Page 611 of 720

DTC P1572 ASCD BRAKE SWITCH
EC-611
C
D
E
F
G
H
I
J
K
L
MA
EC
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 613 of 720
DTC P1572 ASCD BRAKE SWITCH
EC-613
C
D
E
F
G
H
I
J
K
L
MA
EC
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 615 of 720

DTC P1572 ASCD BRAKE SWITCH
EC-615
C
D
E
F
G
H
I
J
K
L
MA
EC
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
Page 619 of 720

DTC P1572 ASCD BRAKE SWITCH
EC-619
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2006 November2007 350Z
12. CHECK STOP LAMP SWITCH
Refer to EC-624, "
Component Inspection"
OK or NG
OK >> GO TO 13.
NG >> Replace stop lamp switch.
13. CHECK INTERMITTENT INCIDENT
Refer to EC-141, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
M/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.
CONDITION INDICATION
Brake pedal and/or clutch pedal: Slightly depressed OFF
Brake pedal and clutch pedal: Fully released ON
CONDITION VOLTAGE
Brake pedal and/or clutch pedal: Slightly depressed Approximately 0V
Brake pedal and clutch pedal: Fully released Battery voltage
PBIB3577E
Page 620 of 720
EC-620
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 fol-
lowing conditions.
OK or NG
OK >> GO TO 16.
NG >> GO TO 11.
3. CHECK ASCD BRAKE SWITCH CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ASCD clutch switch harness connector.
3. Turn ignition switch ON.
4. Check voltage between ASCD clutch switch terminal 1 and
ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 8.
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
PBIB1282E
Voltage: Battery voltage
PBIB0799E
Page 624 of 720

EC-624
DTC P1572 ASCD BRAKE SWITCH
Revision: 2006 November2007 350Z
Component InspectionNBS000G6
ASCD BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Check continuity between ASCD brake switch terminals 1 and 2
under the following conditions.
If NG, adjust ASCD brake switch installation, refer to BR-7,
"BRAKE PEDAL" , and perform step 3 again.
ASCD CLUTCH SWITCH (M/T MODELS)
1. Turn ignition switch OFF.
2. Disconnect ASCD clutch switch harness connector.
3. Check continuity between ASCD clutch switch terminals 1 and 2
under the following conditions.
If NG, adjust ASCD clutch switch installation, refer to CL-5,
"CLUTCH PEDAL" , and perform step 3 again.
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check continuity between stop lamp switch terminals 3 and 4
under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-7,
"BRAKE PEDAL" , and perform step 3 again.
Condition Continuity
Brake pedal: Fully released Should exist
Brake pedal: Slightly depressed Should not exist
SEC023D
Condition Continuity
Clutch pedal: Fully released Should exist
Clutch pedal: Slightly depressed Should not exist
SEC024D
Condition Continuity
Brake pedal: Fully released Should not exist
Brake pedal: Slightly depressed Should exist
PBIB2310E
Page 628 of 720

EC-628
DTC P1805 BRAKE SWITCH
Revision: 2006 November2007 350Z
DTC P1805 BRAKE SWITCHPFP:25320
DescriptionNBS000GI
Brake switch signal is applied to the ECM through the stop lamp switch when the brake pedal is depressed.
This signal is used mainly to decrease the engine speed when the vehicle is driving.
CONSULT-III Reference Value in Data Monitor ModeNBS000GJ
Specification data are reference values.
On Board Diagnosis LogicNBS000GK
The MIL will not light up for this self-diagnosis.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureNBS000GL
WITH CONSULT-III
1. Turn ignition switch ON.
2. Fully depress the brake pedal for at least 5 seconds.
3. Erase the DTC with CONSULT-III.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to EC-630, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-III” above.
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW
Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1805
1805Brake switchA brake switch signal is not sent to ECM for
extremely long time while the vehicle is driving.
Harness or connectors
(The stop lamp switch circuit is open or
shorted.)
Stop lamp switch
Engine operating condition in fail-safe mode
ECM controls the electric throttle control actuator by regulating the throttle opening to a small range.
Therefore, acceleration will be poor.
Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration