CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0164
| DTC Code | DTC Name |
|---|---|
| U0164 | Lost Communication with HVAC Control Module |
DESCRIPTION
| DTC Code | DTC Detection Condition | Trouble Area |
|---|---|---|
| U0164 | There is no communication from the air conditioning amplifier assembly. |
|
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For vehicles with a 1WW engine type, entry and start system and automatic air conditioning system.
WIRING DIAGRAM
| *a | No. 5 CAN Junction Connector |
| *b | from Battery |
| *c | from IG1 Relay |
| *d | Air Conditioning Amplifier Assembly |
CAUTION / NOTICE / HINT
Note
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Because the order of diagnosis is important to allow correct diagnosis, make sure to begin troubleshooting using How to Proceed with Troubleshooting when CAN communication system related DTCs are output Click here.
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Before measuring the resistance of the CAN bus, turn the ignition switch off and leave the vehicle for 1 minute or more without operating the key, switches or opening or closing the doors. After that, disconnect the cable from the negative (-) battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.
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After turning the ignition switch off, waiting time may be required before disconnecting the cable from the battery terminal. Therefore, make sure to read the disconnecting the cable from the battery terminal notice before proceeding with work Click here.
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Inspect the fuses for circuits related to this system before performing the following inspection procedure.
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After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
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After the repair, perform CAN Bus Check and check that all the ECUs and sensors connected to the CAN communication system are displayed Click here.
Tech Tips
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Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.
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Even after DTCs are cleared, if a DTC is stored again after driving the vehicle for a while, the malfunction may be occurring due to vibration of the vehicle. In such a case, wiggling the ECUs or wire harness while performing the inspection below may help determine the cause of the malfunction.
PROCEDURE
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CHECK FOR OPEN IN CAN BUS WIRE (AIR CONDITIONING AMPLIFIER ASSEMBLY CAN BRANCH WIRE)
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Text in Illustration *a Front view of wire harness connector
(to Air Conditioning Amplifier Assembly)
Disconnect the cable from the negative (-) battery terminal.
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Disconnect the air conditioning amplifier assembly connector.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance Tester Connection Condition Specified Condition H46-11 (CANH) - H46-12 (CANL) Cable disconnected from negative (-) battery terminal 54 to 69 Ω
NG 
REPAIR OR REPLACE CAN BRANCH WIRE CONNECTED TO AIR CONDITIONING AMPLIFIER ASSEMBLY (CANH, CANL)
OK 
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CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - BATTERY AND BODY GROUND)
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Text in Illustration *a Front view of wire harness connector
(to Air Conditioning Amplifier Assembly)
Connect the cable to the negative (-) battery terminal.
Note
When disconnecting the cable, some systems need to be initialized after the cable is reconnected Click here.
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Measure the resistance according to the value(s) in the table below.
Standard Resistance Tester Connection Condition Specified Condition H46-14 (GND) - Body ground Always Below 1 Ω -
Measure the voltage according to the value(s) in the table below.
Standard Voltage Tester Connection Condition Specified Condition H46-21 (B) - Body ground Always 11 to 14 V H46-1 (IG+) - Body ground Ignition switch ON 11 to 14 V
OK
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here
NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
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