🔧 CX-5 - 12V Battery Replacement

This repair replaces the 12-volt starting battery in your CX-5. A weak battery can cause slow cranking, warning lights, i-ACTIVSENSE messages, keyless-entry problems, and stop/start system issues.

Difficulty Level: Beginner | Estimated Time: 20-40 minutes

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⚠️ Safety & Precautions

• ⚠️ Wear safety glasses and gloves. Battery acid can burn skin and eyes.
• ⚠️ Do not let tools touch both battery terminals at the same time. This can cause sparks or a short circuit.
• ⚠️ Always remove the negative cable first and install it last.
• ⚠️ Keep flames, cigarettes, and sparks away from the battery area.
• ⚠️ Your CX-5 has battery monitoring and electronic modules. A memory saver helps preserve settings, but the battery can still be changed without one.
• ⚠️ Disconnecting the battery may reset auto window, clock, and infotainment settings.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 10mm wrench
• Ratchet handle 3/8-inch drive
• Socket extension 6-inch 3/8-inch drive
• Battery terminal puller (specialty)
• Battery terminal cleaning brush
• Battery carrier strap
• Memory saver 12V OBD-II (specialty)
• Torque wrench inch-pound 3/8-inch drive
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V AGM battery Group Size 35 - Qty: 1
• Battery terminal protector spray - Qty: 1
• Battery anti-corrosion felt washers - Qty: 2

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📋 Before You Begin

• Park your CX-5 on level ground, shift to Park, and apply the parking brake.
• Turn the ignition OFF and keep the key fob at least 15 feet away from the vehicle.
• Open the hood and support it fully.
• If using a memory saver, plug it into the OBD-II port under the driver-side dashboard before disconnecting the battery. A memory saver is a small backup power supply that helps keep radio, window, and module memory alive.
• Wait at least 3 minutes after turning the ignition OFF before disconnecting the battery so vehicle modules can go to sleep.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Locate the Battery

• Open the hood and look at the front-left area of the engine bay.
• Use safety glasses and nitrile gloves before touching the battery.
• Identify the negative terminal marked - and the positive terminal marked +.
• Take a photo before removal.

Step 2: Remove the Negative Battery Cable

• Use a 10mm wrench or 10mm socket to loosen the negative terminal clamp nut.
• Twist the clamp gently and lift it off the negative battery post.
• If it is stuck, use a battery terminal puller. A terminal puller lifts the clamp without damaging the battery post.
• Move the negative cable aside so it cannot spring back and touch the battery post.

Step 3: Remove the Positive Battery Cable

• Lift the red plastic cover from the positive terminal.
• Use a 10mm wrench or 10mm socket to loosen the positive terminal clamp nut.
• Lift the positive cable off the battery post and move it aside.
• Do not let the positive cable touch metal body parts.

Step 4: Remove the Battery Hold-Down Bracket

• Use a 10mm socket, ratchet handle 3/8-inch drive, and socket extension 6-inch 3/8-inch drive to loosen the battery hold-down fasteners.
• Remove the upper hold-down bracket and set it aside.
• Keep the bracket and hardware together so nothing gets lost.

Step 5: Remove the Old Battery

• Attach a battery carrier strap to the battery if available.
• Lift the battery straight up and out of the tray using both hands.
• The battery is heavy. Keep your back straight and lift with your legs.
• Set the old battery upright on cardboard or a safe flat surface.

Step 6: Clean the Battery Tray and Cable Ends

• Use a battery terminal cleaning brush to clean the inside of both cable clamps.
• Use the same battery terminal cleaning brush to clean any light corrosion from the tray area.
• If there is white or blue powdery corrosion, avoid breathing the dust and wipe it carefully with a damp disposable cloth.
• Clean terminals help prevent no-starts.

Step 7: Install the New Battery

• Place the new 12V AGM battery Group Size 35 into the tray with the positive and negative posts in the same positions as the old battery.
• Make sure the battery sits flat and does not rock in the tray.
• Install the hold-down bracket using the 10mm socket, ratchet handle 3/8-inch drive, and socket extension 6-inch 3/8-inch drive.
• Tighten the hold-down evenly with the torque wrench inch-pound 3/8-inch drive.
• Torque to 4-6 Nm (35-53 in-lbs)

Step 8: Install Anti-Corrosion Washers

• Place one battery anti-corrosion felt washer over the positive battery post.
• Place one battery anti-corrosion felt washer over the negative battery post.
• Push each washer down until it sits flat on top of the battery case.

Step 9: Connect the Positive Cable First

• Install the positive cable clamp onto the positive battery post.
• Push the clamp fully down on the post.
• Use the 10mm socket and torque wrench inch-pound 3/8-inch drive to tighten the terminal clamp nut.
• Torque to 4-6 Nm (35-53 in-lbs)
• Close the red plastic terminal cover.

Step 10: Connect the Negative Cable Last

• Install the negative cable clamp onto the negative battery post.
• Push the clamp fully down on the post.
• Use the 10mm socket and torque wrench inch-pound 3/8-inch drive to tighten the terminal clamp nut.
• Torque to 4-6 Nm (35-53 in-lbs)
• Spray a light coat of battery terminal protector spray on both terminals.

Step 11: Remove the Memory Saver

• If used, unplug the memory saver 12V OBD-II from the OBD-II port.
• Make sure no tools are left in the engine bay.
• Close the hood securely.

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✅ After Repair

• Start your CX-5 and let it idle for 2-3 minutes.
• Check that the battery warning light turns off after startup.
• If the power windows lost auto-up/auto-down function, initialize each affected window: turn ignition ON, fully lower the window, then fully raise it and hold the switch up for about 2 seconds.
• Reset the clock and infotainment preferences if needed.
• Drive normally for 10-15 minutes so the vehicle can relearn idle and charging behavior.
• Recycle the old battery properly. Most parts stores accept it as a core return.

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💰 DIY vs Shop Cost

Shop Cost: $250-$430 (parts + labor)

DIY Cost: $170-$290 (parts only)

You Save: $80-$140 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.