Infiniti QX4 (R50). Manual — part 289
Diagnostic Procedure
NBEC0391
1
INSPECTION START
Do you have CONSULT-II?
Yes or No
Yes
©
GO TO 2.
No
©
GO TO 3.
2
CHECK OVERALL FUNCTION
With CONSULT-II
1. Turn ignition switch “ON”.
2. Check “START SIGNAL” in “DATA MONITOR” mode with CONSULT-II under the following conditions.
SEF072Y
OK or NG
OK
©
INSPECTION END
NG
©
GO TO 4.
3
CHECK OVERALL FUNCTION
Without CONSULT-II
Check voltage between ECM terminal 42 and ground under the following conditions.
SEF362X
OK or NG
OK
©
INSPECTION END
NG
©
GO TO 4.
4
CHECK STARTING SYSTEM
Turn ignition switch “OFF”, then turn it to “START”.
Does starter motor operate?
Yes or No
Yes
©
GO TO 5.
No
©
Refer to SC-10, “STARTING SYSTEM”.
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IDX
START SIGNAL
Diagnostic Procedure
EC-623
5
CHECK FUSE
1. Turn ignition switch “OFF”.
2. Disconnect 7.5A fuse.
3. Check if 7.5A fuse is OK.
OK or NG
OK
©
GO TO 6.
NG
©
Replace 7.5A fuse.
6
CHECK START SIGNAL INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Disconnect ignition switch harness connector.
3. Check harness continuity between ECM terminal 42 and fuse block, ignition switch and fuse block. Refer to Wiring Dia-
gram.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK
©
GO TO 8.
NG
©
GO TO 7.
7
DETECT MALFUNCTIONING PART
Check the following.
I
Harness connectors M32, F23
I
Fuse block (J/B) connectors M10, E3
I
Harness for open or short between ignition switch and fuse
I
Harness for open or short between ECM and fuse
©
Repair open circuit or short to ground or short to power in harness or connectors.
8
CHECK INTERMITTENT INCIDENT
Refer to “TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT”, EC-140.
©
INSPECTION END
START SIGNAL
Diagnostic Procedure (Cont’d)
EC-624
System Description
NBEC0392
Sensor
Input Signal to ECM
ECM func-
tion
Actuator
Crankshaft position sensor (POS)
Engine speed (POS signal)
Fuel pump
control
Fuel pump relay
Crankshaft position sensor (REF)
Engine speed (REF signal)
Ignition switch
Start signal
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 120° signal from the crankshaft position sensor (REF), it knows that the
engine is rotating, and causes the pump to operate. If the 120° 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.
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.
SEF018S
Component Description
NBEC0393
The fuel pump with a fuel damper is an in-tank type (the pump and
damper are located in the fuel tank).
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0394
Specification data are reference values.
MONITOR ITEM
CONDITION
SPECIFICATION
FUEL PUMP RLY
I
Ignition switch is turned to ON. (Operates for 1 second.)
I
Engine running and cranking
ON
Except as shown above
OFF
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FUEL PUMP
System Description
EC-625
ECM Terminals and Reference Value
=NBEC0686
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.
TERMI-
NAL
NO.
WIRE
COLOR
ITEM
CONDITION
DATA (DC Voltage)
28
R/L
Fuel pump relay
[Ignition switch “ON”]
I
For 1 second after turning ignition switch “ON”
[Engine is running]
0 - 1.5V
[Ignition switch “ON”]
I
1 second passed after turning ignition switch
“ON”.
BATTERY VOLTAGE
(11 - 14V)
FUEL PUMP
ECM Terminals and Reference Value
EC-626
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