CAN COMMUNICATION SYSTEM(w/ Toyota Safety Sense) Open in Bus 3 Main Bus Line

DESCRIPTION

There may be an open circuit in one of the bus 3 main lines when the resistance between terminals 6 (CA3H) and 21 (CA3L) of the central gateway ECU (network gateway ECU) is 70 Ω or higher.

Symptom Trouble Area
Resistance between terminals 6 (CA3H) and 21 (CA3L) of central gateway ECU (network gateway ECU) is 70 Ω or higher.

  • CAN main bus line or connector

  • Central gateway ECU (network gateway ECU)

  • No. 1 junction connector

This malfunction is not related to the lines of a CAN main bus branch or to ECUs or sensors connected a CAN main bus branch.

WIRING DIAGRAM

B0047EOE02

CAUTION / NOTICE / HINT

Note


  • Turn the ignition switch off before measuring the resistances of the CAN main wire and the CAN branch wire.

  • After the ignition switch is turned off, check that the key reminder warning system and light reminder warning system are not in operation.

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

Tech Tips

Operating the ignition switch, any switches or any doors triggers related ECU and sensor communication with the CAN, which causes resistance variation.

PROCEDURE


  1. CHECK FOR OPEN IN CAN BUS LINES (CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))


    1. Remove the central gateway ECU (network gateway ECU) Click here.

    2. B00457CE02
      Text in Illustration
      *a

      Component without harness connected

      (Central Gateway ECU (Network Gateway ECU))

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      F136-6 (CA3H) - F136-21 (CA3L) Always 108 to 132 Ω
      F136-19 (CAYH) - F136-20 (CAYL) Always 108 to 132 Ω

    NG

    REPLACE CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU) Click here

    OK

  2. CHECK FOR OPEN IN CAN BUS LINES (NO. 1 JUNCTION CONNECTOR)


    1. Reinstall the central gateway ECU (network gateway ECU) Click here.

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

    3. B0048BSE02
      Text in Illustration
      *a

      Front view of wire harness connector

      (to No. 1 Junction Connector)
      *b to Central Gateway ECU (Network Gateway ECU) (CA3H and CA3L Terminal)
      *c to Central Gateway ECU (Network Gateway ECU) (CAYH and CAYL Terminal)

      Disconnect the No. 1 junction connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Connected to
      F136-7 (CANH) - F136-18 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU) (CA3H and CA3L terminal)
      F136-6 (CANH) - F136-17 (CANL) Cable disconnected from negative (-) battery terminal 108 to 132 Ω Central gateway ECU (network gateway ECU) (CAYH and CAYL terminal)

    OK

    REPLACE NO. 1 JUNCTION CONNECTOR

    NG

    REPAIR OR REPLACE CAN MAIN BUS LINE OR CONNECTOR (NO. 1 JUNCTION CONNECTOR - CENTRAL GATEWAY ECU (NETWORK GATEWAY ECU))