Electric INFINITI QX56 2004 Factory Service Manual

EC-574Revision: August 2007
DTC P2135 TP SENSOR
2004 QX56
6. REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace the accelerator pedal assembly.
2. Perform EC-44, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-44, "
Throttle Valve Closed Position Learning" .
4. Perform EC-44, "
Idle Air Volume Learning" .
>>INSPECTION END
7. CHECK THROTTLE POSITION SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between electric throttle control actuator terminal 4 and ECM terminal 66.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK THROTTLE POSITION SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 50 and electric throttle control actuator terminal14, ECM
terminal 69 and electric throttle control actuator terminal 3.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
9. CHECK THROTTLE POSITION SENSOR
Refer to EC-575, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> GO TO 10.
10. REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR
1. Replace the electric throttle control actuator.
2. Perform EC-44, "
Throttle Valve Closed Position Learning" .
3. Perform EC-44, "
Idle Air Volume Learning" .
>>INSPECTION END
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END Continuity should exist.
Continuity should exist.

DTC P2135 TP SENSOR
EC-575
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Component InspectionUBS00HCQ
THROTTLE POSITION SENSOR
1. Reconnect all harness connectors disconnected.
2. Perform EC-44, "
Throttle Valve Closed Position Learning" .
3. Turn ignition switch ON.
4. Set selector lever to D position.
5. Check voltage between ECM terminals 50 (TP sensor 1signal),
69 (TP sensor 2signal) and ground under the following condi-
tions.
6. If NG, replace electric throttle control actuator and go to the next
step.
7. Perform EC-44, "
Throttle Valve Closed Position Learning" .
8. Perform EC-44, "
Idle Air Volume Learning" .
Removal and Installation UBS00HCR
ELECTRIC THROTTLE CONTROL ACTUATOR
Refer to EM-15, "INTAKE MANIFOLD" .
Terminal Accelerator pedal Voltage
50
(Throttle position sensor 1)Fully released More than 0.36V
Fully depressed Less than 4.75V
69
(Throttle position sensor 2)Fully released Less than 4.75V
Fully depressed More than 0.36V
PBIB1530E

EC-576Revision: August 2007
DTC P2138 APP SENSOR
2004 QX56
DTC P2138 APP SENSORPFP:18002
Component DescriptionUBS00HCS
The accelerator pedal position sensor is installed on the upper end
of the accelerator pedal assembly. The sensor detects the accelera-
tor position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors
are a kind of potentiometers which transform the accelerator pedal
position into output voltage, and emit the voltage signal to the ECM.
In addition, these sensors detect the opening and closing speed of
the accelerator pedal and feed the voltage signals to the ECM. The
ECM judges the current opening angle of the accelerator pedal from
these signals and controls the throttle control motor based on these
signals.
Idle position of the accelerator pedal is determined by the ECM
receiving the signal from the accelerator pedal position sensor. The ECM uses this signal for the engine oper-
ation such as fuel cut.
CONSULT-II Reference Value in Data Monitor ModeUBS00HCT
Specification data are reference values.
*: Accelerator pedal position sensor 2 signal is converted by ECM internally. Thus, it differ from ECM terminal voltage.
On Board Diagnosis LogicUBS00HCU
This self-diagnosis has the one trip detection logic.
NOTE:
If DTC P2138 is displayed with DTC P1229, first perform the trouble diagnosis for DTC P1229. Refer to
EC-424, "
DTC P1229 SENSOR POWER SUPPLY" .
FAIL -S AFE M OD E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
PBIB1741E
MONITOR ITEM CONDITION SPECIFICATION
ACCEL SEN1

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released 0.5 - 1.0V
Accelerator pedal: Fully depressed 4.2 - 4.8V
ACCEL SEN2*

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released 0.5 - 1.0V
Accelerator pedal: Fully depressed 4.2 - 4.8V
CLSD THL POS

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released ON
Accelerator pedal: Slightly depressed OFF
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2138
2138Accelerator pedal position
sensor circuit range/per-
formance problemRationally incorrect voltage is sent to ECM
compared with the signals from APP sensor 1
and APP sensor 2.

Harness or connector
(APP sensor 1 and 2 circuit is open or
shorted.)
(TP sensor circuit is shorted.)

