Lexus ES Battery Alarm

Alright, I'm pulling my hair out here! My 2020 Lexus ES with a gasoline engine is throwing a weird battery alarm. The error memory's showing something, and the alarm system's totally dead. Could the aux battery be the culprit? I can't think of what else it could be!

4 comment(s)

Sounds like a discharged auxiliary battery is the most likely suspect, especially given the age of the car. Has the battery ever been replaced? These Lexus systems can be finicky when the voltage drops too low. A multimeter check could confirm your suspicions.

I don't think it has ever been replaced. Where exactly is the auxiliary battery located in the ES? And what voltage am I looking for on the multimeter?

On your ES, the auxiliary battery is usually near the main battery. You're looking for a voltage reading below 12.6V. A weakened battery will trigger the alarm system failure. It's probably best to get it checked by a shop, since you'll need to recode the system, too.

Thanks a ton for the help! Turns out the battery was knackered after all. Ended up costing me 330€ to have a shop replace it and clear the error codes, but at least the car alarm is working again!

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