Page 1645 of 2896

EC-476Revision: June 2006
DTC P1572 ASCD BRAKE SWITCH
2007 Versa
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 ProcedureUBS00QLR
1. CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CON-
SULT-II.
3. Check “BRAKE SW1” indication under the following conditions.
M/T models
A/T and CVT models
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 100 and ground under the
following conditions.
M/T models
A/T and CVT models
OK or NG
OK >> GO TO 2.
NG (M/T models) >>GO TO 3.
NG (A/T and CVT models) >>GO TO 4.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
99 R Stop lamp switch[Ignition switch: ON]
Brake pedal: Fully releasedApproximately 0V
[Ignition switch: ON]
Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
100 G ASCD brake switch
Brake pedal: Slightly depressed (A/T, CVT)
Brake pedal and clutch pedal: Fully released
(M/T) Approximately 0V
Brake pedal: Slightly depressed (A/T, CVT)
Brake pedal and/or clutch pedal: Slightly
depressed (M/T)BATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
Clutch pedal and/or brake pedal: Slightly depressed OFF
Clutch pedal and brake pedal: Fully released ON
CONDITION INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
CONDITION VOLTAGE
Clutch pedal and/or brake pedal: Slightly depressed Approximately 0V
Clutch pedal and brake pedal: Fully released Battery voltage
CONDITION VOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
SEC0 11D
PBIB3315E
Page 1646 of 2896
DTC P1572 ASCD BRAKE SWITCH
EC-477
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2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-II
Check voltage between ECM terminal 99 and ground under the fol-
lowing conditions.
OK or NG
OK >> GO TO 15.
NG >> GO TO 11.
3. CHECK ASCD CLUTCH SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ASCD clutch switch (1) harness connector.
–Clutch pedal (2)
3. Turn ignition switch ON.
4. Check voltage between ASCD clutch switch terminal 1 and
ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 9.
NG >> GO TO 4.
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
SEC0 13 D
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB0 311 E
BBIA0709E
Voltage: Battery voltage
PBIB0857E
Page 1647 of 2896

EC-478Revision: June 2006
DTC P1572 ASCD BRAKE SWITCH
2007 Versa
4. CHECK ASCD BRAKE SWITCH POWER SUPPLY
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch (2) harness connector.
–Stop lamp switch (1)
3. Turn ignition switch ON.
4. Check voltage between ASCD brake switch terminal 1 and
ground under the following conditions with CONSULT-II or
tester.
OK or NG
OK (M/T models) >>GO TO 6.
OK (A/T and CVT models) >>GO TO 7.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M69, E7
10A fuse
Harness for open or short between ASCD brake switch and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
6. CHECK ASCD CLUTCH SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Check harness continuity between ASCD brake switch terminal 2 and ASCD clutch switch terminal 1.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
BBIA0708E
CONDITION VOLTAGE
Clutch pedal: Fully released Battery voltage
Clutch pedal: Slightly depressed Approx. 0V
PBIB0857E
Continuity should exist.
Page 1648 of 2896

DTC P1572 ASCD BRAKE SWITCH
EC-479
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7. CHECK ASCD BRAKE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 100 and ASCD brake switch terminal 2.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK ASCD BRAKE SWITCH
Refer to EC-481, "
Component Inspection" .
OK or NG
OK >> GO TO 15.
NG >> Replace ASCD brake switch.
9. CHECK ASCD CLUTCH SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 100 and ASCD clutch switch terminal 2.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 10.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
10. CHECK ASCD CLUTCH SWITCH
Refer to EC-481, "
Component Inspection"
OK or NG
OK >> GO TO 15.
NG >> Replace ASCD clutch switch.Continuity should exist.
Continuity should exist.
Page 1649 of 2896

EC-480Revision: June 2006
DTC P1572 ASCD BRAKE SWITCH
2007 Versa
11 . CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch (1) harness connector.
–ASCD brake switch (2)
3. Check voltage between stop lamp switch terminal 1 and ground with CONSULT -II or tester.
OK or NG
OK >> GO TO 13.
NG >> GO TO 12.
12. DETECT MALFUNCTIONING PART
Check the following.
Harness connectors M69, E7
Harness for open or short between stop lamp switch and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
13. CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 99 and stop lamp switch terminal 2.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 14.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
BBIA0708E
Voltage: Battery voltage
PBIB3317E
Continuity should exist.
Page 1650 of 2896

DTC P1572 ASCD BRAKE SWITCH
EC-481
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14. CHECK STOP LAMP SWITCH
Refer to EC-481, "
Component Inspection"
OK or NG
OK >> GO TO 15.
NG >> Replace stop lamp switch.
15. CHECK INTERMITTENT INCIDENT
Refer to EC-143, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00QLS
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-6,
"BRAKE PEDAL" , and perform step 3 again.
ASCD CLUTCH SWITCH
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.
Condition Continuity
Brake pedal: Fully released. Should exist.
Brake pedal: Slightly depressed. Should not exist.
SEC0 23 D
Condition Continuity
Clutch pedal: Fully released. Should exist.
Clutch pedal: Slightly depressed. Should not exist.
SEC0 23 D
Page 1651 of 2896
EC-482Revision: June 2006
DTC P1572 ASCD BRAKE SWITCH
2007 Versa
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check continuity between stop lamp switch terminals 1 and 2 under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-6, "
BRAKE PEDAL" , and perform step 3 again.
Condition Continuity
Brake pedal: Fully released. Should not exist.
Brake pedal: Slightly depressed. Should exist.
PBIB3318E
Page 1652 of 2896

DTC P1574 ASCD VEHICLE SPEED SENSOR
EC-483
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DTC P1574 ASCD VEHICLE SPEED SENSORPFP:31036
Component DescriptionUBS00QLT
The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combina-
tion meter, and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD
control. Refer to EC-28, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for ASCD functions.
On Board Diagnosis LogicUBS00QLU
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:
If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-151, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010.
Refer to EC-154, "
DTC U1010 CAN COMMUNICATION" .
If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500.
Refer to EC-421, "
DTC P0500 VSS"
If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-427, "
DTC P0605 ECM"
DTC Confirmation ProcedureUBS00QLV
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.
TESTING CONDITION:
Step 3 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-II
1. Start engine.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25MPH).
4. If DTC is detected, go to EC-484, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1574
1574ASCD vehicle speed
sensorECM detects a difference between two vehicle
speed signals is out of the specified range.
Harness or connectors
(CAN communication line is open or shorted.)
Harness or connectors
(Combination meter circuit is open or
shorted.)
TCM (A/T and CVT models)
Combination meter
Wheel sensor
ECM
SEF 0 58 Y