why does my Toyota Highlander Third Generation (2014-2019) not start sometimes?

Solution

1. Preparation

• Tools Required: OBD-II scanner, multimeter, socket set, torque wrench
• Disconnect the negative battery terminal to prevent electrical shorts.
• Ensure the vehicle is in park or neutral.

2. Battery Inspection and Replacement

• Sub-steps:
  1. Remove the battery terminals (negative first, then positive).
  2. Inspect the battery for any physical damage or swelling.
  3. Clean the terminals and connections with a wire brush.
  4. If the battery voltage is low (below 12.4 volts) or it is more than 3-5 years old, replace the battery.
  5. Install a new battery, connecting the positive terminal first, followed by the negative terminal.
  6. Torque the terminal connections to 12-15 ft-lbs.

3. Starter Motor Testing and Replacement

• Sub-steps:
  1. Locate the starter motor (usually at the rear of the engine near the transmission).
  2. Disconnect the electrical connectors from the starter.
  3. Using a multimeter, check for battery voltage at the starter terminal when the key is turned to the start position.
  4. If no voltage is detected, the ignition switch may need replacement.
  5. If voltage is present but the starter doesn't engage, remove the starter and bench test it with direct battery voltage.
  6. If the starter fails the bench test, replace it with a new starter.
  7. Reinstall the starter and torque bolts to manufacturer specifications.