2005 INFINITI QX4 fuel

FUEL PUMP CIRCUIT
EC-637
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
FUEL PUMP CIRCUITPFP:17042
DescriptionUBS00HDB
SYSTEM DESCRIPTION
*: ECM determines the start signal status by the signals of engine speed and battery voltage.
The ECM activates the fuel pump for several seconds after the ignition switch is turned ON to improve engine
startability. If the ECM receives a engine speed signal from the camshaft position sensor (PHASE), it knows
that the engine is rotating, and causes the pump to operate. If the engine speed signal is not received when
the ignition switch is ON, the engine stalls. The ECM stops pump operation and prevents battery discharging,
thereby improving safety. The ECM does not directly drive the fuel pump. It controls the ON/OFF fuel pump
relay, which in turn controls the fuel pump.
COMPONENT DESCRIPTION
A turbine type design fuel pump is used in the fuel tank.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDC
Specification data are reference values.
Sensor Input signal to ECM ECM Function Actuator
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)Engine speed*
Fuel pump control Fuel pump relay
Battery Battery voltage*
Condition Fuel pump operation
Ignition switch is turned to ON. Operates for 1 second.
Engine running and crankingOperates.
When engine is stoppedStops in 1.5 seconds.
Except as shown aboveSto ps.
BBIA0402E
MONITOR ITEM CONDITION SPECIFICATION
FUEL PUMP RLY

For 1 second after turning ignition switch ON

Engine running or crankingON

Except above conditions OFF

EC-638Revision: October 2005
FUEL PUMP CIRCUIT
2005 QX56
Wiring DiagramUBS00HDD
BBWA1714E

FUEL PUMP CIRCUIT
EC-639
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 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 ProcedureUBS00HDE
1. CHECK OVERALL FUNCTION
1. Turn ignition switch ON.
2. Pinch fuel feed hose with two fingers.
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
2. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Turn ignition switch ON.
4. Check voltage between ECM terminal 113 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
113 GR Fuel pump relay[Ignition switch: ON]

For 1 second after turning ignition switch ON
[Engine is running]0 - 1.5V
[Ignition switch: ON]

More than 1 second after turning ignition
switch ON.BATTERY VOLTAGE
(11 - 14V)
Fuel pressure pulsation should be felt on the fuel feed
hose for 1 second after ignition switch is turned ON.
BBIA0357E
Voltage: Battery voltage
PBIB11 87 E

EC-640Revision: October 2005
FUEL PUMP CIRCUIT
2005 QX56
3. CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector E122.
3. Turn ignition switch ON.
4. Check voltage between IPDM E/R terminal 46 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 13.
4. DETECT MALFUNCTIONING PART
Check harness for open or short between IPDM E/R and ECM.
>> Repair harness or connectors.
5. CHECK CONDENSER POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Reconnect all harness connectors disconnected.
3. Disconnect condenser harness connector.
4. Turn ignition switch ON.
5. Check voltage between condenser terminal 1 and ground with
CONSULT-II or tester.
6. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 8.
NG >> GO TO 6.Voltage: Battery voltage
PBIB2084E
BBIA0388E
Voltage: Battery voltage should exist for 1 sec-
ond after ignition switch is turned ON.
PBIB0624E

FUEL PUMP CIRCUIT
EC-641
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
6. CHECK 15A FUSE
1. Turn ignition switch OFF.
2. Disconnect 15A fuse.
3. Check 15A fuse.
OK or NG
OK >> GO TO 7.
NG >> Replace fuse.
7. CHECK CONDENSER POWER SUPPLY CIRCUIT-II FOR OPEN AND SHORT
1. Disconnect IPDM E/R harness connector E119.
2. Check harness continuity between IPDM E/R terminal 13 and condenser terminal 1.
Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 13.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
8. CHECK CONDENSER GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between condenser terminal 2 and ground.
Refer to Wiring Diagram.
2. Also check harness for short to power.
OK or NG
OK >> GO TO 9.
NG >> Repair open circuit or short to power in harness or connectors.
9. CHECK CONDENSER
Refer to EC-642, "
Component Inspection" .
OK or NG
OK >> GO TO 10.
NG >> Replace condenser.
10. CHECK FUEL PUMP POWER SUPPLY AND GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect “fuel level sensor unit and fuel pump” harness con-
nector.
3. Disconnect IPDM E/R harness connector E119.
4. Check harness continuity between IPDM E/R terminal 13 and
“fuel level sensor unit and fuel pump” terminal 1, “fuel level sen-
sor unit and fuel pump” terminal 3 and ground.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 12.
NG >> GO TO 11.Continuity should exist.
Continuity should exist.
Continuity should exist.
BBIA0583E

EC-642Revision: October 2005
FUEL PUMP CIRCUIT
2005 QX56
11 . DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E41, C1

Harness for open or short between fuel pump and IPDM E/R

Harness for open or short between fuel pump and ground
>> Repair open circuit or short to ground or short to power in harness or connectors.
12. CHECK FUEL PUMP
Refer to EC-642, "
Component Inspection" .
OK or NG
OK >> GO TO 13.
NG >> Replace “fuel level sensor unit and fuel pump”.
13. CHECK INTERMITTENT INCIDENT
Refer to EC-156, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> Replace IPDM E/R.
NG >> Repair or replace harness or connectors.
Component InspectionUBS00HDF
FUEL PUMP
1. Disconnect “fuel level sensor unit and fuel pump” harness connector.
2. Check resistance between fuel level sensor unit and fuel pump
terminals 1 and 3.
CONDENSER
1. Turn ignition switch OFF.
2. Disconnect condenser harness connector.
3. Check resistance between condenser terminals as 1 and 2.
Removal and InstallationUBS00HDG
FUEL PUMP
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" . Resistance: 0.2 - 5.0Ω [at 25°C (77°F)]
SEC9 18 C
Resistance Above 1 MΩ at 25°C (77°F)
PBIB0794E

SERVICE DATA AND SPECIFICATIONS (SDS)
EC-669
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
SERVICE DATA AND SPECIFICATIONS (SDS)PFP:00030
Fuel PressureUBS00HE9
Idle Speed and Ignition TimingUBS00HEA
*: 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-290, "Component Inspection" .
Camshaft Position Sensor (PHASE)UBS00HEI
Refer to EC-297, "Component Inspection" .
Throttle Control MotorUBS00HEJ
Fuel pressure at idling kPa (kg/cm2 , psi)Approximately 350 (3.57, 51)
Target idle speed
No-load* (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 idle1.0 - 1.3V*
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)1.94 - 2.06
80 (176)0.295 - 0.349
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)] 2.3 - 4.3Ω
Resistance [at 25°C (77°F)] 5.0 - 7.0Ω
Resistance [at 25°C (77°F)] Approximately 1 - 15Ω

EC-670Revision: October 2005
SERVICE DATA AND SPECIFICATIONS (SDS)
2005 QX56
InjectorUBS00HEK
Fuel PumpUBS00HEL
Resistance [at 10 - 60°C (50 - 140°F)] 11.1 - 14.5Ω
Resistance [at 25°C (77°F)] 0.2 - 5.0Ω