Accelerator pedal position sensor 1 and 2

Electric throttle control actuator
(TP sensor)

ECM pin terminal
Engine operating condition in fail-safe mode
The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10
degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.

EC-580Revision: August 2007
DTC P2138 APP SENSOR
2004 QX56
2. CHECK APP SENSOR POWER SUPPLY CIRCUIT
1. Disconnect accelerator pedal position (APP) sensor harness
connector.
2. Turn ignition switch ON.
3. Check voltage between APP sensor terminals 6, 7 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 3.
3. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between APP sensor terminal 6 and ECM terminal 91.
Refer to Wiring Diagram.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit.
4. CHECK APP SENSOR 2 POWER SUPPLY CIRCUIT-II
Check the following.

Harness for short to power and short to ground, between the following terminals
OK or NG
OK >> GO TO 5.
NG >> Repair short to ground or short to power in harness connectors.
5. CHECK THROTTLE POSITION SENSOR
Refer to EC-575, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> GO TO 6.
BBIA0361E
Voltage: Approximately 5V
PBIB2083E
Continuity should exist.
ECM terminal Sensor terminal Reference Wiring Diagram
47 Electric throttle control actuator terminal 2EC-571
91 APP sensor terminal 6EC-578

DTC P2138 APP SENSOR
EC-581
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6. REPLACE ELECTRIC THROTTLE CONTROL ACTUATOR
1. Replace the electric throttle control actuator.
2. Perform EC-44, "
Throttle Valve Closed Position Learning" .
3. Perform EC-44, "
Idle Air Volume Learning" .
>>INSPECTION END
7. CHECK APP SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 82 and APP sensor terminal 1, ECM terminal 83 and
APP sensor terminal 3.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK APP SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 106 and APP sensor terminal 2, ECM terminal 98 and
APP sensor terminal 5.
Refer to Wiring Diagram.
2. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
9. CHECK ACCELERATOR PEDAL POSITION SENSOR
Refer to EC-561, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> GO TO 10.
10. REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace the accelerator pedal assembly.
2. Perform EC-44, "
Accelerator Pedal Released Position Learning" .
3. Perform EC-44, "
Throttle Valve Closed Position Learning" .
4. Perform EC-44, "
Idle Air Volume Learning" .
>>INSPECTION END
11 . CHECK INTERMITTENT INCIDENT
Refer to EC-127, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END Continuity should exist.
Continuity should exist.

EC-612Revision: August 2007
ELECTRICAL LOAD SIGNAL
2004 QX56
ELECTRICAL LOAD SIGNALPFP:25350
DescriptionUBS00HDL
The electrical load signal (Headlamp switch signal, rear window defogger switch signal, etc.) is transferred
through the CAN communication line from BCM to ECM via IPDM E/R.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDM
Specification data are reference values.
Diagnostic ProcedureUBS00HDN
1. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-I
1. Turn ignition switch ON.
2. Connect CONSULT-II and select “DATA MONITOR” mode.
3. Select “LOAD SIGNAL” and check indication under the following
conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2. CHECK LOAD SIGNAL CIRCUIT OVERALL FUNCTION-II
Check “LOAD SIGNAL” indication under the following conditions.
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
3. CHECK REAR WINDOW DEFOGGER SYSTEM
Refer to GW-78, "
REAR WINDOW DEFOGGER" .
>>INSPECTION END
4. CHECK HEADLAMP SYSTEM
Refer to LT- 6 , "
HEADLAMP (FOR USA)" , or LT-34, "HEADLAMP (FOR CANADA) - DAYTIME LIGHT SYS-
TEM -" .
>>INSPECTION END
MONITOR ITEM CONDITION SPECIFICATION
LOAD SIGNAL

Ignition switch: ONRear window defogger switch is ON
and/or lighting switch is in 2nd.ON
Rear window defogger switch is OFF
and lighting switch is OFF.OFF
Condition Indication
Rear window defogger switch ON ON
Rear window defogger switch OFF OFF
PBIB0103E
Condition Indication
Lighting switch ON at 2nd position ON
Lighting switch OFF OFF
PBIB0103E

AUTOMATIC SPEED CONTROL DEVICE (ASCD)
EC-647
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Revision: August 20072004 QX56
AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionUBS00HE7
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without pressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/h
(25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
SET OPERATION
Press ON/OFF(MAIN) switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press COAST/SET switch. (Then SET indicator in combination meter illuminates.)
ACCEL OPERATION
If the ACCEL/RESUME switch is pressed during cruise control driving, increase the vehicle speed until the
switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.

