ignition INFINITI QX56 2007 Factory Service Manual

DTC P1574 ICC VEHICLE SPEED SENSOR
EC-535
< SERVICE INFORMATION >
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DTC P1574 ICC VEHICLE SPEED SENSOR
Component DescriptionINFOID:0000000003532070
The ECM receives two vehicle speed signals via CAN communication line. One is sent from “unified meter and
A/C amp.”, and the other is from TCM (Transmission control module). The ECM uses these signals for ICC
control. Refer to ACS-6
for ICC functions.
On Board Diagnosis LogicINFOID:0000000003532071
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-145
.
•If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
•If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-429
.
•If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532072
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-536, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1574
1574ICC vehicle speed sensorECM detects a difference between two vehicle
speed signals is out of the specified range.• Harness or connectors
(The CAN communication line is open or
shorted.)
• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
•TCM
•ECM
SEF058Y

DTC P1574 ASCD VEHICLE SPEED SENSOR
EC-537
< SERVICE INFORMATION >
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DTC P1574 ASCD VEHICLE SPEED SENSOR
Component DescriptionINFOID:0000000003532074
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-30
for ASCD functions.
On Board Diagnosis LogicINFOID:0000000003532075
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-145
.
•If DTC P1574 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
•If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-429
.
•If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532076
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 (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25 MPH).
4. If DTC is detected, go to EC-538, "
Diagnosis 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
(The CAN communication line is open or
shorted.)
• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
•TCM
•ECM
SEF058Y

DTC P1805 BRAKE SWITCH
EC-539
< SERVICE INFORMATION >
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DTC P1805 BRAKE SWITCH
DescriptionINFOID:0000000003532078
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 ModeINFOID:0000000003532079
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532080
The MIL will not light up for this self-diagnosis.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000003532081
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-541, "
Diagnosis Procedure".
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 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
SEF058Y

DTC P1805 BRAKE SWITCH
EC-541
< SERVICE INFORMATION >
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Diagnosis ProcedureINFOID:0000000003532083
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 3 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors M31, E152
• Fuse block (J/B) connector M60
• 10A fuse
• 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.
TER-
MI-
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NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101 R/W 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
BBIA0373E
Voltage: Battery voltage
PBIB2102E

EC-542
< SERVICE INFORMATION >
DTC P1805 BRAKE SWITCH
4.CHECK STOP LAMP 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 101 and stop lamp switch terminal 4.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK STOP LAMP SWITCH
Refer to EC-542, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace stop lamp switch.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
>>INSPECTION END
Component InspectionINFOID:0000000003532084
STOP LAMP SWITCH
1. Disconnect stop lamp switch harness connector.
2. Check continuity between stop lamp switch terminals 3 and 4
under the following conditions.
3. If NG, adjust stop lamp switch installation, refer to BR-5
, and
perform step 2 again.Continuity should exist.
BBIA0373E
Conditions Continuity
Brake pedal: Fully released Should not exist.
Brake pedal: Slightly depressed Should exist.
PBIB2103E

DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
EC-543
< SERVICE INFORMATION >
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DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
Component DescriptionINFOID:0000000003532085
Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle
control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends
an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition
switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not
provided to the ECM.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532086
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532087
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MlL lights up.
DTC Confirmation ProcedureINFOID:0000000003532088
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 DTC P2100
With CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR””mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-546, "
Diagnosis Procedure" .
MONITOR ITEM CONDITION SPECIFICATION
THRTL RELAY • Ignition switch: ON ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2100
2100Throttle control motor
relay circuit openECM detects a voltage of power source for
throttle control motor is excessively low.• Harness or connectors
(Throttle control motor relay circuit is
open)
• Throttle control motor relay
P2103
2103Throttle control motor
relay circuit shortECM detect the throttle control motor relay is
stuck ON.• Harness or connectors
(Throttle control motor relay circuit is
shorted)
• Throttle control motor relay
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF058Y

EC-544
< SERVICE INFORMATION >
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
With GST
Follow the procedure “With CONSULT-II” above.
PROCEDURE FOR DTC P2103
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V.
With CONSULT-II
1. Turn ignition switch ON and wait at least 1 second.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. If DTC is detected, go to EC-546, "
Diagnosis Procedure" .
With GST
Follow the procedure “With CONSULT-II” above.
SEF058Y

EC-546
< SERVICE INFORMATION >
DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000003532090
1.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Check voltage between ECM terminal 104 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-II
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E122.
3. Check continuity between ECM terminal 104 and IPDM E/R terminal 47.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
TER-
MI-
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NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
3LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4L/WThrottle control motor
(Close)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Released0 - 14V
5L/BThrottle control motor
(Open)[Ignition switch: ON]
• Engine: Stopped
• Selector lever: D
• Accelerator pedal: Fully depressed0 - 14V
104 O Throttle control motor relay[Ignition switch: OFF]BATTERY VOLTAGE
(11 - 14V)
[Ignition switch: ON]0 - 1.0V
PBIB1104E
PBIB1105E
Voltage: Battery voltage
PBIB1171E
Continuity should exist.

DTC P2100, P2103 THROTTLE CONTROL MOTOR RELAY
EC-547
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3.CHECK FUSE
1. Disconnect 20A fuse.
2. Check 20A fuse for blown.
OK or NG
OK >> GO TO 7.
NG >> Replace 20A fuse.
4.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
Check voltage between ECM terminal 3 and ground under the fol-
lowing conditions with CONSULT-II or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 5.
5.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect IPDM E/R harness connector E119.
4. Check continuity between ECM terminal 3 and IPDM E/R terminal 6.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E2, F32
• Harness for open or short between ECM and IPDM E/R
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK INTERMITTENT INCIDENT
Refer to EC-138
.
OK or NG
OK >> Replace IPDM E/R. Refer to PG-28, "Removal and Installation of IPDM E/R" .
NG >> Repair or replace harness or connectors.
Ignition switch Voltage
OFF Approximately 0V
ONBattery voltage
(11 - 14V)
MBIB0028E
Continuity should exist.

EC-548
< SERVICE INFORMATION >
DTC P2101 ELECTRIC THROTTLE CONTROL FUNCTION
DTC P2101 ELECTRIC THROTTLE CONTROL FUNCTION
DescriptionINFOID:0000000003532091
NOTE:
If DTC P2101 is displayed with DTC P2100 or 2119, first perform the trouble diagnosis for DTC P2100
or P2119. Refer to EC-543
or EC-559 .
Electric throttle control actuator consists of throttle control motor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicINFOID:0000000003532092
This self-diagnosis has the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000003532093
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:
Before performing the following procedure, confirm that battery voltage is more than 11V when engine
is running.
WITH CONSULT-II
1. Turn ignition switch ON and wait at least 2 seconds.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and let it idle for 5 seconds.
4. If DTC is detected, go to EC-550, "
Diagnosis Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2101
2101Electric throttle control
performanceElectric throttle control function does not oper-
ate properly.• Harness or connectors
(Throttle control motor circuit is open or
shorted)
• Electric throttle control actuator
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return
spring.
SEF058Y