My wife's 2001 ES300 has had a slow battery drain that results in a low battery charge and inability for the car to start after several days of not being driven. I first charged the battery to 12.7 volts with a battery charger, I checked the alternator and found charging at 14. 4 volts and took the battery to Pep Boys to conduct a load test and battery condition after 1.5 hour charge. Battery checked out in good condition. I then proceeded to finding what was causing the battery drain. Using a multimeter set on "amps" I removed the ground connector from the battery and hooked one multimeter lead to the battery and the other lead to the disconnected battery ground cable connector. After 3-5 min. with the ground strap disconnected, I took a reading of the battery drain. The multimeter showed a 150 ma current drain. At that point I started pulling fuses to see which would stop the drain. When I pulled the 10a ECU-B fuse the drain immediately dropped to 20ma. The question I have is what devices/circuits receive power through the ECU-B fuse? Second, what further steps can I take to determine what device/circuit fed from this fuse are drawing current with the key off and the car sitting idle?
Slow Battery Drain
in 92 - 06 Lexus ES250/300/330
Posted
My wife's 2001 ES300 has had a slow battery drain that results in a low battery charge and inability for the car to start after several days of not being driven. I first charged the battery to 12.7 volts with a battery charger, I checked the alternator and found charging at 14. 4 volts and took the battery to Pep Boys to conduct a load test and battery condition after 1.5 hour charge. Battery checked out in good condition. I then proceeded to finding what was causing the battery drain. Using a multimeter set on "amps" I removed the ground connector from the battery and hooked one multimeter lead to the battery and the other lead to the disconnected battery ground cable connector. After 3-5 min. with the ground strap disconnected, I took a reading of the battery drain. The multimeter showed a 150 ma current drain. At that point I started pulling fuses to see which would stop the drain. When I pulled the 10a ECU-B fuse the drain immediately dropped to 20ma. The question I have is what devices/circuits receive power through the ECU-B fuse? Second, what further steps can I take to determine what device/circuit fed from this fuse are drawing current with the key off and the car sitting idle?