2011 INFINITI QX56 engine

P1574 ASCD VEHICLE SPEED SENSOREC-447
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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P1574 ASCD VEHICLE SPEED SENSOR
DescriptionINFOID:0000000006288349
The ECM receives two vehicle speed signals by the CAN
communication line. One is sent from “combination
meter”, and the other is from TCM (Transmission cont rol module). The ECM uses these signals for ASCD con-
trol. Refer to EC-48, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD) : System Description" for ASCD func-
tions.
DTC LogicINFOID:0000000006288350
DTC DETECTION LOGIC
NOTE:
 If DTC P1574 is displayed with DTC UXXXX, perform the trouble diagnosis for DTC UXXXX.
 If DTC P1574 is displayed with DTC P0500, perform the trouble diagnosis for DTC P0500. Refer to
EC-356, "
DTC Logic".
 If DTC P1574 is displayed with DTC P0605, perform the trouble diagnosis for DTC P0605. Refer to
EC-376, "
DTC Logic".
 If DTC P1574 is displayed with DTC P0607, perform the trouble diagnosis for DTC P0607. Refer to
EC-378, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine (VDC switch OFF).
2. Drive the vehicle at more than 40 km/h (25 MPH). CAUTION:
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheel s 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.
3. Check DTC.
Is DTC detected?
YES >> Proceed to EC-449, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288351
1.CHECK DTC WITH TCM
Check DTC with TCM. Refer to TM-61, "
CONSULT-III Function (TRANSMISSION)".
Is the inspection result normal?
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1574 ASCD VHL SPD SEN
(ASCD vehicle speed sensor) ECM 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 elec tric unit (control
unit)
 Wheel sensor
TCM
ECM
Revision: 2010 May2011 QX56

P1574 ICC VEHICLE SPEED SENSOR
EC-449
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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EC
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P1574 ICC VEHICLE SPEED SENSOR
DescriptionINFOID:0000000006288352
The ECM receives two vehicle speed signals by the CAN
communication line. One is sent from “combination
meter”, and the other is from TCM (Transmission cont rol module). The ECM uses these signals for ICC con-
trol. Refer to CCS-12, "
System Description" for ICC functions.
DTC LogicINFOID:0000000006288353
DTC DETECTION LOGIC
NOTE:
If DTC P1574 is displayed with DTC UXXXX, first perform the tr ouble diagnosis for DTC UXXXX.
 If DTC P1574 is displayed with DT C P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-356, "
DTC Logic".
 If DTC P1574 is displayed with DT C P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-376, "
DTC Logic".
 If DTC P1574 is displayed with DT C P0607, first perform the trouble diagnosis for DTC P0607. Refer
to EC-378, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine (VDC switch OFF).
2. Drive the vehicle at more than 40 km/h (25 MPH). CAUTION:
Always drive vehicle at a safe speed.
NOTE:
This procedure may be conducted with the drive wheel s 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.
3. Check DTC.
Is DTC detected?
YES >> Proceed to EC-449, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006288354
1.CHECK DTC WITH TCM
Check DTC with TCM. Refer to TM-61, "
CONSULT-III Function (TRANSMISSION)".
Is the inspection result normal?
YES >> GO TO 2.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1574 ASCD VHL SPD SEN
(ICC vehicle speed sensor) ECM 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
Revision: 2010 May2011 QX56

EC-452
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P1607 VVEL CONTROL MODULE
P1607 VVEL CONTROL MODULE
DTC LogicINFOID:0000000006217953
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 10 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for at least 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-452, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217954
1.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON.
2. Erase DTC.
3. Perform DTC Confirmation Procedure. See EC-452, "
DTC Logic".
Is the DTC P1607 displayed again?
YES >> Replace VVEL control module. Refer to EC-536, "Removal and Installation".
NO >> INSPECTION END
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P1607 VVEL CONTROL MODULE
(VVEL control module circuit)  The internal circui
t of the VVEL control
module is malfunctioning.  VVEL control module
Revision: 2010 May2011 QX56

EC-458
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2100, P2103 THROTTLE
CONTROL MOTOR RELAY
P2100, P2103 THROTTLE CONTROL MOTOR RELAY
DTC LogicINFOID:0000000006217960
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
Which DTC is detected?
P2100 >> GO TO 2.
P2103 >> GO TO 3.
2.PERFORM DTC CONFIRMATION PROCEDURE FOR DTC P2100
1. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
Is DTC detected?
YES >> Go to EC-458, "Diagnosis Procedure".
NO >> INSPECTION END
3.PERFORM DTC CONFIRMATION PROCEDURE FOR DTC P2103
1. Turn ignition switch ON and wait at least 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-458, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217961
1.CHECK THROTTLE CONTROL MOTO R RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect IPDM E/R harness connector E15.
4. Check the continuity between IPDM E/ R harness connector and ECM harness connector.
5. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 3.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2100 ETC MOT PWR-B1
[Throttle contro
l motor relay
circuit open (bank 1)] ECM detects that the voltage of power
source for throttle
control motor is ex-
cessively low.  Harness or connectors
(Throttle control motor relay circuit is open)
 Throttle control motor relay
P2103 ETC MOT PWR
(Throttle contro
l motor relay
circuit short) ECM detects that the throttle control
motor relay is stuck ON.  Harness or connectors
(Throttle control motor re lay circuit is shorted)
 Throttle control motor relay
IPDM E/R ECM Continuity
Connector Terminal Connector Terminal
E15 60 E80 123 Existed
Revision: 2010 May2011 QX56

