Toyota Corolla (E120): Check open circuit

  1. For the open circuit in the wire harness in fig. 1, Perform a resistance check in step (b) or a voltage check in step (c) to locate the section.

  1. Check the resistance.
  1.  Disconnect connectors a and c and measure the resistance between them.

    Resistance: 1 Ω or less

Hint

: measure the resistance while lightly shaking the wire harness vertically and horizontally. In the case of fig. 2: Between terminal 1 of connector a and terminal 1 of connector c " 10 kΩ

or higher between terminal 2 of connector a and terminal 2 of connector c " below 1 Ω

therefore, the cause is an open circuit between terminal 1 of connector a and terminal 1 of connector c.

  1. Disconnect connector b and measure the resistance between the connectors.

    In the case of fig. 3: Between terminal 1 of connector a and terminal 1 of connector b1 " below 1 w between terminal 1 of connector b2 and terminal 1 of connector c " 10 kw therefore, the cause is an open circuit between terminal 1 of connector b2 and terminal 1 of connector c.

  1. Check the voltage.
  1.  In a circuit in which voltage is applied (to the ecu connector terminal), an open circuit can be checked by conducting a voltage check.

    As shown in fig. 4, With each connector still connected, measure the voltage between the body ground and terminal 1 of connector a at the ecu 5 v output terminal, terminal 1 of connector b, and terminal 1 of connector c, in that order.

  2.  If the results are: 5 v: between terminal 1 of connector a and body ground 5 v: between terminal 1 of connector b and body ground 0 v: between terminal 1 of connector c and body ground therefore, the cause is an open circuit in the wire harness between terminal 1 of connector b and terminal 1 of connector c.

Check short circuit

    Share this page:

    Other materials:

    Under hood
    General maintenance 1. General notes maintenance requirements vary depending on the country. Check the maintenance schedule in the owner’s manual supplement. Following the maintenance schedule is mandatory. Determine the appropriate time to service the vehicle using either miles driv ...

    If your vehicle overheats
    The following may indicate that your vehicle is overheating. ● Vehicles without a multi-information display: The high engine coolant temperature warning light  comes on or a loss of power is experienced. Vehicles with a multi-information display: The engine coolant temperature gauge&n ...

    Circuit description
    When the brake pedal is depressed, the stop lamp switch assy sends a signal to the cruise control ecu assy. When the cruise control ecu assy receives this signal, it cancels the cruise control. A fail–safe function is provided so that cancel functions normally, even if there is a malfu ...