Diagnosis Procedure

WARNING: This page is about a different car, the 2016 Infiniti Q50. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

DTC "C1176" may be detected when the brake pedal and the accelerator pedal are simultaneously depressed for 1 minute or more while driving the vehicle. This is not a malfunction.

INTERVIEW FROM THE CUSTOMER

Check if the brake pedal and the accelerator pedal are simultaneously depressed for 1 minute or more while driving the vehicle.

Is there such a history?

YES

GO TO STEP 2 .

NO

GO TO STEP 3 .

PERFORM SELF-DIAGNOSIS (1)

With CONSULT
1. Erase self-diagnosis result for "ABS".
2. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
3. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
4. Depress the brake pedal several times.
5. Turn the ignition switch OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF.
6. Set the vehicle to READY/Start the engine.
  NOTE:
  Wait at least 10 seconds after set the vehicle to READY/start the engine.
7. Repeat step 5 to 6 two or more times.
8. Perform self-diagnosis for "ABS".
Is DTC "C1176" detected?

YES

GO TO STEP 3 .

NO

INSPECTION END

CHECK DATA MONITOR (1)

With CONSULT
1. Erase self-diagnosis result for "ABS".
2. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
3. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
4. Select "ABS", "DATA MONITOR" and "STOP LAMP SW2" according to this order. Check that data monitor displays "On" or "Off" when brake pedal is depressed or released. Refer to REFERENCE VALUE .
5. Select "ABS", "DATA MONITOR" and "PRESS SENSOR" according to this order. Depress the brake pedal and check if "PRESSURE SENSOR" indicates "5 bar" or less when "STOP LAMP SW2" of "DATA MONITOR" turns from "On" to "Off". Refer to REFERENCE VALUE .
Is the inspection result normal?

YES

INSPECTION END

NO

GO TO STEP 4 .

CHECK CONNECTOR
1. Turn the ignition switch OFF.
2. Check the ABS actuator and electric unit (control unit) harness connector for disconnection or looseness.
3. Check the brake pedal position switch harness connector for disconnection or looseness.
4. Check the stop lamp OFF relay 1 harness connector for disconnection or looseness.
5. Check the stop lamp OFF relay 2 harness connector for disconnection or looseness.
Is the inspection result normal?

YES

GO TO STEP 5 .

NO

Repair / replace harness or connector, securely lock the connector, and GO TO STEP 5 .

CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) POWER SUPPLY AND GROUND CIRCUIT

Check the ABS actuator and electric unit (control unit) power supply and ground circuit. Refer to DIAGNOSIS PROCEDURE .

Is the inspection result normal?

YES

GO TO STEP 6 .

NO

Repair / replace harness, connector, fuse, or fusible link.

CHECK BRAKE PEDAL POSITION SWITCH CLEARANCE
1. Turn the ignition switch OFF.
2. Check the brake pedal position switch clearance. Refer to INSPECTION AND ADJUSTMENT .
Is the inspection result normal?

YES

GO TO STEP 8 .

NO

Adjust brake pedal position switch clearance. Refer to INSPECTION AND ADJUSTMENT . GO TO STEP 7 .

CHECK DATA MONITOR (2)

With CONSULT
1. Erase self-diagnosis result for "ABS".
2. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
3. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
4. Select "ABS", "DATA MONITOR" and "STOP LAMP SW2" according to this order. Check that data monitor displays "On" or "Off" when brake pedal is depressed or released. Refer to REFERENCE VALUE .
5. Select "ABS", "DATA MONITOR" and "PRESS SENSOR" according to this order. Depress the brake pedal and check if "PRESSURE SENSOR" indicates "5 bar" or less when "STOP LAMP SW2" of "DATA MONITOR" turns from "On" to "Off". Refer to REFERENCE VALUE .
Is the inspection result normal?

YES

INSPECTION END

NO

GO TO STEP 8 .

CHECK BRAKE PEDAL POSITION SWITCH

Check the brake pedal position switch. Refer to COMPONENT INSPECTION .

Is the inspection result normal?

YES

GO TO STEP 10 .

NO

Replace the brake pedal position switch. Refer to REMOVAL AND INSTALLATION . GO TO STEP 9 .

CHECK DATA MONITOR (3)

With CONSULT
1. Erase self-diagnosis result for "ABS".
2. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
3. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
4. Select "ABS", "DATA MONITOR" and "STOP LAMP SW2" according to this order. Check that data monitor displays "On" or "Off" when brake pedal is depressed or released. Refer to REFERENCE VALUE .
5. Select "ABS", "DATA MONITOR" and "PRESS SENSOR" according to this order. Depress the brake pedal and check if "PRESSURE SENSOR" indicates "5 bar" or less when "STOP LAMP SW2" of "DATA MONITOR" turns from "On" to "Off". Refer to REFERENCE VALUE .
Is the inspection result normal?

YES

INSPECTION END

NO

GO TO STEP 10 .

