Page 609 of 720
DTC P1564 ASCD STEERING SWITCH
EC-609
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Revision: 2006 November2007 350Z
Component InspectionNBS000FZ
ASCD STEERING SWITCH
1. Disconnect combination switch (spiral cable) harness connector M203.
2. Check continuity between combination switch harness connec-
tor terminals 14 and 15 with pushing each switch.
3. If NG, replace ASCD steering switch.
Switch Condition Resistance [Ω]
MAIN switchPressed Approx. 0
Released Approx. 4,000
CANCEL switchPressed Approx. 250
Released Approx. 4,000
RESUME/ACCELERATE
switchPressed Approx. 1,480
Released Approx. 4,000
SET/COAST switchPressed Approx. 660
Released Approx. 4,000
PBIB2549E
Page 610 of 720

EC-610
DTC P1572 ASCD BRAKE SWITCH
Revision: 2006 November2007 350Z
DTC P1572 ASCD BRAKE SWITCHPFP:25320
Component DescriptionNBS000G0
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 EC-30, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)"
for the ASCD function.
CONSULT-III Reference Value in Data Monitor ModeNBS000G1
Specification data are reference values.
On Board Diagnosis LogicNBS000G2
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-512, "
DTC P0605 ECM".
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.
PBIB1282E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW1
(ASCD brake switch)
Ignition switch: ON
Brake pedal: Fully released (A/T)
Brake pedal and clutch pedal: Fully
released (M/T)ON
Brake pedal: Slightly depressed (A/T)
Brake pedal and/or clutch pedal:
Slightly depressed (M/T)OFF
BRAKE SW2
(Stop lamp switch)
Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1572
1572ASCD brake switchA)When the vehicle speed is above 30km/h
(19 MPH), ON signals from the stop lamp
switch and the ASCD brake switch are sent
to ECM at the same time.
Harness or connectors
(The stop lamp switch circuit is shorted.)
Harness or connectors
(The ASCD brake switch circuit is shorted.)
Harness or connectors
(The ASCD clutch switch circuit is shorted.)
(M/T models)
Stop lamp switch
ASCD brake switch
ASCD clutch switch (M/T models)
Incorrect stop lamp switch installation
Incorrect ASCD brake switch installation
Incorrect ASCD clutch switch installation
(M/T models)
ECM B)ASCD brake switch signal is not sent to
ECM for extremely long time while the vehi-
cle is driving
Page 611 of 720

DTC P1572 ASCD BRAKE SWITCH
EC-611
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Revision: 2006 November2007 350Z
DTC Confirmation ProcedureNBS000G3
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait
at least 10 seconds before conducting the next test.
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.
TESTING CONDITION:
Steps 4 and 5 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.
WITH CONSULT-III
1. Start engine (VDC switch or TCS switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-III.
3. Press MAIN switch and make sure that CRUISE indicator lights up.
4. Drive the vehicle for at least 5 consecutive seconds under the following condition.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-615, "
Diagnostic Procedure" .
If 1st trip DTC is not detected, go to the following step.
7. Drive the vehicle for at least 5 consecutive seconds under the following condition.
8. Check 1st trip DTC.
9. If 1st trip DTC is detected, go to EC-615, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Shift lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Shift lever Suitable position
Driving locationDepress the brake pedal for more than five seconds
so as not to come off from the above-mentioned
vehicle speed.
Page 612 of 720
EC-612
DTC P1572 ASCD BRAKE SWITCH
Revision: 2006 November2007 350Z
Wiring Diagram NBS000G4
A/T MODELS
TBWT1661E
Page 613 of 720
DTC P1572 ASCD BRAKE SWITCH
EC-613
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Revision: 2006 November2007 350Z
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
122 P/L Stop lamp switch[Ignition switch: OFF]
Brake pedal: Fully released0V
[Ignition switch: OFF]
Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
126 L/OR ASCD brake switch[Ignition switch: ON]
Brake pedal: Slightly depressed0V
[Ignition switch: ON]
Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
Page 614 of 720
EC-614
DTC P1572 ASCD BRAKE SWITCH
Revision: 2006 November2007 350Z
M/T MODELS
TBWT1662E
Page 615 of 720

DTC P1572 ASCD BRAKE SWITCH
EC-615
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Revision: 2006 November2007 350Z
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureNBS000G5
A/T MODELS
1. CHECK OVERALL FUNCTION-I
With CONSULT-III
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-III.
3. Check “BRAKE SW1” indication under the following conditions.
Without CONSULT-III
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 126 and ground under the
following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
122 P/L Stop lamp switch[Ignition switch: OFF]
Brake pedal: Fully released0V
[Ignition switch: OFF]
Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
126 L/OR ASCD brake switch[Ignition switch: ON]
Brake pedal and/or clutch pedal: Slightly
depressed0V
[Ignition switch: ON]
Brake pedal and clutch pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
CONDITION VOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
PBIB3577E
Page 616 of 720
EC-616
DTC P1572 ASCD BRAKE SWITCH
Revision: 2006 November2007 350Z
2. CHECK OVERALL FUNCTION-II
With CONSULT-III
1. Select “BRAKE SW2” in “DATA MONITOR” mode with CONSULT-III.
2. Check “BRAKE SW2” indication under the following conditions.
Without CONSULT-III
Check voltage between ECM terminal 122 and ground under the following conditions.
OK or NG
OK >> GO TO 13.
NG >> GO TO 8.
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 voltage between ASCD brake switch terminal 1 and
ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB3578E
PBIB1089E
Voltage: Battery voltage
PBIB0857E