how to address the error code U0101 in my Toyota Corolla E170 (2013-2019)?

Solution

1. Preparation

• Gather required tools and parts.
• Disconnect the negative battery terminal to ensure safety.
• Clear existing error codes using an OBD-II scanner.

2. Inspect Wiring and Connectors

• Remove any protective covers to access the wiring harness between the ECM and TCM.
• Visually inspect wiring for frays, breaks, or corrosion.
• Disconnect the connectors at both the ECM and TCM ends.
• Clean any corrosion or debris from the connectors using electrical contact cleaner.

3. Repair or Replace Damaged Components

• If any damaged wires are found, splice in new wire sections and solder them securely.
• If connectors are damaged, replace them with OEM connectors.
• Reconnect the wiring harness securely to both the ECM and TCM.

4. Test and Verify Communication

• Reconnect the negative battery terminal.
• Use the OBD-II scanner to check for error codes again.
• Start the vehicle and verify that the check engine light does not illuminate.
• Test drive the vehicle to ensure proper transmission function and shifting.