Open in stop light switch circuit

The skid control ecu detects the brake operating conditions through a signal transmitted by the stop light switch. The skid control ecu incorporates an open circuit detection circuit. This dtc is set under either of the following conditions:

• An open is detected in the stop light signal input line when the stop light switch is off.
• An open is detected in the stop light circuit lead to the ground when the stop light switch is off.

1. 1
   Read value of intelligent tester (stop light switch)
2. 2
   Check the data list for proper functioning of the stop light switch.

   

2. Check wire harness (stp voltage)

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

Standard voltage

1. 1
   Inspect fuse (stop, ecu-ig1)
2. 2
   Remove the stop fuse and ecu-ig1 fuse from the instrument panel junction block.
3. 3
   Measure the resistance of the fuse.

Standard resistance: below 1

4. 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.

   

   

5. Inspect stop light switch assembly

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

Standard resistance

1. 1
   Check wire harness (skid control ecu - stop light switch)
2. 2
   Disconnect the a19 ecu connector.
3. 3
   Disconnect the a3 switch connector.
4. 4
   Measure the resistance of the wire harness side connectors.

   

1. 1
   Disconnect the a19 ecu connector.
2. 2
   Disconnect the a3 switch connector.
3. 3
   Measure the resistance of the wire harness side connectors.

Standard resistance

1. 1
   Reconfirm dtc
2. 2
   Clear the dtc (see page bc-47).
3. 3
   Check if the same dtc is output (see page bc-47).

Result