CAN COMMUNICATION SYSTEM > Air Conditioning Amplifier Communication Stop Mode

for Preparation Click here


DESCRIPTION


Detection Item
Symptom
Trouble Area
Air Conditioning Amplifier Communication Stop Mode
Either condition is met:
  1. "Air Conditioning Amplifier" is not displayed on the CAN Bus Check screen of the GTS (Click here)
  2. Communication system DTCs (DTCs that start with U) that correspond to "Air Conditioning Amplifier Communication Stop Mode" in "DTC Combination Table" are output (Click here)
  1. Air conditioning amplifier assembly branch line or connector
  2. Power source circuit of air conditioning amplifier assembly
  3. Air conditioning amplifier assembly ground circuit
  4. Air conditioning amplifier assembly

WIRING DIAGRAM


C240765E38


C240765E39


INSPECTION PROCEDURE

NOTICE:
  1. 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 or any 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.
  2. After turning the ignition switch off, waiting time may be required before disconnecting the cable from the negative (-) battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) battery terminal notices before proceeding with work (Click here).
  3. 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).
  4. After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.
  5. DTC check procedure: Turn the ignition switch to ON and wait at least 10 seconds.
  6. 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).

HINT:
  1. Operating the ignition 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.
  2. 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.
1.CHECK FOR OPEN IN CAN BUS LINES (AIR CONDITIONING AMPLIFIER ASSEMBLY BRANCH LINE)

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



    C240533E19

  1. Disconnect the I77 air conditioning amplifier assembly connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    I77-11 (CANH) - I77-12 (CANL)
    		Cable disconnected from negative (-) battery terminal
    		54 to 69 Ω
    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Air Conditioning Amplifier Assembly)


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


2.CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    C240533E20

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    I77-14 (GND) - Body ground
    		Cable disconnected from negative (-) battery terminal
    		Below 1 Ω

  1. Connect the cable to the negative (-) battery terminal.

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

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    I77-1 (IG+) - Body ground
    		Ignition switch ON
    		11 to 14 V
    I77-21 (B) - Body ground
    		Ignition switch off
    		11 to 14 V
    Text in Illustration 
    *a
    		Front view of wire harness connector
    (to Air Conditioning Amplifier Assembly)

    Result:
    Result
    		Proceed to
    OK (for TMC, TMMR Made)
    		A
    OK (for TMMK Made)
    		B
    NG
    		C


C
REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)

B
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (for TMMK Made) (Click here)
A

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (for TMC, TMMR Made) (Click here)