Engine Controls
P1572 ASCD BRAKE SWITCH
Description
When the brake pedal is depressed, ASCD brake switch is turned OFF and stop lamp switch is turned ON.
ECM detects the state of the brake pedal by this input of two kinds (ON/OFF signal).
Refer to "AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System Description" System Description for the ASCD function.
DTC Logic
DTC DETECTION LOGIC
NOTE:
-If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to "DTC Logic" P0605.
-This self-diagnosis has the one trip detection logic. When malfunction A is detected, DTC is not stored in ECM memory. And in that case, 1st trip DTC and 1st trip freeze frame data are displayed.
1st trip DTC is erased when ignition switch OFF. And even when malfunction A is detected in two consecutive trips, DTC is not stored in ECM memory.
DTC CONFIRMATION PROCEDURE
1. INSPECTION START
Do you have CONSULT?
Do you have CONSULT?
YES- GO TO 2.
NO- GO TO 5.
2. PRECONDITIONING
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at least 10 seconds before conducting the next test.
NOTE:
Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for malfunction B. By performing procedure for malfunction A, the incident that causes malfunction B can be detected.
- GO TO 3.
3. PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A-I
1.Start engine (VDC switch OFF).
2.Select "DATA MONITOR" mode with CONSULT.
3.Press MAIN switch and make sure that CRUISE lamp lights up.
4.Drive the vehicle for at least 5 consecutive seconds under the following conditions.
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheels lifted in the shop or by driving the vehicle.
If a road test is expected to be easier, it is unnecessary to lift the vehicle.
Revision: March 20122013 Infiniti JX
5.Check 1st trip DTC.
Is 1st trip DTC detected?
YES- Go to "Diagnosis Procedure" .
NO- GO TO 4.
4. PERFORM DTC CONFIRMATION PROCEDURE A-II
1.Drive the vehicle for at least 5 consecutive seconds under the following conditions.
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheels lifted in the shop or by driving the vehicle.
If a road test is expected to be easier, it is unnecessary to lift the vehicle.
2.Check 1st trip DTC.
Is 1st trip DTC detected?
YES- Go to "Diagnosis Procedure" .
NO- INSPECTION END
5. PERFORM COMPONENT FUNCTION CHECK
Perform component function check. Refer to "Component Function Check" .
NOTE:
Use component function check to check the overall function of ASCD brake switch. During this check, a DTC
might not be confirmed.
Is the inspection result normal?
YES- INSPECTION END
NO- Go to "Diagnosis Procedure" .
Component Function Check
1. PERFORM COMPONENT FUNCTION CHECK
1.Turn ignition switch ON.
2.Check the voltage between ECM harness connectors.
Is the inspection result normal?
YES- INSPECTION END
NO- GO TO 2.
2. PERFORM COMPONENT FUNCTION CHECK-II
Check the voltage between ECM harness connectors.
Revision: March 20122013 Infiniti JX
Is the inspection result normal?
YES- INSPECTION END
NO- Go to "Diagnosis Procedure" .
Diagnosis Procedure
1. CHECK OVERALL FUNCTION-I
With CONSULT
1.Turn ignition switch ON.
2.Select "BRAKE SW1" in "DATA MONITOR" mode with CONSULT.
3.Check "BRAKE SW1" indication under the following conditions.
Without CONSULT
1.Turn ignition switch ON.
2.Check the voltage between ECM harness connectors.
Is the inspection result normal?
YES- GO TO 2.
NO- GO TO 3.
2. CHECK OVERALL FUNCTION-II
With CONSULT
Check "BRAKE SW2" indication in "DATA MONITOR" mode.
Without CONSULT
Check the voltage between ECM harness connectors.
Revision: March 20122013 Infiniti JX
Is the inspection result normal?
YES- Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
NO- GO TO 6.
3. CHECK ASCD BRAKE SWITCH POWER SUPPLY
1.Turn ignition switch OFF.
2.Disconnect ASCD brake switch harness connector.
3.Turn ignition switch ON.
4.Check the voltage between ASCD brake switch harness connector and ground.
Is the inspection result normal?
YES- GO TO 4.
NO- Repair or replace error-detected parts.
4. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT
1.Turn ignition switch OFF.
2.Disconnect ECM harness connector.
3.Check the continuity between ASCD brake switch harness connector and ECM harness connector.
4.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 5.
NO- Repair open circuit, short to ground or short to power in harness or connectors.
5. CHECK ASCD BRAKE SWITCH
Check ASCD brake switch. Refer to "Component Inspection (ASCD Brake Switch)" .
Is the inspection result normal?
YES- Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
NO- Replace ASCD brake switch. Refer to "Exploded View" Exploded View.
6. CHECK STOP LAMP SWITCH POWER SUPPLY
1.Turn ignition switch OFF.
2.Disconnect stop lamp switch harness connector.
3.Check the voltage between stop lamp switch harness connector and ground.
Is the inspection result normal?
Revision: March 20122013 Infiniti JX
YES- GO TO 7.
NO- Perform the trouble diagnosis for power supply circuit.
7. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT
1.Disconnect ECM harness connector.
2.Check the continuity between stop lamp switch harness connector and ECM harness connector.
3.Also check harness for short to ground and short to power.
Is the inspection result normal?
YES- GO TO 8.
NO- Repair or replace error-detected parts.
8. CHECK STOP LAMP SWITCH
Check stop lamp switch. Refer to "Component Inspection (Stop Lamp Switch)" .
Is the inspection result normal?
YES- Check intermittent incident. Refer to "Intermittent Incident" Intermittent Incident.
NO- Replace stop lamp switch. Refer to "Exploded View" Exploded View.
Component Inspection (ASCD Brake Switch)
1. CHECK ASCD BRAKE SWITCH-I
1.Turn ignition switch OFF.
2.Disconnect ASCD brake switch harness connector.
3.Check the continuity between ASCD brake switch terminals under the following conditions.
Is the inspection result normal?
YES- INSPECTION END
NO- GO TO 2.
2. CHECK ASCD BRAKE SWITCH-II
1.Adjust ASCD brake switch installation. Refer to "Adjustment" Adjustments.
2.Check the continuity between ASCD brake switch terminals under the following conditions.
Is the inspection result normal?
YES- INSPECTION END
NO- Replace ASCD brake switch. Refer to "Exploded View" Exploded View.
Component Inspection (Stop Lamp Switch)
1. CHECK STOP LAMP SWITCH-I
1.Turn ignition switch OFF.
2.Disconnect stop lamp switch harness connector.
3.Check harness continuity between stop lamp switch terminals under the following conditions.
Revision: March 20122013 Infiniti JX
Is the inspection result normal?
YES- INSPECTION END
NO- GO TO 2.
2. CHECK STOP LAMP SWITCH-II
1.Adjust stop lamp switch installation. Refer to "Adjustment" Adjustments.
2.Check harness continuity between stop lamp switch terminals under the following conditions.
Is the inspection result normal?
YES- INSPECTION END
NO- Replace stop lamp switch. Refer to "Exploded View" Exploded View.
Revision: March 20122013 Infiniti JX