CANCEL switch is pressed

More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)

Brake pedal is depressed

Selector lever is changed to N, P, R position

Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed

VDC/TCS system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.

Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing COAST/SET switch or ACCEL/
RESUME switch.

Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If ON/OFF(MAIN) switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled
and vehicle speed memory will be erased.
COAST OPERATION
When the COAST/SET switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Park/Neutral position (PNP)
switchGear position
Combination meter* Vehicle speed
TCM* Powertrain revolution

EC-648Revision: August 2007
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
2004 QX56
RESUME OPERATION
When the ACCEL/RESUME switch is pressed after cancel operation other than pressing ON/OFF(MAIN)
switch is performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition
must meet following conditions.

Brake pedal is released

A/T selector lever is in other than P and N positions

Vehicle speed is greater than 40 km/h (25 MPH) and less than 144 km/h (89 MPH)
Component DescriptionUBS00HE8
ASCD STEERING SWITCH
Refer to EC-517 .
ASCD BRAKE SWITCH
Refer to EC-534 , and EC-621 .
STOP LAMP SWITCH
Refer to EC-534 , EC-551 and EC-621 .
ELECTRIC THROTTLE CONTROL ACTUATOR
Refer to EC-365 , EC-367 , EC-373 and EC-378 .
ASCD INDICATOR
Refer to EC-628 .

SERVICE DATA AND SPECIFICATIONS (SDS)
EC-649
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SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
Fuel PressureUBS00HE9
Idle Speed and Ignition TimingUBS00HEA
*1: Under the following conditions:

Air conditioner switch: OFF

Electric load: OFF (Lights and heater fan)

Steering wheel: Kept in straight-ahead position
Calculated Load ValueUBS00HEB
Mass Air Flow SensorUBS00HEC
*: Engine is warmed up to normal operating temperature and running under no-load.
Intake Air Temperature SensorUBS00HED
Engine Coolant Temperature SensorUBS00HEE
A/F Sensor 1 HeaterUBS00HEF
Heated Oxygen sensor 2 HeaterUBS00HEG
Crankshaft Position Sensor (POS)UBS00HEH
Refer to EC-260, "Component Inspection" .
Camshaft Position Sensor (PHASE)UBS00HEI
Refer to EC-266, "Component Inspection" .
Throttle Control MotorUBS00HEJ
Fuel pressure at idling kPa (kg/cm2 , psi)Approximately 350 (3.57, 51)
Target idle speed
No-load*1 (in P or N position)650±50 rpm
Air conditioner: ON In P or N position 700 rpm or more
Ignition timing In P or N position 15° ± 5° BTDC
Condition Calculated load value % (Using CONSULT-II or GST)
At idle14.0 - 33.0
At 2,500 rpm12.0 - 25.0
Supply voltage Battery voltage (11 - 14V)
Output voltage at idle1.1 - 1.4V*
Mass air flow (Using CONSULT-II or GST)3.0 - 9.0 g·m/sec at idle*
9.0 - 28.0 g·m/sec at 2,500 rpm*
Temperature °C (°F) Resistance kΩ
25 (77)1.9 - 2.1
80 (176)0.31 - 0.37
Temperature °C (°F) Resistance kΩ
20 (68)2.1 - 2.9
50 (122)0.68 - 1.00
90 (194)0.236 - 0.260
Resistance [at 25°C (77°F)] 3.3 - 4.3Ω
Resistance [at 25°C (77°F)] 5.0 - 7.0Ω
Resistance [at 25°C (77°F)] Approximately 1 - 15Ω

PRECAUTIONS
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Revision: August 20072004 QX56
PRECAUTIONSPFP:00001
Service NoticeEIS002X1

When removing or installing various parts, place a cloth or padding on the vehicle body to prevent
scratches.

Handle trim, molding, instruments, grille, etc. carefully during removing or installing. Be careful not to soil
or damage them.

Apply sealing compound where necessary when installing parts.

When applying sealing compound, be careful that the sealing compound does not protrude from parts.

When replacing any metal parts (for example body outer panel, members, etc.), be sure to take rust pre-
vention measures.
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EIS002X2
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WA RN ING:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.