Rick's Free Auto Repair Advice

install a car battery

This article provides a tip on how to install a car battery

You can’t just yank the battery cables off a car battery on a late model vehicle. Late model vehicles include many fly-by-wire systems. For example, the accelerator pedal no longer connects to the throttle body with a cable. It’s wired into the PCM and the PCM controls a stepper or servo motor on the throttle body.

image of accelerator postion sensor and electronic throttle body

The gas pedal sends electronic signals to the PCM which then tells the throttle body how far to open

When properly programmed, the PCM knows when the throttle plate is fully closed and fully open. But if you disconnect the old battery without providing supplemental power to the PCM, it can “forget” those settings. Some vehicles will relearn them on their own after a battery change, but others require a scan tool relearn procedure. So install a new car battery y using “old school” methods can actually cost you a tow and a minimum shop fee to put your vehicle through a relearn. Yeah, you may think it’s stupid, but, as they say, welcome to the club.

Here’s how to install a car battery and prevent

Solar ESA30 OBDII Memory Saver Cable

Solar ESA30 OBDII Memory Saver Cable

all those problems. You’ll need a jumper pack or an AC-DC power converter, and you’ll need a special OBDII cable. The SOLAR #ESA30 cable is about $9.

And you can pick up a battery powered jumper pack at any auto parts store or WalMart for under $50. car jumper pack

Plug the cable into the OBDII socket with the key out of the ignition. Then plug the cigarette light end into the jumper pack. Next, disconnect the negative battery cable. Then remove the positive cable and INSULATE it—it’s live. I usually throw it inside a leather glove. THEN you can remove the battery.

Clean the posts on the new and the terminals on the cable. Install the positive cable first and then the negative cable. Make it a quick push-on affair—you want to avoid arcing that can damage computers. Once the new battery is in place, you can remove the supplemental power.

This procedure keeps the PCM fully powered up and prevents it from losing all it “adaptive memory.” So you can start the engine and go without the PCM having to relearn all the values.

change car battery, install car battery

Keep memory alive with a jumper pack and OBDII adapter cable.

It’s the computer age and this is just the way it is. So quit your bitchin about how easy it was in the old days before computers. Remember those days—when you only got 10MPG. Oh yeah, they weren’t really as great as you thought.

Need to charge your car battery? Click here for instructions

If your battery terminals are corroded, replace them. Click here to see how.

© 2012 Rick Muscoplat




Posted on by Rick Muscoplat

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