why does my battery light come on in my Toyota Corolla E140 (2006-2013)?

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, wrench set, and safety goggles.
• Ensure the vehicle is parked on a flat, stable surface and the engine is off.

2. Battery Inspection

• Disconnect the negative terminal (black) first, followed by the positive terminal (red).
• Clean the battery terminals using a wire brush if corrosion is present.
• Inspect the battery case for cracks or leaks; replace if damaged.

3. Alternator Testing

• Locate the alternator and check the wiring harness for loose or damaged connections.
• Measure the alternator output using a multimeter by connecting the leads to the battery terminals while the engine is running.
  • If the voltage is below 13.7 volts, replace the alternator.
• Remove the alternator belt by loosening the tensioner and sliding the belt off the pulley.

4. Alternator Replacement (if necessary)

• Unbolt the alternator from its mount using the socket set.
• Disconnect the electrical connections from the alternator.
• Install the new alternator by reversing the removal process and securing it with bolts.
• Reinstall the alternator belt and adjust tension as required.

5. Reconnect Battery

• Connect the positive terminal (red) first, followed by the negative terminal (black).
• Ensure all connections are tight and secure.