EC-460
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2101 ELECTRIC THROTTLE CONTROL FUNCTION
P2101 ELECTRIC THROTTL
E CONTROL FUNCTION
DescriptionINFOID:0000000006217962
Electric throttle control actuator consists of th rottle 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. ECM controls the throttle valve openi ng angle in response to driving condition via the throttle
control motor.
DTC LogicINFOID:0000000006217963
DTC DETECTION LOGIC
NOTE:
 If DTC P2101 is displayed with DTC P2100, first pe rform the trouble diagnosis for DTC P2100. Refer
to EC-458, "
DTC Logic".
 If DTC P2101 is displayed with DTC P2119, first pe rform the trouble diagnosis for DTC P2119. Refer
to EC-466, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is 11 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
Is DTC detected?
YES >> Go to EC-460, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217964
1.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
1. Check the voltage between ECM harness connector and ground under the following conditions.
Is the inspection result normal?
YES >> GO TO 8.
NO >> GO TO 2.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2101 Electric throttle control
performance Electric throttle control function does not
operate properly.  Harness or connectors
(Throttle control motor circuit is open or shorted)
 Electric throttle control actuator
ECM Ground Condition Voltage
Connector Terminal
E80 173 Ground Ignition switch:
OFF
Approx. 0 V
Ignition switch:
ON Battery voltage
Revision: 2010 May2011 QX56

EC-464
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2118 THROTTLE CONTROL MOTOR
P2118 THROTTLE CONTROL MOTOR
DTC LogicINFOID:0000000006217967
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
Is DTC detected?
YES >> Go to EC-464, "DTC Logic".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217968
1.CHECK THROTTLE CONTROL MOTOR OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect electric throttle control actuator harness connector.
2. Disconnect ECM harness connector.
3. Check the continuity between electric throttle control actuator harness connector and ECM harness con-
nector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace malfunctioning part.
2.CHECK THROTTLE CONTROL MOTOR
Refer to EC-465, "
Component Inspection (Electric Throttle Control Motor)".
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 4.
3.CHECK INTERMITTENT INCIDENT
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2118 ETC MOT-B1
(Throttle control motor circuit
short) ECM detects short in both circuits between
ECM and throttle control motor.  Harness or connectors
(Throttle control motor circuit is shorted.)
 Electric throttle control actuator
(Throttle control motor)
Electric throttle control actuator ECM Continuity
Connector Terminal Connector Terminal
F66 5
F110 57 Not existed
63 Existed
6 57 Existed
63 Not existed
Revision: 2010 May2011 QX56

EC-466
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2119 ELECTRIC THROTTLE CONTROL ACTUATOR
P2119 ELECTRIC THROTTLE CONTROL ACTUATOR
DTC LogicINFOID:0000000006217970
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROC EDURE FOR MALFUNCTION A AND B
1. Turn ignition switch ON and wait at least 1 second.
2. Selector lever position is D and wait at least 3 seconds.
3. Selector lever position is P.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Turn ignition switch ON and wait at least 1 second.
6. Selector lever position is D and wait at least 3 seconds.
7. Selector lever position is P.
8. Turn ignition switch OFF, wait at least 10 seconds, and then turn ON.
9. Check DTC.
Is DTC detected?
YES >> Go to EC-466, "Diagnosis Procedure".
NO >> GO TO 3.
3.PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION C
1. Turn ignition switch ON and wait at least 1 second.
2. Selector lever position is D and wait at least 3 seconds.
3. Selector lever position is N or P.
4. Start engine and let it idle for 3 seconds.
5. Check DTC.
Is DTC detected?
YES >> Go to EC-466, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217971
1.CHECK ELECTRIC THROTTLE CONTROL ACTUATOR VISUALLY
1. Turn ignition switch OFF.
2. Remove the intake air duct.
3. Check if foreign matter is caught between the throttle valve and the housing.
Is the inspection result normal?
YES >> GO TO 2.
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2119 ETC ACTR-B1
(Electric throttle control actuator) A)
Electric throttle control actuator does not
function properly due to the return spring
malfunction.
 Electric throttle control actuator
B) Throttle valve opening angle in fail-safe
mode is not in specified range.
C) ECM detects that the throttle valve is stuck
open.
Revision: 2010 May2011 QX56

EC-468
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P2122, P2123 APP SENSOR
P2122, P2123 APP SENSOR
DTC LogicINFOID:0000000006217972
DTC DETECTION LOGIC
NOTE:
If DTC P2122 or P2123 is displayed with DTC P
0643, perform the trouble diagnosis for DTC P0643.
Refer to EC-381, "
DTC Logic".
DTC CONFIRMATION PROCEDURE
1.PRECONDITIONING
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confi rm that battery voltage is 8 V or more at idle.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE
1. Start engine and let it idle for 1 second.
2. Check DTC.
Is DTC detected?
YES >> Go to EC-468, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000006217973
1.CHECK ACCELERATOR PEDAL POSITION SENSOR 1 POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between APP sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between ECM and APP sensor
 Loose or poor connection for each connector and harness
DTC No. Trouble diagnosis name
(Trouble diagnosis content) DTC detecting condition Possible cause
P2122 APP SEN 1/CIRC
(Accelerator pedal position
sensor 1 circuit low input) An excessively low voltage from the APP
sensor 1 is sent to ECM.
 Harness or connectors
(APP sensor 1 circuit is open or shorted.)
 Accelerator pedal position sensor (APP sensor 1)
P2123 APP SEN 1/CIRC
(Accelerator pedal position
sensor 1 circuit high input) An excessively high voltage from the APP
sensor 1 is sent to ECM.
APP sensor
Ground Voltage (V)
Connector Terminal
E110
(Without ICC) 2
Ground Approx. 5
E67
(With ICC) 12
Revision: 2010 May2011 QX56