how to diagnose electrical problems in my Toyota Corolla E170 (2013-2019)

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, fuse puller, socket set, and basic hand tools.
• Disconnect the negative battery terminal to prevent any electrical shorts during inspection.

2. Battery Inspection

• Remove the battery terminals (negative first, then positive).
• Clean the terminals and connectors with a wire brush if corrosion is present.
• Check the battery voltage using a multimeter; replace the battery if it’s below 12.4V.

3. Fuse Inspection

• Open the fuse box and use a fuse puller to check each fuse's condition.
• Replace any blown fuses with the same amperage rating.
• Ensure the fuse box cover is securely closed after inspection.

4. Wiring and Ground Connections

• Inspect wiring harnesses for physical damage or loose connections.
• Secure or replace damaged wiring as necessary.
• Clean ground connections by disconnecting and sanding the contact points before reattaching.

5. Alternator Testing

• Reconnect the battery and start the engine.
• Use a multimeter to measure voltage at the battery terminals; it should read between 13.8V and 14.4V.
• If the voltage is lower, consider replacing the alternator.