🔧 Highlander - Starter Motor Replacement

Your Highlander Hybrid does not use a conventional starter motor like a non-hybrid Highlander. The gasoline engine is started by the hybrid system through the transaxle motor-generator, so there is no separate bolt-on starter motor to replace.

If your Highlander will not “READY,” cranks abnormally, or will not start the engine, the repair is usually related to the 12-volt battery, hybrid control system, relays, inverter system, wiring, or transaxle motor-generator, not a starter motor.

Difficulty Level: Advanced | Estimated Time: Diagnosis: 0.5-2 hours

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⚠️ Safety & Precautions

• ⚠️ Your Highlander has a high-voltage hybrid system. Orange cables and hybrid components can be dangerous.
• ⚠️ Do not disconnect, probe, or remove orange high-voltage cables unless you are hybrid-certified and using insulated high-voltage safety equipment.
• ⚠️ Always turn the vehicle OFF and keep the key fob at least 15 feet away before working under the hood.
• ⚠️ Disconnecting the 12-volt battery may erase learned settings and can trigger system resets.
• ⚠️ A weak 12-volt battery can make a hybrid Toyota act like it has a bad starter, even though it has no starter motor.

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🔧 Required Tools

You'll need the following tools for this repair:

• Digital multimeter
• 10mm wrench
• 10mm socket
• 3/8-inch ratchet
• OBD-II scan tool with Toyota hybrid data capability
• Battery charger rated for AGM 12-volt batteries
• Battery terminal cleaning brush
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12-volt AGM battery - Qty: 1, if testing fails
• Battery terminal protectant - Qty: 1
• Battery terminal cleaning pads - Qty: 1 pack

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📋 Before You Begin

• Park your Highlander on level ground.
• Shift to Park and set the parking brake.
• Turn the vehicle OFF completely.
• Keep the key fob away from the vehicle so the hybrid system does not wake up while you work.
• Open the hood and wait at least 5 minutes before touching battery terminals.
• A multimeter is a small electrical tester used to measure battery voltage.
• An OBD-II scan tool plugs into the diagnostic port and reads trouble codes from the vehicle computers.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Confirm There Is No Starter Motor

• Do not search for or remove a starter from your Highlander Hybrid. This model does not have a conventional starter motor.
• The engine is spun by the hybrid transaxle motor-generator when the system enters READY mode.
• If a parts listing shows a starter for a 2017 Highlander, it is for a non-hybrid model and does not apply to your Highlander.

Step 2: Check the 12-Volt Battery Voltage

• Use a digital multimeter set to DC volts.
• Place the red meter lead on the positive battery terminal and the black meter lead on the negative battery terminal.
• A healthy fully charged 12-volt battery should read about 12.6 volts with the vehicle OFF.
• If the reading is below 12.2 volts, charge the battery before continuing.
• If the reading is below 12.0 volts, the battery may be too weak to boot the hybrid system.
• Weak 12-volt batteries cause many no-starts.

Step 3: Inspect the Battery Terminals

• Use safety glasses and nitrile gloves.
• Use a 10mm wrench to check that the battery terminal clamps are snug.
• If corrosion is present, disconnect the negative terminal first using a 10mm wrench.
• Disconnect the positive terminal second using a 10mm wrench.
• Use a battery terminal cleaning brush to clean the battery posts and cable clamps.
• Reconnect the positive terminal first using a 10mm wrench.
• Reconnect the negative terminal second using a 10mm wrench.
• Tighten the terminal clamps securely, but do not over-tighten them.

Step 4: Charge or Replace the 12-Volt Battery if Needed

• Use a battery charger rated for AGM 12-volt batteries.
• Connect the charger positive clamp to the battery positive terminal.
• Connect the charger negative clamp to a clean chassis ground or the battery negative terminal.
• Charge the battery fully, then retest it with the digital multimeter.
• If the battery will not hold at least 12.4-12.6 volts after charging, replace the 12-volt AGM battery.

Step 5: Scan the Hybrid System for Codes

• Use an OBD-II scan tool with Toyota hybrid data capability.
• Plug the scan tool into the OBD-II port under the driver side dashboard.
• Turn the vehicle ON without pressing the brake pedal if possible, or attempt READY mode if instructed by the scan tool.
• Read codes from the hybrid control, engine control, ABS/VSC, and body control modules.
• Record all codes before clearing anything.
• If codes related to the inverter, hybrid battery, motor-generator, or immobilizer are present, diagnose those systems before replacing any parts.

Step 6: Check READY Mode Operation

• Press the brake pedal firmly.
• Press the POWER button once.
• Look for the green READY indicator on the instrument cluster.
• If READY appears, the hybrid system is active and the engine may start only when needed.
• If READY does not appear, continue diagnosis with the scan tool instead of looking for a starter motor.

Step 7: Know When to Stop

• If the 12-volt battery tests good and your Highlander still will not enter READY mode, do not attempt high-voltage repairs at home.
• Hybrid transaxle, inverter, and high-voltage battery diagnosis requires Toyota hybrid procedures and insulated safety equipment.
• At that point, the safest next step is professional hybrid diagnosis.

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✅ After Repair

• Confirm the vehicle enters READY mode normally.
• Check that the dashboard warning lights turn off after startup.
• Use the OBD-II scan tool to clear low-voltage-related codes only after recording them.
• Test drive your Highlander at low speed first and confirm normal hybrid operation.
• Reset clock, radio presets, and window auto-up functions if they were lost after battery disconnection.

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💰 DIY vs Shop Cost

Shop Cost: $150-$450 for no-start diagnosis, more if hybrid component repair is needed

DIY Cost: $0-$280 for basic battery testing, charging, terminal service, or 12-volt battery replacement

You Save: $100-$250 by checking the 12-volt system yourself first!

Shop labor rates vary but typically run $100-$150/hour. This diagnosis takes a shop approximately 0.5-2 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.