🔧 Supra - 12V Battery Replacement

Your Supra’s 12V battery lives in the rear cargo area. Replacing it is straightforward, but you must disconnect/reconnect in the correct order and (ideally) register the new battery so the charging system knows it’s new.

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

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⚠️ Safety & Precautions

• 🛑 Turn the car OFF, key/fob away from the car, and wait 5-10 minutes before touching the battery (modules go to sleep).
• 🧤 Wear gloves and safety glasses; batteries can spark if tools touch metal.
• 🔌 Disconnect the negative (-) terminal first and reconnect it last.
• 🚫 Do not let your wrench touch the body metal while on the positive (+) terminal.
• 🔋 Use the same type battery (typically AGM) to avoid charging issues.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 13mm socket
• Ratchet
• 6" socket extension
• Trim clip removal tool
• Torque wrench (5–30 Nm range)
• Work gloves
• Safety glasses
• OBD memory saver (optional)
• Scan tool with battery registration (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V AGM battery (OEM-equivalent fit for Supra) - Qty: 1
• Battery terminal protectant spray - Qty: 1
• Anti-corrosion terminal washers (optional) - Qty: 1 set

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📋 Before You Begin

• 🅿️ Park on level ground, shift to Park, and set the parking brake.
• 🔑 Keep the key/fob at least 10 feet away from the car.
• ⏳ Wait 5-10 minutes after shutting the car off before disconnecting the battery.
• 🔌 If you’re using an OBD memory saver (a device that keeps power to the car while the battery is out), connect it now per its instructions.
• 🧠 Plan for battery registration: if you install a new battery without registering, the car may not charge it correctly or may set faults.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the battery in the rear cargo area

• Open the hatch.
• Lift the cargo floor panel.
• Use a trim clip removal tool to carefully remove any clips/fasteners holding the right-side access cover (battery area), then remove the cover.

Step 2: Disconnect the negative (-) terminal

• Locate the negative (-) clamp on the battery.
• Use a 10mm socket with a ratchet to loosen the clamp nut.
• Lift the clamp off the battery post and tuck it aside so it cannot spring back onto the post.
• Tip: Wrap the cable end with a rag.
• When reinstalling later: Torque to 5 Nm (44 in-lbs).

Step 3: Disconnect the positive (+) terminal

• Open the positive (+) terminal cover (usually a red plastic cover).
• Use a 10mm socket with a ratchet to loosen the clamp nut.
• Lift the clamp straight up off the post and position it aside so it cannot touch metal.
• When reinstalling later: Torque to 5 Nm (44 in-lbs).

Step 4: Disconnect the battery vent tube (if equipped)

• Look for a small plastic hose on the side of the battery (this vents battery gases).
• Pull it straight out by hand. Do not tear or kink it.

Step 5: Remove the battery hold-down and lift the battery out

• Find the battery hold-down bracket at the base of the battery.
• Use a 13mm socket, ratchet, and 6" socket extension to remove the hold-down bolt(s).
• Lift the battery straight up and out. Batteries are heavy—use both hands.
• When reinstalling later: Torque hold-down to 24 Nm (18 ft-lbs).

Step 6: Install the new battery

• Set the new battery into the tray in the same orientation as the old one.
• Reinstall the hold-down bracket using the 13mm socket, then Torque hold-down to 24 Nm (18 ft-lbs) using a torque wrench.
• Reconnect the vent tube by pushing it fully into the battery vent port (if equipped).

Step 7: Reconnect terminals (positive first, negative last)

• Install the positive (+) clamp first. Use a 10mm socket and torque wrench: Torque to 5 Nm (44 in-lbs).
• Close the positive terminal cover.
• Install the negative (-) clamp last. Use a 10mm socket and torque wrench: Torque to 5 Nm (44 in-lbs).
• Spray a light coat of battery terminal protectant on the connections.

Step 8: Register the new battery (recommended)

• Connect a scan tool with battery registration (specialty) to the OBD port.
• Use the scan tool’s function for Battery Replacement / Battery Registration and follow the prompts.
• If the battery type/capacity changed (example: different Ah rating), select the correct option during registration.

Step 9: Reinstall trim and cargo floor

• Reinstall the battery access cover and any clips using the trim clip removal tool.
• Reinstall the cargo floor panel.

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✅ After Repair

• 🔎 Start the car and confirm there are no warning messages.
• 🧾 If you used no memory saver, reset the clock/date and check radio settings as needed.
• 🪟 If a window acts odd, fully raise it, then hold the switch up for 5 seconds (relearn).
• 🧰 Scan for codes if any lights remain on after a short drive.

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💰 DIY vs Shop Cost

Shop Cost: $350-$650 (parts + labor)

DIY Cost: $200-$450 (parts only)

You Save: $150-$200 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.