Infiniti FX35, FX50 (S51). Manual - part 733

FUEL PUMP

EC-473

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

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FUEL PUMP

Description

INFOID:0000000005237088

*: 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, it knows that the
engine is rotating, and causes the pump to operate. If the engine speed signal is not received when the igni-
tion 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 Function Check

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1.

CHECK FUEL PUMP FUNCTION

1.

Turn ignition switch ON.

2.

Pinch fuel feed hose (1) with two fingers.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>>

EC-473, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005237090

1.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-I

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Turn ignition switch ON.

4.

Check the voltage between ECM harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 2.

2.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II

Sensor

Input signal to ECM

ECM Function

Actuator

Crankshaft position sensor
Camshaft position sensor

Engine speed*

Fuel pump control

Fuel pump relay

↓

Fuel pump

Battery

Battery voltage*

Condition

Fuel pump operation

Ignition switch is turned to ON.

Operates for 1 second.

Engine running and cranking

Operates.

When engine is stopped

Stops in 1.5 seconds.

Except as shown above

Stops.

Fuel pressure pulsation should be felt on the fuel feed 
hose for 1 second after ignition switch is turned ON.

JMBIA0020ZZ

ECM

Ground

Voltage

Connector

Terminal

F101

22

Ground

Battery voltage

EC-474

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

FUEL PUMP

Check the voltage between IPDM E/R harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 10.

3.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors E3, F1
• Harness connectors F104, F105
• Harness for open or short between IPDM E/R and ECM

>> Repair open circuit, short to ground or short to power in harness or connectors.

4.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II

1.

Turn ignition switch OFF.

2.

Reconnect all harness connectors disconnected.

3.

Disconnect “fuel level sensor unit and fuel pump (main)” harness connector.

4.

Turn ignition switch ON.

5.

Check the voltage between “fuel level sensor unit and fuel pump (main)” harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 8.

NO

>> GO TO 5.

5.

CHECK 15 A FUSE

1.

Turn ignition switch OFF.

2.

Disconnect 15 A fuse (No. 41) from IPDM E/R.

3.

Check 15 A fuse.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace 15 A fuse.

6.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-IV

1.

Disconnect IPDM E/R harness connector E5.

2.

Check the continuity between IPDM E/R harness connector and “fuel level sensor unit and fuel pump
(main)” harness connector.

3.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 10.

NO

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

IPDM E/R

Ground

Voltage

Connector

Terminal

E7

77

Ground

Battery voltage

Fuel level sensor unit and fuel pump (main)

Ground

Voltage

Connector

Terminal

B22

1

Ground

Battery voltage should exist for 1 second 
after ignition switch is turned ON.

IPDM E/R

Fuel level sensor unit and fuel pump 

(main)

Continuity

Connector

Terminal

Connector

Terminal

E5

13

B22

1

Existed

FUEL PUMP

EC-475

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

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Check the following.
• Harness connectors E121, B3
• IPDM E/R harness connector E5
• Harness for open or short between IPDM E/R and “fuel level sensor unit and fuel pump (main)”

>> Repair open circuit or short to power in harness or connectors.

8.

CHECK FUEL PUMP GROUND CIRCUIT

1.

Turn ignition switch OFF.

2.

Check the continuity between “fuel level sensor unit and fuel pump (main)” harness connector and
ground.

3.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 9.

NO

>> Repair open circuit or short to power in harness or connectors.

9.

CHECK FUEL PUMP

Refer to 

EC-475, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 10.

NO

>> Replace fuel pump.

10.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-36, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace IPDM E/R.

NO

>> Repair or replace harness or connectors.

Component Inspection

INFOID:0000000005237091

1.

CHECK FUEL PUMP

1.

Turn ignition switch OFF.

2.

Disconnect “fuel level sensor unit and fuel pump (main)” harness connector.

3.

Check resistance between “fuel level sensor unit and fuel pump” terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace “fuel level sensor unit and fuel pump”

Fuel level sensor unit and fuel pump 

(main)

Ground

Continuity

Connector

Terminal

B22

3

Ground

Existed

Terminals

Resistance

1 and 3

0.2 - 5.0 

Ω

 [at 25

°

C (77

°

F)]

EC-476

< DTC/CIRCUIT DIAGNOSIS >

[VQ35HR]

ICC BRAKE SWITCH

ICC BRAKE SWITCH

Description

INFOID:0000000005237092

When the brake pedal is depressed, ICC brake switch is turned OFF and stop lamp switch is turned ON. ECM
detects the state of the brake pedal by those two types of input (ON/OFF signal).
Refer to 

CCS-24, "System Description"

 for the ICC function.

Component Function Check

INFOID:0000000005237093

1.

CHECK ICC BRAKE SWITCH FUNCTION

 With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-III.

3.

Check “BRAKE SW1” indication under the following conditions.

 Without CONSULT-III

1.

Turn ignition switch ON.

2.

Check the voltage between ECM harness connector terminals as follows.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-476, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005237094

1.

CHECK DTC WITH ICC SENSOR INTEGRATED UNIT

Refer to 

CCS-44, "Diagnosis Description"

.

Are any DTCs detected?

YES

>> Perform the Diagnosis Procedure corresponding to the detected DTC.

NO

>> GO TO 2.

2.

CHECK OVERALL FUNCTION

 With CONSULT-III

1.

Turn ignition switch ON.

2.

Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-III.

3.

Check “BRAKE SW1” indication under the following conditions.

 Without CONSULT-III

1.

Turn ignition switch ON.

2.

Check the voltage between ECM harness connector terminals under the following conditions.

Monitor item

Condition

Indication

BRAKE SW1
(ICC brake switch)

Brake pedal

Slightly depressed

OFF

Fully released

ON

ECM

Condition

Voltage (V)

Connector

+

–

Terminal

Terminal

M107

126

(ICC brake switch signal)

128

Brake pedal

Slightly depressed

Approx. 0

Fully released

Battery voltage

Monitor item

Condition

Indication

BRAKE SW1
(ICC brake switch)

Brake pedal

Slightly depressed

OFF

Fully released

ON