🔧 RX350 - 12V Battery Replacement

This job replaces the 12V battery that powers starting and all electronics. The key points are removing the cables in the correct order (negative first) and securing the new battery so it can’t move.

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

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⚠️ Safety & Precautions

• ⚠️ Turn the vehicle fully OFF and keep the key fob 10+ feet away.
• ⚠️ Wear gloves and safety glasses; battery acid is corrosive.
• ⚠️ Remove the negative (-) cable first and install it last to prevent accidental short circuits.
• ⚠️ Do not let a tool touch the battery positive (+) and any metal body part at the same time.
• ⚠️ Batteries are heavy; lift with both hands and keep it upright.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 12mm socket
• 3/8" ratchet
• 6" socket extension
• Torque wrench (in-lb and ft-lb)
• Battery terminal puller (specialty)
• Battery terminal cleaning brush
• Shop towels
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V battery (match OEM size and terminal layout) - Qty: 1
• Battery terminal anti-corrosion spray or dielectric grease - Qty: 1
• Battery terminal felt washer set - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to P, and set the parking brake.
• Open the hood and keep it securely supported.
• Make note of radio presets and clock settings (they may reset).
• A “terminal puller” gently frees stuck clamps.

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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 compartment.
• If a plastic cover is present, remove it by hand (or use a 10mm socket if it’s bolted).

Step 2: Disconnect the negative (-) cable

• Use a 10mm socket to loosen the nut on the negative (-) terminal clamp.
• Twist the clamp gently and lift it off the battery post.
• Tuck the cable to the side so it cannot spring back and touch the terminal.
• Negative off first prevents accidental sparks.

Step 3: Disconnect the positive (+) cable

• Use a 10mm socket to loosen the nut on the positive (+) terminal clamp.
• Lift the clamp off and position it so it cannot touch the battery post.
• If there’s a protective red cover, flip it down over the positive clamp for safety.

Step 4: Remove the battery hold-down

• Remove the hold-down bracket/rod using a 12mm socket, ratchet, and 6" extension.
• Set the bracket and hardware aside where they won’t fall into the engine bay.
• Torque spec (typical Lexus/Toyota): Torque to 18 Nm (13 ft-lbs) when reinstalling.

Step 5: Remove the old battery

• Lift the battery straight up and out using both hands.
• Keep it upright to avoid any acid leakage.
• Check the battery tray for corrosion or wet spots and wipe with shop towels.

Step 6: Clean the terminals and tray

• Use a battery terminal cleaning brush to clean the inside of both cable clamps until shiny.
• If the clamps are stuck on the old battery posts, use a battery terminal puller (specialty) (a small tool that pulls the clamp off without prying).

Step 7: Install the new battery

• Place the new battery into the tray in the same orientation as the old one (positive and negative must match the cables).
• Reinstall the hold-down bracket using a 12mm socket and ratchet.
• Torque to 18 Nm (13 ft-lbs).

Step 8: Reconnect the positive (+) terminal first

• Install felt washers (if included) on the battery posts.
• Push the positive (+) clamp fully down onto the post.
• Tighten the clamp nut with a 10mm socket.
• Torque spec (typical Lexus/Toyota): Torque to 5.4 Nm (48 in-lbs).
• Apply a light coat of terminal anti-corrosion spray/dielectric grease.

Step 9: Reconnect the negative (-) terminal last

• Push the negative (-) clamp fully down onto the post.
• Tighten the clamp nut with a 10mm socket.
• Torque to 5.4 Nm (48 in-lbs).

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✅ After Repair

• Start the engine and confirm the starter cranks strongly.
• Check that the battery is secure (it should not move by hand).
• Reset the clock and radio presets if needed.
• Initialize power windows if auto-up/down doesn’t work: use the window switch to fully lower, then fully raise, holding the switch 2-3 seconds at the top.
• If warning lights appear (common after battery disconnect), drive a short loop; many will clear after a few minutes of normal driving.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $160-$280 (parts only)

You Save: $90-$170 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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