Downhill assist control operation switch (test mode dtc)

The downhill assist control switch is connected to the skid control ecu in the abs and traction actuator.

Dtc c1379/74 can be detected when the downhill assist control switch sends the downhill assist control switch signal or test mode ends. Dtc c1379/74 is output only in test mode.

Refer to downhill assist control switch circuit (see page bc-157).

When replacing the abs and traction actuator, perform zero point calibration (see page bc-24).

1. Check wire harness (skid control ecu - body ground)

1. 1
   Disconnect the a19 ecu.
2. 2
   Measure the resistance of the wire harness side connector.

Standard resistance

2. Inspect downhill assist control switch

1. 1
   Remove the downhill assist control switch.
2. 2
   Measure the resistance of the switch.

Standard resistance

3. Check wire harness (skid control ecu - downhill assist control switch)

1. 1
   Disconnect the a19 ecu connector.
2. 2
   Disconnect the e31 switch connector.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance

The skid control ecu inputs the stop light switch signal and detects the status of the brake operation.

When replacing the abs and traction actuator, perform zero point calibration (see page bc-24).

1. 1
   Check stop light (operation)
2. 2
   Check that the light illuminates when the brake pedal is depressed, and turns off when the brake pedal is released.

Ok

2. Check wire harness (skid control ecu - battery)

1. 1
   Disconnect the a19 ecu connector.
2. 2
   Measure the voltage of the wire harness side connector.

Standard voltage

1. 1
   Check wire harness (skid control ecu)
2. 2
   Disconnect the a19 ecu connector.
3. 3
   Measure the resistance of the wire harness side connector

Standard resistance

1. 1
   Perform active test by intelligent tester (stop light relay)
2. 2
   Select the active test, generate a control command, and then check that the stop light relay operates.

   

1. 1
   Reconfirm dtc
2. 2
   Clear the dtc (see page bc-47).
3. 3
   Start the engine.
4. 4
   Drive the vehicle at a speed of 5 km/h or more for several seconds.
5. 5
   Check if the same dtc is output (see page bc-47).

Result

6. Inspect stop light control relay (marking: brk)

1. 1
   Remove the stop light control relay from the engine room no. 1 Relay block.
2. 2
   Measure the resistance of the relay.

Standard resistance

7. Check wire harness (engine room no. 1 Relay block - skid control ecu and battery)

1. 1
   Remove the stop light control relay.
2. 2
   Disconnect the a19 ecu connector.
3. 3
   Measure the voltage of the wire harness side connector.

Standard voltage

4. Measure the resistance of the wire harness side connector.

Standard resistance

1. 1
   Reconfirm dtc
2. 2
   Clear the dtc (see page bc-47).
3. 3
   Start the engine.
4. 4
   Drive the vehicle at a speed of 5 km/h or more for several seconds.
5. 5
   Check if the same dtc is output (see page bc-47).

Result

9. Check wire harness (stop light switch - battery)

1. 1
   Disconnect the a3 switch connector.
2. 2
   Measure the voltage of the wire harness side connector.

Standard voltage

10. Inspect stop light switch assembly

1. 1
   Remove the stop light switch connector.
2. 2
   Measure the resistance of the switch.

Standard resistance

11. Check wire harness (stop light switch - stop light control relay)

1. 1
   Disconnect the a3 switch connector.
2. 2
   Remove the stop light control relay.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance

12. Inspect stop light control relay (marking: brk)

1. 1
   Remove the stop light control relay from the engine room no. 1 Relay block.
2. 2
   Measure the resistance of the relay.

Standard resistance

13. Check wire harness (stop light and rear combination light - control relay)

1. 1
   Disconnect the q1, k12 and k14 light connectors.
2. 2
   Remove the stop light control relay.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance