2005 INFINITI QX4 engine

DTC P0507 ISC SYSTEM
EC-377
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Revision: October 20052005 QX56
Diagnostic ProcedureUBS00H6O
1. CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2. CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Discover air leak location and repair.
3. REPLACE ECM
1. Stop engine.
2. Replace ECM.
3. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to
BL-139, "
ECM Re-communicating Function" .
4. Perform EC-90, "
VIN Registration" .
5. Perform EC-90, "
Accelerator Pedal Released Position Learning" .
6. Perform EC-90, "
Throttle Valve Closed Position Learning" .
7. Perform EC-91, "
Idle Air Volume Learning" .
>>INSPECTION END

EC-378Revision: October 2005
DTC P0550 PSP SENSOR
2005 QX56
DTC P0550 PSP SENSORPFP:49763
Component DescriptionUBS00H6P
Power steering pressure (PSP) sensor is installed to the power
steering high-pressure tube and detects a power steering load. This
sensor is a potentiometer which transforms the power steering load
into output voltage, and emits the voltage signal to the ECM. The
ECM controls the electric throttle control actuator and adjusts the
throttle valve opening angle to increase the engine speed and
adjusts the idle speed for the increased load.
CONSULT-II Reference Value in Data Monitor ModeUBS00H6Q
Specification data are reference values.
On Board Diagnosis LogicUBS00H6R
The MIL will not light up for this diagnosis.
NOTE:
If DTC P0550 is displayed with DTC P1229, first perform the trouble diagnosis for DTC P1229. Refer to
EC-454, "
DTC P1229 SENSOR POWER SUPPLY" .
DTC Confirmation ProcedureUBS00H6S
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 and let it idle for at least 5 seconds.
4. If 1st trip DTC is detected, go to EC-380, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
BBIA0365E
MONITOR ITEM CONDITION SPECIFICATION
PW/ST SIGNAL

Engine: After warming up, idle
the engineSteering wheel: Not being turned
(Forward direction)OFF
Steering wheel: Being turned ON
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0550
0550Power steering pressure
sensor circuitAn excessively low or high voltage from the
sensor is sent to ECM.

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

Power steering pressure sensor
SEF 0 58 Y

EC-380Revision: October 2005
DTC P0550 PSP SENSOR
2005 QX56
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 ProcedureUBS00H6U
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-162, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
12 RPower steering pressure
sensor[Engine is running]

Steering wheel: Being turned.0.5 - 4.5V
[Engine is running]

Steering wheel: Not being turned.0.4 - 0.8V
67 B Sensor ground[Engine is running]

Warm-up condition

Idle speedApproximately 0V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
BBIA0354E

EC-382Revision: October 2005
DTC P0550 PSP SENSOR
2005 QX56
6. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionUBS00H6V
POWER STEERING PRESSURE SENSOR
1. Reconnect all harness connectors disconnected.
2. Start engine and let it idle.
3. Check voltage between ECM terminal 12 and ground under the
following conditions.
Removal and Installation UBS00H6W
POWER STEERING PRESSURE SENSOR
Refer to PS-31, "HYDRAULIC LINE" .
Condition Voltage
Steering wheel: Being turned. 0.5 - 4.5V
Steering wheel: Not being turned. 0.4 - 0.8V
MBIB0126E

DTC P0605 ECM
EC-383
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Revision: October 20052005 QX56
DTC P0605 ECMPFP:23710
Component DescriptionUBS00H6X
The ECM consists of a microcomputer and connectors for signal
input and output and for power supply. The ECM controls the engine.
On Board Diagnosis LogicUBS00H6Y
This self-diagnosis has one or two trip detection logic.
FAIL-SAFE MODE
ECM enters fail-safe mode when the malfunction A is detected.
DTC Confirmation ProcedureUBS00H6Z
Perform PROCEDURE FOR MALFUNCTION A first. If the 1st trip DTC cannot be confirmed, perform
PROCEDURE FOR MALFUNCTION B. If there is no malfunction on PROCEDURE FOR MALFUNCTION
B, perform PROCEDURE FOR MALFUNCTION C.
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 A
With CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. If 1st trip DTC is detected, go to EC-384, "
Diagnostic Procedure"
With GST
Follow the procedure “With CONSULT-II” above.
PBIB11 64 E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0605
0605Engine control moduleA) ECM calculation function is malfunctioning.

ECM B) ECM EEP-ROM system is malfunctioning.
C) ECM self shut-off function is malfunctioning.
Detected items Engine operation condition in fail-safe mode
Malfunction A

ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx.
5 degrees) by the return spring.

ECM deactivates ASCD operation.
SEF 0 58 Y

EC-386Revision: October 2005
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2005 QX56
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATERPFP:22693
DescriptionUBS00H71
SYSTEM DESCRIPTION
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F sensor 1 element at the specified range.
CONSULT-II Reference Value in Data Monitor ModeUBS00H72
Specification data are reference values.
On Board Diagnosis LogicUBS00H73
DTC Confirmation ProcedureUBS00H74
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 between 10.5V and 16V at
idle.
WITH CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and let it idle for at least 10 seconds.
3. If 1st trip DTC is detected, go to EC-390, "
Diagnostic Procedure"
.
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Sensor Input Signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)Engine speed
Air fuel ratio (A/F) sensor 1
heater controlAir fuel ratio (A/F) sensor 1
heater
Mass air flow sensor Amount of intake air
MONITOR ITEM CONDITION SPECIFICATION
A/F S1 HTR (B1)
A/F S1 HTR (B2)

Engine: After warming up, idle the engine 0 - 100%
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1031
1031
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
lowThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively low voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
open or shorted.)

A/F sensor 1 heater P1051
1051
(Bank 2)
P1032
1032
(Bank 1)Air fuel ratio (A/F) sensor
1 heater control circuit
highThe current amperage in the heated air fuel ratio
(A/F) sensor 1 heater circuit is out of the normal
range.
(An excessively high voltage signal is sent to ECM
through the heated air fuel ratio (A/F) sensor 1
heater.)

Harness or connectors
(The A/F sensor 1 heater circuit is
shorted.)

A/F sensor 1 heater P1052
1052
(Bank 2)
SEF 0 58 Y

EC-388Revision: October 2005
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2005 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
2O/BA/F sensor 1 heater
(bank 1)[Engine is running]

Warm-up condition

Idle speedApproximately 5V
PBIB1584E

EC-390Revision: October 2005
DTC P1031, P1032, P1051, P1052 A/F SENSOR 1 HEATER
2005 QX56
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnostic ProcedureUBS00H76
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-162, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
24 BR/WA/F sensor 1 heater
(bank 2)[Engine is running]

Warm-up condition

Idle speedApproximately 5V
PBIB1584E
BBIA0354E