CAN COMMUNICATION SYSTEM(for RHD) FC Control ECU Communication Stop Mode

DESCRIPTION

Detection Item Symptom Trouble Area
FC Control ECU Communication Stop Mode

Either condition is met:


  • "FC" is not displayed on the CAN Bus Check screen of the GTS

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  • Communication system DTCs (DTCs that start with U) that correspond to "FC Control ECU Communication Stop Mode" in "DTC Combination Table" are output

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  • FC control ECU branch line or connector

  • Power source circuit of FC control ECU

  • FC control ECU ground circuit

  • FC control ECU

WIRING DIAGRAM

A01MHIQE02

CAUTION / NOTICE / HINT

Note


  • Before measuring the resistance of the CAN bus, turn the power 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 (-) auxiliary battery terminal and leave the vehicle for 1 minute or more before measuring the resistance.

  • After turning the power switch off, waiting time may be required before disconnecting the cable from the negative (-) auxiliary battery terminal. Therefore, make sure to read the disconnecting the cable from the negative (-) auxiliary battery terminal notices before proceeding with work.

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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.

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  • After performing repairs, perform the DTC check procedure and confirm that the DTCs are not output again.

  • DTC check procedure: Turn the power switch on (IG) and wait at least 2 minutes.

  • After the repair, perform the CAN bus check and check that all the ECUs and sensors connected to the CAN communication system are displayed.

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  • Inspect the fuses for circuits related to this system before performing the following procedure.

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. CHECK FOR OPEN IN CAN BUS LINES (FC CONTROL ECU BRANCH LINE)


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

    2. A01MG26C02
      *a

      Front view of wire harness connector

      (to FC Control ECU)

      Disconnect the FC control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A48-8 (CA1H) - A48-9 (CA1L) Cable disconnected from negative (-) auxiliary battery terminal 54 to 69 Ω
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE CAN BRANCH LINE OR CONNECTOR (FC CONTROL ECU)

    OK

  2. CHECK HARNESS AND CONNECTOR (FC CONTROL ECU POWER SOURCE CIRCUIT)


    1. Disconnect the FC control ECU connector.

    2. A01MFIKC02
      *a

      Front view of wire harness connector

      (to FC Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A48-3 (E1) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω
      A47-85 (E2) - Body ground Cable disconnected from negative (-) auxiliary battery terminal Below 1 Ω

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

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      A48-43 (IG2) - Body ground Power switch ON (IG) 11 to 14 V
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FC CONTROL ECU POWER SOURCE CIRCUIT)

    OK

  3. INSPECT FC-IGCT RELAY


    1. Remove the FC-IGCT relay.

    2. Inspect the FC-IGCT relay.

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      Result
      Result
      OK
      NG

    NG

    REPLACE FC-IGCT RELAY

    OK

  4. CHECK HARNESS AND CONNECTOR (FC-IGCT RELAY POWER SOURCE CIRCUIT)


    1. A01MJ3PC02
      *1 No. 1 Motor Compartment Relay Block
      *2 FC-IGCT Relay Holder

      Remove the FC-IGCT relay.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      FC-IGCT-2 - Body ground Always Below 1 Ω

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

      Standard Voltage
      Tester Connection Switch Condition Specified Condition
      FC-IGCT-5 - Body ground Power switch off 11 to 14 V
      Result
      Result
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (FC-IGCT RELAY POWER SOURCE CIRCUIT)

    OK

  5. CHECK HARNESS AND CONNECTOR (FC-IGCT RELAY - FC CONTROL ECU)


    1. Remove the FC-IGCT relay.

    2. Disconnect the A48 FC control ECU connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      FC-IGCT-3 - A48-1 (+B1) Always Below 1 Ω
      FC-IGCT-3 - A48-20 (+B2) Always Below 1 Ω
      FC-IGCT-1 - A48-30 (RLFC) Always Below 1 Ω
      FC-IGCT-3 or A48-1 (+B1) - Body ground Always 10 kΩ or higher
      FC-IGCT-3 or A48-20 (+B2) - Body ground Always 10 kΩ or higher
      FC-IGCT-1 or A48-30 (RLFC) - Body ground Always 10 kΩ or higher
      Result
      Result
      OK
      NG

    OK

    REPLACE FC CONTROL ECU Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR