DTC C0040:24 [START STOP UNIT]

id0902p6021200

Description

Brake switch (No.1 signal) circuit malfunction
Detection condition
•  Start stop unit detects that the brake switch No.1 signal is in the on condition for 3 s or more continuously for a continuous 5 times even though brake switch No.2 signal changes with the ignition switched ON (engine off or on).
Fail-safe
•  Determined by brake switch (No.2 signal) with the brake pedal depressed.
Possible cause
Caution
•  Inspect the brake switch with it installed to the brake pedal, otherwise the brake switch may not operate normally. If the brake switch is removed from the brake pedal, replace the brake switch with a new one.
•  Brake switch connector or terminal malfunction
•  Brake switch (No.1 signal) malfunction
•  Start stop unit connector or terminal malfunction
•  Short to power supply in wiring harness between brake switch terminal D and start stop unit terminal 1C
•  Start stop unit malfunction

Diagnostic Procedure

Step

Inspection

Action
1
INSPECT BRAKE SWITCH CONNECTOR
•  Switch the ignition off.
•  Disconnect the negative battery terminal.
•  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 5.
2
INSPECT BRAKE SWITCH (NO.1 SIGNAL)
•  Inspect the brake switch (No.1 signal).
•  Is the brake switch (No.1 signal) normal?
Yes
Go to the next step.
No
Replace the brake switch, then go to Step 5.
(See BRAKE PEDAL REMOVAL/INSTALLATION [L.H.D.].)
(See BRAKE PEDAL REMOVAL/INSTALLATION [R.H.D.].)
3
INSPECT START STOP UNIT CONNECTOR
•  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 5.
4
INSPECT FOR SHORT TO POWER SUPPLY IN BRAKE SWITCH (NO.1 SIGNAL) CIRCUIT
•  Verify that the brake switch and start stop unit connectors are disconnected.
•  Reconnect the negative battery terminal.
•  Switch the ignition ON (engine off or on).
•  Measure the voltages at brake switch terminal D (wiring harness-side).
•  Is the voltage 0 V?
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 a short to power supply.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to power supply.
Go to the next step.
5
VERIFY THAT REPAIRS HAVE BEEN COMPLETED
•  Always reconnect all disconnected connectors.
•  Reconnect the negative battery terminal.
•  Clear the DTC for the start stop unit using the M-MDS.
•  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.
•  Is the same Pending DTC present?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the start stop unit.
Go to the next step.
No
Go to the next step.
6
VERIFY IF OTHER DTCs DISPLAYED
•  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.