how to diagnose a dead battery in my Toyota Highlander Third Generation (2014-2019)?

Solution

1. Preparation

• Ensure the vehicle is in a safe location with the engine off.
• Gather necessary tools and parts.
• Tools Required: Multimeter, Battery tester, Wrench set, Wire brush (for cleaning terminals), Safety gloves and goggles.

2. Address Battery Issues

• Clean Battery Terminals:

  1. Disconnect the negative (-) terminal first, followed by the positive (+) terminal.
  2. Use a wire brush to clean any corrosion from the terminals and cable ends.
  3. Reconnect the positive terminal first, then the negative terminal.

• Replace the Battery (if necessary):

  1. Remove the battery hold-down bracket using the appropriate wrench.
  2. Carefully lift the battery out of the tray.
  3. Place the new battery in the tray, ensuring it is securely seated.
  4. Connect the positive terminal first, followed by the negative terminal.
  5. Reinstall the hold-down bracket and tighten to specifications.

3. Verify Alternator Function

• After replacing the battery, start the vehicle and measure the voltage at the battery terminals again. Ensure it reads between 13.8 to 14.4 volts while the engine is running. If not, further diagnose the alternator.