Brake INFINITI FX35 2008 Service Manual

EC-474
< SERVICE INFORMATION >[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
DTC P1572 ASCD BRAKE SWITCH
Component DescriptionINFOID:0000000001326337
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-37
for the ASCD function.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326338
Specification data are reference values.
On Board Diagn osis LogicINFOID:0000000001326339
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 pe rform the trouble diagnosis for DTC P0605. Refer
to EC-422
This self-diagnosis has the one tr ip 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 igniti on switch OFF. And even when ma lfunction A is detected in two
consecutive trips, DTC is not stored in ECM memory.
DTC Confirmation ProcedureINFOID:0000000001326340
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
 If DTC Confirmation Procedure has been previously conduc ted, 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 procedur e for malfunction A, the incident that causes malfunction B can be
detected.
PBIB1605E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW1
(ASCD brake switch)  Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2
(Stop lamp switch)  Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No.
Trouble Diagnosis
Name DTC Detecting Condition Possible Cause
P1572
1572 ASCD brake switch A)
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
(Stop lamp switch circuit is shorted.)
 Harness or connectors (ASCD brake switch circuit is 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
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DTC P1572 ASCD BRAKE SWITCHEC-475
< SERVICE INFORMATION > [VQ35DE]
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TESTING CONDITION:
Steps 4 and 5 may be conducted with the drive wheels li
fted 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.
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.
If 1st trip DTC is detected, go to EC-477, "
Diagnosis Procedure".
If 1st trip DTC is not detected, go to the following step.
6. Drive the vehicle for at least 5 consecutive seconds under the following condition.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-477, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” 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 location Depress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned vehicle speed.
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EC-476
< SERVICE INFORMATION >[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
Wiring Diagram
INFOID:0000000001326341
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
TBWM1402E
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DTC P1572 ASCD BRAKE SWITCHEC-477
< SERVICE INFORMATION > [VQ35DE]
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Diagnosis ProcedureINFOID:0000000001326342
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 108 and ground under the following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK OVERALL FUNCTION-II
With CONSULT-III
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-III
Check voltage between ECM terminal 101 and ground under the following conditions.
TER-
MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
101 P/L Stop lamp switch [Ignition switch: OFF]
 Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]
 Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
108 SB ASCD brake switch [Ignition switch: ON]
 Brake pedal: Slightly depressed
Approximately 0V
[Ignition switch: ON]
 Brake pedal: Fully released BATTERY 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
MBIB0061E
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
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EC-478
< SERVICE INFORMATION >[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
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.
4.DETECT MALFUNCTIONING PART
Check the following.
 Fuse block (J/B) connector E201
 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.
5.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 108 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 7.
NG >> GO TO 6.
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
MBIB0060E
PBIB1605E
Voltage: Battery voltage
PBIB0857E
Continuity should exist.
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DTC P1572 ASCD BRAKE SWITCHEC-479
< SERVICE INFORMATION > [VQ35DE]
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6.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E211, M41
 Harness for open or short between ECM and ASCD brake switch
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK ASCD BRAKE SWITCH
Refer to EC-480, "
Component Inspection"
OK or NG
OK >> GO TO 13.
NG >> Replace ASCD brake switch.
8.CHECK STOP LAMP SWIT CH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect stop lamp switch harness connector.
3. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 10.
NG >> GO TO 9.
9.DETECT MALFUNCTIONING PART
Check the following.
 Fuse block (J/B) connector E201
 10A fuse
 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.
10.CHECK STOP LAMP SWITCH INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 101 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 12.
PBIB1605E
Voltage: Battery voltage
PBIB1184E
Continuity should exist.
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EC-480
< SERVICE INFORMATION >[VQ35DE]
DTC P1572 ASCD BRAKE SWITCH
NG >> GO TO 11.
11 .DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E211, M41
 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-480, "
Component Inspection"
OK or NG
OK >> GO TO 13.
NG >> Replace stop lamp switch.
13.CHECK INTERMITTENT INCIDENT
Refer to EC-139
.
>> INSPECTION END
Component InspectionINFOID:0000000001326343
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-5
, 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 1 and 2 under the following conditions.
If NG, adjust stop lamp switch installation, refer to BR-5
, and
perform step 3 again.
Condition Continuity
Brake pedal: Fully released Should exist
Brake pedal: Slightly depressed Should not exist
SEC023D
Condition Continuity
Brake pedal: Fully released Should not exist
Brake pedal: Slightly depressed Should exist
PBIB1185E
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EC-486
< SERVICE INFORMATION >[VQ35DE]
DTC P1805 BRAKE SWITCH
DTC P1805 BRAKE SWITCH
DescriptionINFOID:0000000001326356
Brake switch signal is applied to the ECM through t
he 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 ModeINFOID:0000000001326357
Specification data are reference values.
On Board Diagn osis LogicINFOID:0000000001326358
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 ProcedureINFOID:0000000001326359
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
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-488, "
Diagnosis Procedure".
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW  Ignition switch: ON Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1805
1805 Brake switch A brake switch signal is not sent to ECM for ex-
tremely long time while the vehicle is driving.  Harness or connectors
(Stop lamp switch circuit is open or short-
ed.)
 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
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DTC P1805 BRAKE SWITCHEC-487
< SERVICE INFORMATION > [VQ35DE]
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Wiring DiagramINFOID:0000000001326360
Specification data are reference values
and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals wh en measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
TBWM1403E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-488
< SERVICE INFORMATION >[VQ35DE]
DTC P1805 BRAKE SWITCH
Diagnosis Procedure
INFOID:0000000001326361
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 SWIT CH POWER SUPPLY CIRCUIT
1. Disconnect stop lamp switch harness connector.
2. Check voltage between stop lamp switch terminal 1 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
 10A fuse
 Fuse block (J/B) connector E201
 Harness for open and short between stop lamp switch and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
TER-MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
101 P/L Stop lamp switch [Ignition switch: OFF]
 Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]
 Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
Brake pedal Stop lamp
Fully released Not illuminated
Slightly depressed Illuminated
PBIB1605E
Voltage: Battery voltage
PBIB1184E
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