🔧 Impreza - 12V Battery Replacement

Replacing the 12V battery restores reliable starting and stable electrical power for your Impreza’s computers and accessories. The job is simple, but the order you disconnect and reconnect the cables matters to prevent damage or sparks.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Turn ignition OFF and keep the key fob at least 10 ft away.
• ⚠️ Never let a tool touch both battery terminals at once.
• ⚠️ Disconnect the negative (–) terminal first and reconnect it last.
• ⚠️ Batteries can vent explosive gas—no smoking or sparks nearby.
• ⚠️ Wear gloves and safety glasses; battery acid is corrosive.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm wrench
• 10mm socket
• Ratchet
• 3-inch extension
• Battery terminal brush
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V battery (Group 35, top-post) - Qty: 1
• Battery terminal anti-corrosion spray - Qty: 1
• Dielectric grease - Qty: 1
• Battery terminal felt washers - Qty: 2

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and make sure all lights and accessories are OFF.
• If you want to preserve radio presets/clock, write them down first.
• Know this term: a battery terminal clamp is the metal connector on the cable that grips the battery post.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the battery

• Open the hood and locate the 12V battery in the engine bay.
• If there is a plastic battery cover, remove it by hand.

Step 2: Disconnect the negative (–) terminal

• Use a 10mm wrench to loosen the nut on the negative (–) terminal clamp.
• Twist the clamp gently and lift it off the post, then push it aside so it cannot spring back.
• Negative off first prevents accidental shorting.
• Torque to 5.4 Nm (4.0 ft-lbs) when reinstalling.

Step 3: Disconnect the positive (+) terminal

• Flip open the red terminal cover (if equipped).
• Use a 10mm wrench to loosen the nut on the positive (+) terminal clamp and remove the clamp from the post.
• Torque to 5.4 Nm (4.0 ft-lbs) when reinstalling.

Step 4: Remove the battery hold-down

• Use a 10mm socket, ratchet, and 3-inch extension to remove the hold-down nuts.
• Lift off the hold-down bracket and set it aside.
• Torque to 7.5 Nm (5.5 ft-lbs) when reinstalling.

Step 5: Remove the old battery

• Wearing nitrile gloves and safety glasses, lift the battery straight up and out.
• Keep it upright to avoid any acid leakage.

Step 6: Clean the terminals and tray

• Use a battery terminal brush to clean the inside of both cable clamps until shiny.
• Wipe the battery tray area clean by hand (remove debris and corrosion).

Step 7: Install the new battery

• Place the new battery into the tray in the same orientation as the old one (posts in the same positions).
• Reinstall the hold-down bracket using the 10mm socket, ratchet, and 3-inch extension.
• Torque to 7.5 Nm (5.5 ft-lbs).

Step 8: Reconnect the positive (+) terminal first

• Install felt washer (if using), then place the positive clamp fully down on the post.
• Use a 10mm wrench to tighten the clamp.
• Apply a thin dab of dielectric grease on the outside of the connection, then apply battery terminal anti-corrosion spray.
• Torque to 5.4 Nm (4.0 ft-lbs).

Step 9: Reconnect the negative (–) terminal last

• Install felt washer (if using), then place the negative clamp fully down on the post.
• Use a 10mm wrench to tighten the clamp.
• Apply battery terminal anti-corrosion spray after tightening.
• Torque to 5.4 Nm (4.0 ft-lbs).

Step 10: Final check

• Gently wiggle each clamp by hand—there should be no movement.
• Reinstall any battery cover by hand.

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✅ After Repair

• Start the engine and confirm the dash lights behave normally.
• Set the clock and re-save radio presets if they reset.
• Power window reset (if needed): with engine running, fully raise the driver window and keep holding the switch UP for 2 seconds.
• If any warning lights stay on after a short drive, scan for codes (a parts store scan is fine for a quick check).

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💰 DIY vs Shop Cost

Shop Cost: $220-$380 (parts + labor)

DIY Cost: $140-$260 (parts only)

You Save: $80-$120 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?

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