My 2006 Acura TL with 230,000 kilometres has had the battery replaced twice and the alternator replaced once, yet, the battery is still often dead in the morning. – Irene
When vehicles sit overnight, they go into a sleep mode, which shuts down all electronics except essential memory saving circuits.
Your battery going dead indicates that something is drawing a large current similar to when your headlights are left on accidentally.
Known as parasitic draw test, a technician will use an ammeter placed in series with the battery to aid with the diagnosis. The results are recorded and compared with factory specifications. Most cars will draw approximately 35-50 milliamps while in sleep mode; anything significantly higher indicates a malfunction.
The technician will disable one circuit at a time while monitoring the ammeter until the draw disappears and the faulty circuit is identified. Contenders can be as simple as an always-on interior light bulb such as the one in the trunk, to a shorted alternator diode, or more complex items dealing with failing onboard electrical modules.
Acura TLs and their SUV sibling, the MDX, produced from 2005, have a common problem that I suspect might be your gremlin. The hands-free link system, also known as your Bluetooth receiver, gets stuck in a loop and will stay on permanently, even when the car sits for extended periods, which can draw an additional 250 milliamps.
The simple fix is to permanently unplug the hands-free unit, but if you depend on your Bluetooth, you will have to look at replacing the costly unit.
Lou Trottier is owner-operator of All About Imports in Mississauga. Have a question about maintenance and repair? E-mail globedrive@globeandmail.com, placing "Lou's Garage" in the subject area.
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