Nissan Xterra. Manual - part 335

EC-466

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

FUEL INJECTOR

Resistance: 11.1 - 14.5

Ω [at 10 - 60°C (50 - 140°F)]

FUEL PUMP

EC-467

< DTC/CIRCUIT DIAGNOSIS >

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FUEL PUMP

Description

INFOID:0000000009484222

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

start ability. 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.

Diagnosis Procedure

INFOID:0000000009484223

1.

CHECK OVERALL FUNCTION

1. Turn ignition switch ON.

2. Pinch fuel feed hose with two fingers.

Fuel pressure pulsation should be felt on the fuel feed hose

for 1 second after ignition switch is turned ON.

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.

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 cranking

Operates.

When engine is stopped

Stops in 1.5 seconds.

Except as shown above

Stops.

PBIB1569E

BBIA0563E

EC-468

< DTC/CIRCUIT DIAGNOSIS >

[VQ40DE]

FUEL PUMP

4. Check voltage between ECM terminal 43 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 3.

3.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-II

Check voltage between IPDM E/R terminal 46 and ground with CONSULT or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 12.

4.

DETECT MALFUNCTIONING PART

Check harness for open or short between IPDM E/R and ECM

Harness connectors E5, F14

>> Repair harness or connectors.

5.

CHECK FUEL PUMP POWER SUPPLY CIRCUIT-III

1. Turn ignition switch OFF.

2. Reconnect all harness connectors disconnected.

3. Disconnect “fuel level sensor unit and fuel pump” harness con-

nector.

4. Turn ignition switch ON.

5. Check voltage between “fuel level sensor unit and fuel pump”

terminal 1 and ground with CONSULT or tester. 

6. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 9.

NG

>> GO TO 6.

6.

CHECK 15A FUSE

1. Turn ignition switch OFF.

2. Disconnect 15A fuse.

3. Check 15 A fuse (No.48).
OK or NG

OK

>> GO TO 7.

NG

>> Replace 15A fuse.

7.

CHECK FUEL PUMP POWER SUPPLY CURCUIT-IV

1. Disconnect IPDM E/R harness connector E119.

2. Check harness continuity between “fuel level sensor unit and fuel pump” terminal 1 and IPDM E/R termi-

nal 13.

Refer to Wiring Diagram. 

3. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 12.

NG

>> GO TO 8.

Voltage: Battery voltage 

Voltage: Battery voltage

Voltage:

Battery voltage should exist for 1 sec-
ond after ignition switch is turned ON.

BBIA0545E

Continuity should exist.

FUEL PUMP

EC-469

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8.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors C1, E41

• Harness for open or short between “fuel level sensor unit and fuel pump” and IPDM E/R

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

9.

CHECK FUEL PUMP GROUND CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between “fuel level sensor unit and fuel pump” terminal 3 and ground.

Refer to Wiring Diagram.

2. Also check harness for short to ground.
OK or NG

OK

>> GO TO 11.

NG

>> GO TO 10.

10.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors C1, E41

• Harness for open or short between “fuel level sensor unit and fuel pump” and ground

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

11.

CHECK FUEL PUMP

Refer to 

EC-469, "Component Inspection"

.

OK or NG

OK

>> GO TO 12.

NG

>> Replace fuel pump. Refer to 

FL-11, "Removal and Installation"

.

12.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

OK or NG

OK

>> Replace IPDM E/R. Refer to 

PCS-27, "Removal and Installation"

.

NG

>> Repair or replace harness or connectors.

Component Inspection

INFOID:0000000009484224

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.

Continuity should exist.

Resistance: Approximately 0.2 - 5.0

Ω [at 25°C (77°F)]