A" Mechanical Performance Mechanical Failure Does not come on Charge warning is displayed Engine A SAE Code: P065C P160200 Deterioration of Battery Low Capacity Does not come on Charge warning light does not come on Engine B SAE Code: P1602 P161A87 Lost Communication with Alternator Missing Message Does not come on Charge warning light does not come on Engine A SAE Code: P161A P162B87 Lost Communication with Battery Monitor Module Missing Message Comes on Charge warning light does not come on Engine A SAE Code: P162B P16E818 Battery Monitor Module Current Monitoring Circuit Current Below Threshold Comes on Charge warning light does not come on Engine B SAE Code: P16EA P16E819 Battery Monitor Module Current Monitoring Circuit Current Above Threshold Comes on Charge warning light does not come on Engine B SAE Code: P16EB P16E81D Battery Monitor Module Current Monitoring Circuit Current Out of Range Comes on Charge warning light does not come on Engine B SAE Code: P16E9

 

[Hobb3s]

just did some monitoring , battery was jumping around 12.5 to 15.1 while running. i reseated the battery connectors and it was at a steady 13.8 after

 

[1stRunner]

Nice job, also overlooked (especially in older vehicles) is a good ground, usually there are multiple grounds, so don't get fixated on checking voltage. Also you need to use the same grnd reference as the module you are testing, not the battery terminal.

 

[Hobb3s]

based on what im reading its part of toyotas smart charging system for batteries

just curious if anyone has seen this on their non hybrid vehicle

it also looks to be a feature for vehicles with ass which the limited does unfortunately

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