DTC U0424-81: HVAC Control Module to Hybrid Powertrain Control Module Invalid Serial Data Received [11/2023 - ]: Procedure
WARNING: This page is about a different car, the 2025 Toyota Highlander and 2024 Toyota Highlander. However, it is still accessible from the selected car via links, so may be relevant.
- CHECK DTC OUTPUT (AIR CONDITIONER)
- Check if DTCs related to the Air Conditioning System (A/C) are output.
Body Electrical > Air Conditioner > Trouble Codes
Result
Result Proceed to DTCs related to Air Conditioning System (A/C) are not output. A DTCs related to Air Conditioning System (A/C) are output. B - Turn the ignition switch off.
Result:
A
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY. Refer to REMOVAL [11/2023 - ]
Result:
B
GO TO DTC CHART (AIR CONDITIONING SYSTEM). Refer to DIAGNOSTIC TROUBLE CODE CHART [11/2023 - ]
- Check if DTCs related to the Air Conditioning System (A/C) are output.