2004 INFINITI FX35 brake light

DTC P1572 ASCD BRAKE SWITCH
EC-1199
[VK45DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2004 November 2004 FX35/FX45
DTC P1572 ASCD BRAKE SWITCHPFP:25320
Component DescriptionABS00CCF
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-1334, "
AUTOMATIC SPEED CONTROL DEVICE
(ASCD)" for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeABS00CCG
Specification data are reference values.
On Board Diagnosis LogicABS00CCH
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:

If DTC P 1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-1057
.

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.
PBIB1506E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW 1
(ASCD brake switch)

Ignition switch: ON
Brake pedal: Fully released ON

Brake pedal: Slightly depressed OFF
BRAKE SW 2
(stop lamp switch)

Ignition switch: ON
Brake 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 30 km/h
(19 MPH), ON signals from the stop lamp
switch and the ASCD brake switch are
sent to the ECM at the same time.
Harness or connectors
(The stop lamp switch circuit is open or
shorted.)

Harness or connectors
(The ASCD brake switch circuit is open or
shorted.)

Stop lamp switch

ASCD brake switch

Incorrect stop lamp switch installation

Incorrect ASCD brake switch installation

ECM B)

ASCD brake switch signal is not sent to
ECM for extremely long time while the
vehicle is driving.

EC-1200
[VK45DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2004 November 2004 FX35/FX45
DTC Confirmation ProcedureABS00CCI
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 3 and 4 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 (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
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 conditions.
If 1st trip DTC is detected, go to EC-1202, "
Diagnostic Proce-
dure" .
If 1st trip DTC is not detected, go to the following step.
5. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
6. If 1st trip DTC is detected, go to EC-1202, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector 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.
PBIB2386E

EC-1202
[VK45DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2004 November 2004 FX35/FX45
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 ProcedureABS00CCK
1. CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-II.
3. Check “BRAKE SW1” indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 108 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)
101 P/L Stop lamp switch[Ignition switch: OFF]

Brake pedal: Fully releasedApproximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
108 SB ASCD brake switch[Ignition switch: ON]

Brake pedal: Slightly depressedApproximately 0V
[Ignition switch: ON]

Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
When brake pedal is slightly depressed OFF
When brake pedal is fully released ON
SEC011D
CONDITION VOLTAGE
When brake pedal is slightly depressed Approximately 0V
When brake pedal is fully released Battery voltage
MBIB0061E

DTC P1572 ASCD BRAKE SWITCH
EC-1203
[VK45DE]
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: 2004 November 2004 FX35/FX45
2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the following conditions.
OK or NG
OK >> GO TO 13.
NG >> GO TO 8.
CONDITION INDICATION
When brake pedal is fully released OFF
When brake pedal is slightly depressed ON
SEC013D
CONDITION VOLTAGE
When brake pedal is fully released Approximately 0V
When brake pedal is slightly depressed Battery voltage
PBIB1537E

EC-1206
[VK45DE]
DTC P1572 ASCD BRAKE SWITCH
Revision: 2004 November 2004 FX35/FX45
11 . DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E211, M41

Joint connector-2

Harness for open or short between ECM and stop lamp switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
12. CHECK STOP LAMP SWITCH
Refer to EC-1206, "
Component Inspection"
OK or NG
OK >> GO TO 13.
NG >> Replace stop lamp switch.
13. CHECK INTERMITTENT INCIDENT
Refer to EC-784, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionABS00CCL
ASCD BRAKE SWITCH
1. Turn ignition switch OFF.
2. Disconnect ASCD brake switch harness connector.
3. Check harness 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.
STOP LAMP SWITCH
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check harness 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
When brake pedal is fully released. Should exist.
When brake pedal is slightly depressed. Should not exist.
PBIB1536E
Condition Continuity
When brake pedal is fully released. Should not exist.
When brake pedal is slightly depressed. Should exist.
PBIB1535E

EC-1216
[VK45DE]
DTC P1720 VEHICLE SPEED SENSOR (A/T OUTPUT)
Revision: 2004 November 2004 FX35/FX45
DTC P1720 VEHICLE SPEED SENSOR (A/T OUTPUT)PFP:31036
DescriptionABS00CD1
NOTE:
If DTC P1720 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-792, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from “unified meter
and A/C amp.”, and the other is from TCM (Transmission control module). ECM uses these two signals for
engine control.
CONSULT-II Reference Value in Data Monitor ModeABS00CD2
Specification data are reference values.
On Board Diagnosis LogicABS00CD3
The MIL will not light up for this diagnosis.
DTC Confirmation ProcedureABS00CD4
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.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine.
4. Drive vehicle at a speed of 20 km/h (12 MPH) or more for at least 5 seconds without brake pedal depress-
ing.
5. If 1st trip DTC is detected, go to EC-1217, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
MONITOR ITEM CONDITION SPECIFICATION
VEH SPEED SE

Turn drive wheels and compare the CONSULT-II value with speedometer
indicationAlmost the same speed as the
speedometer indication
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1720
1720Vehicle speed sensor
(A/T output)ECM detects a difference between two
vehicle speed sensor signals is out of the
specified range.

Harness or connectors
(The CAN communication line is open or
shorted)

Harness or connectors
(Revolution sensor circuit is open or shorted)

Harness or connectors
(Wheel sensor circuit is open or shorted.)

TCM

ABS actuator and electric unit (control unit)

Unified meter and A/C amp.

EC-1220
[VK45DE]
DTC P1805 BRAKE SWITCH
Revision: 2004 November 2004 FX35/FX45
DTC P1805 BRAKE SWITCHPFP:25320
DescriptionABS00CDA
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-II Reference Value in Data Monitor ModeABS00CDB
Specification data are reference values.
On Board Diagnosis LogicABS00CDC
The MIL will not light up for this diagnosis.
FAIL-SAFE MODE
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureABS00CDD
WITH CONSULT-II
1. Turn ignition switch ON.
2. Fully depress the brake pedal for at least 5 seconds.
3. Erase the DTC with CONSULT-II.
4. Select “DATA MONITOR” mode with CONSULT-II.
5. If 1st trip DTC is detected, go to EC-1222, "
Diagnostic Proce-
dure" .
WITH GST
Follow the procedure “WITH CONSULT-II” 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
(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
SEF058Y

EC-1222
[VK45DE]
DTC P1805 BRAKE SWITCH
Revision: 2004 November 2004 FX35/FX45
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 ProcedureABS00CDF
1. CHECK STOP LAMP SWITCH CIRCUIT
1. Turn ignition switch OFF.
2. Check the stop lamp when depressing and releasing the brake pedal.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK STOP LAMP SWITCH POWER SUPPLY CIRCUIT
1. Disconnect stop lamp switch harness connector.
2. Check voltage between stop lamp switch terminal 1 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101 P/L Stop lamp switch[Ignition switch: OFF]

Brake pedal: Fully releasedApproximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
Brake pedal Stop lamp
Fully released Not illuminated
Slightly depressed Illuminated
PBIB1506E
Voltage: Battery voltage
PBIB1184E