U0164 - LOST COMMUNICATION WITH HVAC CONTROL MODULE

The U0164 OBDII fault code basically means that the HVAC Control Module (Ventilation, Heating, and Air Conditioning) and other vehicle modules have been unable to communicate with each other. The circuit used for such communication is the Control Area Network or CAN bus.

The HVAC control module is normally found in the instrument panel and receives inputs from different sensors, which are often connected directly to it. With such input signals, the module can control the interior temperature of the vehicle.

• Check Engine lamp illumination.
• HVAC Control Module does not work.

The reasons for the U0164 OBD2 diagnostic code setting are:

• The CAN bus positive or negative circuit may be open.
• A Control Area Network power or signal ground circuit may be shorted.
• The HVAC Control Module may be faulty.

The steps to follow for troubleshooting the DTC U0164 OBDII code are:

• As the first step for diagnosis, it is advisable to consult the TSB (Technical Service Bulletins). It is also necessary to check if there are other fault codes stored, especially if they are related to CAN bus communication.
• Based on the vehicle's information source, check the location of the fuses that activate the HVAC Control Module and proceed to perform a thorough check, in order to verify that they are in good condition. Verify that the connections do not present inconsistencies. Performs the necessary repairs.
• Disconnect the negative battery cable and then unplug the HVAC Control Module Then proceed to check the connectors and wiring for obvious damage, such as burns or high levels of corrosion. Make corrections as required.
• Even with the HVAC Control Module connector disconnected, verify that there is power and ground signal to the module. Using a wiring diagram determine where the main power and ground points are on the connector. Make appropriate adjustments if one of these values is not present.