Description

Brake switch (No.1 signal) circuit malfunction

Detection condition

• The start stop unit detected the following condition 5 times continuously with the ignition switched ON (engine off or on).

• The brake switch (No.1 signal) is OFF for a continuous 3 s or more even though the brake switch (No.2 signal) changes.

Fail-safe

• Determined by brake switch (No.2 signal) with the brake pedal depressed.

Possible cause

• Brake switch connector or terminal malfunction

• Brake switch (No.1 signal) malfunction

• Brake switch (No.1 signal) power supply circuit malfunction

• Short to ground in wiring harness between MAIN 200 A fuse and brake switch terminal A

• STOP 10 A fuse malfunction

• MAIN 200 A fuse malfunction

• Open circuit in wiring harness between battery positive terminal and brake switch terminal A

• Start stop unit connector or terminal malfunction

• Short to ground in wiring harness between brake switch terminal D and start stop unit terminal 1C

• Open circuit in wiring harness between brake switch terminal D and start stop unit terminal 1C

• Start stop unit malfunction

Step

Inspection

Action

1

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Disconnect the brake switch connector.

• Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 7.

2

• Inspect the brake switch (No.1 signal).

  (See BRAKE SWITCH INSPECTION.)

• Is the brake switch (No.1 signal) normal?

Yes

Go to the next step.

No

Replace the brake switch, then go to Step 7.

(See BRAKE PEDAL REMOVAL/INSTALLATION.)

3

• Verify that the brake switch connector is disconnected.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Measure the voltage at the brake switch terminal A (wiring harness-side).

• Is the voltage B+?

Yes

Go to the next step.

No

Inspect the STOP 10 A fuse and MAIN 200 A fuse.

• Any fuse is blown:

• Refer to the wiring diagram and verify whether or not there is a common connector between MAIN 200 A fuse and brake switch terminal A.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

• Replace the fuse.

• Any fuse is damaged:

• Replace the fuse.

• All fuses are normal:

• Refer to the wiring diagram and verify whether or not there is a common connector between battery positive terminal and brake switch terminal A.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to Step 7.

4

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Disconnect the start stop unit connector.

• Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.

• Is the connector normal?

Yes

Go to the next step.

No

Repair or replace the connector, then go to Step 7.

5

• Verify that the brake switch and start stop unit connectors are disconnected.

• Inspect for continuity between brake switch terminal D (wiring harness-side) and body ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between brake switch terminal D and start stop unit terminal 1C.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has a short to ground.

Go to Step 7.

No

Go to the next step.

6

• Verify that the brake switch and start stop unit connectors are disconnected.

• Inspect for continuity between brake switch terminal D (wiring harness-side) and start stop unit terminal 1C (wiring harness-side).

• Is there continuity?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between brake switch terminal D and start stop unit terminal 1C.

If there is a common connector:

• Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.

• Repair or replace the malfunctioning part.

If there is no common connector:

• Repair or replace the wiring harness which has an open circuit.

Go to the next step.

7

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the start stop unit using the M-MDS.

  (See CLEARING DTC [START STOP UNIT].)

• Perform the work of depressing the brake pedal for 3 s or more and then releasing it for 5 times or more with the ignition switched ON (engine off or on).

• Retrieve the start stop unit DTCs using the M-MDS.

  (See DTC INSPECTION [START STOP UNIT].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the start stop unit.

  (See START STOP UNIT REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

8

• Are any other DTCs displayed?

Yes

Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [START STOP UNIT].)

No

DTC troubleshooting completed.