CAN COMMUNICATION SYSTEM, Diagnostic DTC:U0164

DTC Code DTC Name
U0164 Lost Communication with A/C ECU

DESCRIPTION

DTC No. DTC Detection Condition Trouble Area
U0164 No communication from the air conditioning amplifier assembly continues.

  • Air conditioning amplifier assembly branch line or connector

  • Power source circuit of air conditioning amplifier assembly

  • Air conditioning amplifier assembly

Tech Tips

This diagnosis procedure is for when DTC U0164 is output by the power management control ECU (GTS display: PM2 Gateway).

WIRING DIAGRAM

B001NAFE08

CAUTION / NOTICE / HINT

Note


  • Turn the power switch off before measuring the resistances between CAN main bus lines and between CAN branch lines.

  • Turn the power switch off before inspecting CAN main bus lines for a ground short.

  • After the power switch is turned off, check that the key reminder warning system and light reminder warning system are not operating.

  • Before measuring the resistance, leave the vehicle as is for at least 1 minute and do not operate the power switch, any other switches or the doors. If any doors need to be opened in order to check connectors, open the doors and leave them open.

Tech Tips


  • Operating the power switch, any other switches or a door triggers related ECU and sensor communication on the CAN. This communication will cause the resistance value to change.

  • 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


  1. RECONFIRM DTC OUTPUT


    1. Reconfirm DTCs.

      Tech Tips

      If DTC U1002 is output from PM2 Gateway of the power management control ECU, this indicates a sub bus 12 malfunction. Troubleshoot for DTC U1002 and check for malfunctions in the sub bus 12.

      Result
      Result Proceed to
      U1002 is not output from power management control ECU (GTS display/PM2 Gateway) A
      U1002 is output from power management control ECU (GTS display/PM2 Gateway) B

    B

    GO TO DIAGNOSIS PROCEDURE INDICATED BY OUTPUT DTC Click here

    A

  2. CHECK FOR OPEN IN CAN BUS LINES (AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH LINE)


    1. Disconnect the cable from the negative (-) auxiliary battery terminal.

    2. B001KPYE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

      Disconnect the H85 air conditioning amplifier assembly connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H85-11 (CANH) - H85-12 (CANL) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY)

    OK

  3. CHECK HARNESS AND CONNECTOR (POWER SOURCE TERMINAL)


    1. Reconnect the cable to the negative (-) auxiliary battery terminal.

    2. B001LFSE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

      Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      H85-1 (IG+) - Body ground Power switch on (IG) 11 to 14 V
      H85-21 (B) - Body ground Power switch off 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

    OK

  4. CHECK HARNESS AND CONNECTOR (GROUND TERMINAL)


    1. B001KAJE01
      Text in Illustration
      *a

      Front view of wire harness connector

      (to Air Conditioning Amplifier Assembly)

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H85-14 (GND) - Body ground Always Below 1 Ω

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GROUND CIRCUIT)