CHECK CONNECTOR AND TERMINAL
1. Turn the ignition switch OFF.
2. Disconnect ABS actuator and electric unit (control unit) harness connector.
3. Check the ABS actuator and electric unit (control unit) harness connector for disconnection or looseness.
4. Check the ABS actuator and electric unit (control unit) pin terminals for damage or loose connection with harness connector.
5. Disconnect brake pedal position switch harness connector.
6. Check the brake pedal position switch harness connector for disconnection or looseness.
7. Check the brake pedal position switch pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?

YES

GO TO STEP 12 .

NO

Repair / replace harness or connector, securely lock the connector, and GO TO STEP 11 .

CHECK DATA MONITOR (4)

With CONSULT
1. Connect ABS actuator and electric unit (control unit) harness connector.
2. Connect brake pedal position switch harness connector.
3. Erase self-diagnosis result for "ABS".
4. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
5. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
6. Select "ABS", "DATA MONITOR" and "STOP LAMP SW2" according to this order. Check that data monitor displays "On" or "Off" when brake pedal is depressed or released. Refer to REFERENCE VALUE .
7. Select "ABS", "DATA MONITOR" and "PRESS SENSOR" according to this order. Depress the brake pedal and check if "PRESSURE SENSOR" indicates "5 bar" or less when "STOP LAMP SW2" of "DATA MONITOR" turns from "On" to "Off". Refer to REFERENCE VALUE .
Is the inspection result normal?

YES

INSPECTION END

NO

Replace the ABS actuator and electric unit (control unit). Refer to REMOVAL AND INSTALLATION .

CHECK BRAKE PEDAL POSITION SWITCH CIRCUIT (1)

Turn the ignition switch OFF.
Disconnect ABS actuator and electric unit (control unit) harness connector.

Check the voltage between ABS actuator and electric unit (control unit) harness connector and ground.

+		-	Condition	Voltage
ABS actuator and electric unit (control unit)
Connector	Terminal
E24	6	Ground	Brake pedal depressed	Approx. 0 V
E24	6	Ground	Brake pedal not depressed	Approx. 0 V

Turn the ignition switch ON.
NOTE:
Never set the vehicle to READY/Never start the engine.

Check the voltage between ABS actuator and electric unit (control unit) harness connector and ground.

+		-	Condition	Voltage
ABS actuator and electric unit (control unit)
Connector	Terminal
E24	6	Ground	Brake pedal depressed	Approx. 0 V
E24	6	Ground	Brake pedal not depressed	10 - 16 V

Is the inspection result normal?

YES

Replace the ABS actuator and electric unit (control unit). Refer to REMOVAL AND INSTALLATION .

Repair / replace harness or connector, and GO TO STEP 13 .

CHECK BRAKE PEDAL POSITION SWITCH CIRCUIT (2)

Turn the ignition switch OFF.
Disconnect brake pedal position switch harness connector.

Check the continuity between ABS actuator and electric unit (control unit) harness connector and brake pedal position switch harness connector.

ABS actuator and electric unit (control unit)		Brake pedal position switch		Continuity
Connector	Terminal	Connector	Terminal	Continuity
E24	6	E43	2	Existed

Check the continuity between brake pedal position switch harness connector and stop lamp OFF relay 2 harness connector.

Brake pedal position switch		Stop lamp OFF relay 2		Continuity
Connector	Terminal	Connector	Terminal	Continuity
E43	2	T35	3	Existed

Check the continuity between ABS actuator and electric unit (control unit) harness connector and the ground.

ABS actuator and electric unit (control unit)		-	Continuity
Connector	Terminal	-	Continuity
E24	6	Ground	Not existed

Is the inspection result normal?

YES

Replace the ABS actuator and electric unit (control unit). Refer to REMOVAL AND INSTALLATION .

Repair / replace harness or connector, and GO TO STEP 14 .

CHECK DATA MONITOR (4)

With CONSULT
1. Connect ABS actuator and electric unit (control unit) harness connector.
2. Connect brake pedal position switch harness connector.
3. Erase self-diagnosis result for "ABS".
4. Turn the ignition switch OFF → ON → OFF.
  NOTE:
  Wait at least 10 seconds after turning ignition switch OFF or ON.
5. Set the vehicle to READY/Start the engine.
  NOTE:
  Stop the vehicle.
6. Select "ABS", "DATA MONITOR" and "STOP LAMP SW2" according to this order. Check that data monitor displays "On" or "Off" when brake pedal is depressed or released. Refer to REFERENCE VALUE .
7. Select "ABS", "DATA MONITOR" and "PRESS SENSOR" according to this order. Depress the brake pedal and check if "PRESSURE SENSOR" indicates "5 bar" or less when "STOP LAMP SW2" of "DATA MONITOR" turns from "On" to "Off". Refer to REFERENCE VALUE .
Is the inspection result normal?

YES

INSPECTION END

NO

Replace the ABS actuator and electric unit (control unit). Refer to REMOVAL AND INSTALLATION .