Nissan Maxima Service and Repair Manual: 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 those two types of input (ON/OFF signal).

Refer to EC-68, "System Diagram" 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 EC-391, "DTC Logic".
•  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 is turned OFF. And even when malfunction A is detected in two consecutive trips, DTC is not stored in ECM memory.

DTC CONFIRMATION PROCEDURE

1.PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.

NOTE: The procedure for malfunction B is not described. It takes an extremely long time to complete the procedure for malfunction B. By performing the procedure for malfunction A, the condition that causes malfunction B can be detected.

2.PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Start engine (VDC switch OFF).
2. Select "DATA MONITOR" mode with CONSULT.
3. Press MAIN switch and check that CRUISE lamp illuminate.
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.

5. Check 1st trip DTC.

With GST

Follow the procedure "With CONSULT" above.

3.PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Drive the vehicle for at least 5 consecutive seconds under the following conditions.

CAUTION: Always drive vehicle at a safe speed.

If a road test is expected to be easier, it is unnecessary to lift the vehicle.

2. Check 1st trip DTC.

With GST

Follow the procedure "With CONSULT" above.

Diagnosis Procedure

Regarding Wiring Diagram information, refer to EC-554, "Wiring Diagram".

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.

2.CHECK OVERALL FUNCTION-II

With CONSULT

Check "BRAKE SW2" indication in "DATA MONITOR" mode.

Without CONSULT

Check the voltage between ECM harness connectors.

3.CHECK ASCD BRAKE SWITCH POWER SUPPLY CIRCUIT

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.

4.DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector E6
• Junction block harness connectors E44, E46
• 10 A fuse (No. 3)
• Harness for open or short between ASCD brake switch and fuse

5.CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

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.

6.DETECT MALFUNCTIONING PART

Check the following.

• Junction block connectors E45, E46
• Harness for open or short between ASCD brake switch and ECM

7.CHECK ASCD BRAKE SWITCH

8.CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check the voltage between stop lamp switch harness connector and ground.

9.DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector E6
• 10 A fuse (No. 7)
• Harness for open or short between stop lamp switch and battery

10.CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

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.

11.DETECT MALFUNCTIONING PART

Check the following.

• Fuse block (J/B) connector E6
• Junction block connectors E44, E45
• Harness for open or short between stop lamp switch and ECM

12.CHECK STOP LAMP SWITCH

13.CHECK INTERMITTENT INCIDENT

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.

2.CHECK ASCD BRAKE SWITCH-II

1. Adjust ASCD brake switch installation. Refer to BR-18, "Removal and Installation".
2. Check the continuity between ASCD brake switch terminals under the following conditions.

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.

2.CHECK STOP LAMP SWITCH-II

1. Adjust stop lamp switch installation. Refer to BR-14, "Inspection and Adjustment".
2. Check harness continuity between stop lamp switch terminals under the following conditions.