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TROUBLE DIAGNOSIS
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6. PERFORM IDLE AIR VOLUME LEARNING
Refer to EC-44, "
Idle Air Volume Learning" .
Is Idle Air Volume Learning carried out successfully?
Ye s o r N o
Yes >> GO TO 7.
No >> 1. Follow the instruction of Idle Air Volume Learning.
2. GO TO 4.
7. CHECK TARGET IDLE SPEED AGAIN
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Read idle speed in “DATA MONITOR” mode with CONSULT-II.
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Check idle speed.
OK or NG
OK >> GO TO 10.
NG >> GO TO 8.
8. DETECT MALFUNCTIONING PART
Check the following.
Check camshaft position sensor (PHASE) and circuit. Refer to EC-261 .
Check crankshaft position sensor (POS) and circuit. Refer to EC-255 .
OK or NG
OK >> GO TO 9.
NG >> 1. Repair or replace.
2. GO TO 4.
9. CHECK ECM FUNCTION
1. Substitute another known-good ECM to check ECM function. (ECM may be the cause of an incident, but
this is a rare case.)
2. Perform initialization of IVIS (NATS) system and registration of all IVIS (NATS) ignition key IDs. Refer to
BL-138, "
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-NATS)" .
>> GO TO 4. 650 ± 50 rpm (in P or N position)
650 ± 50 rpm (in P or N position)
Page 1275 of 3371

EC-84Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
Symptom Matrix ChartUBS00H00
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel pump circuit 1 1 2 3 2 2 2 3 2EC-601
Fuel pressure regulator system 3 3 4 4 4 4 4 4 4 4EC-46
Injector circuit 1 1 2 3 2 2 2 2EC-595
Evaporative emission system 3 3 4 4 4 4 4 4 4 4EC-633
Air Positive crankcase ventilation sys-
tem
334444444 41EC-645
Incorrect idle speed adjustment 1 1 1 1 1EC-79
Electric throttle control actuator 1 1 2 3 3 2 2 2 2 2 2EC-365,
EC-367
Ignition Incorrect ignition timing adjustment 3 3 1 1 1 1 1 1EC-79
Ignition circuit 1 1 2 2 2 2 2 2EC-583
Main power supply and ground circuit 2 2 3 3 3 3 3 2 3EC-128
Mass air flow sensor circuit
1
122
222 2EC-146,
EC-154
Engine coolant temperature sensor circuit
333EC-165,
EC-178
A/F sensor 1 circuitEC-429
,
EC-437
,
EC-445
,
EC-454
,
EC-463
,
EC-472
,
EC-484
Throttle position sensor circuit
22EC-171
,
EC-236
,
EC-420
,
EC-422
,
EC-569
Accelerator pedal position sensor circuit 3 2 1EC-424
,
EC-556
,
EC-562
,
EC-576
Knock sensor circuit 2 3EC-250
Crankshaft position sensor (POS) circuit 2 2EC-255
Camshaft position sensor (PHASE) circuit 3 2EC-261
Page 1276 of 3371

TROUBLE DIAGNOSIS
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1 - 6: The numbers refer to the order of inspection.
(continued on next page)
SYSTEM — ENGINE MECHANICAL & OTHER
Vehicle speed signal circuit 2 3 3 3EC-340
Power steering pressure sensor circuit 2 3 3EC-346
ECM 22333333333EC-351,
EC-361
PNP switch circuit 3 3 3 3 3EC-546
Refrigerant pressure sensor circuit 2 3 3 4EC-607
Electrical load signal circuit 3EC-612
Air conditioner circuit 2 2 3 3 3 3 3 3 3 3 2AT C - 3 3
ABS actuator and electric unit (control unit) 4BRC-11
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Fuel tank
5
5FL-9
Fuel piping 5 5 5 5 5 5FL-3
Vapor lock—
Valve deposit
555555 5—
Poor fuel (Heavy weight gaso-
line, Low octane)—
Page 1287 of 3371

EC-96Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
ECM Harness Connector Terminal LayoutUBS00H03
ECM Terminals and Reference ValueUBS00H04
PREPARATION
1. ECM is located in the engine room passenger side behind bat-
tery.
2. Remove ECM harness connector.
3. When disconnecting ECM harness connector, loosen it with
levers as far as they will go as shown in the figure.
4. Connect a break-out box (SST) and Y-cable adapter (SST)
between the ECM and ECM harness connector.
Use extreme care not to touch 2 pins at one time.
Data is for comparison and may not be exact.
ECM INSPECTION TABLE
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.
PBIB1192E
BBIA0386E
BBIA0387E
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 B ECM ground[Engine is running]
Idle speedBody ground
2O/BA/F sensor 1 heater
(bank 1)[Engine is running]
Warm-up condition
Idle speedApproximately 5V
PBIB1584E
Page 1288 of 3371
![INFINITI QX56 2004 Factory Service Manual TROUBLE DIAGNOSIS
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Revision: August 20072004 QX563LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor INFINITI QX56 2004 Factory Service Manual TROUBLE DIAGNOSIS
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Revision: August 20072004 QX563LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor](/manual-img/42/57034/w960_57034-1287.png)
TROUBLE DIAGNOSIS
EC-97
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Revision: August 20072004 QX563LThrottle control motor relay
power supply[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
4 L/W Throttle control motor (Close)[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Released0 - 14V
5 L/B Throttle control motor (Open)[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Fully depressed0 - 14V
6GRHeated oxygen sensor 2
heater (bank 1)[Engine is running]
Engine speed is below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load0 - 1.0V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed is above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
12 RPower steering pressure
sensor[Engine is running]
Steering wheel is being turned.0.5 - 4.5V
[Engine is running]
Steering wheel is not being turned.0.4 - 0.8V
13 OCrankshaft position sensor
(POS)[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.1.0 - 2.0V
[Engine is running]
Engine speed is 2,000 rpm.1.0 - 2.0V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB1104E
PBIB1105E
PBIB1041E
PBIB1042E
Page 1289 of 3371
![INFINITI QX56 2004 Factory Service Manual EC-98Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
14 YCamshaft position sensor
(PHASE)[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.1 INFINITI QX56 2004 Factory Service Manual EC-98Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
14 YCamshaft position sensor
(PHASE)[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.1](/manual-img/42/57034/w960_57034-1288.png)
EC-98Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
14 YCamshaft position sensor
(PHASE)[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.1.0 - 4.0V
[Engine is running]
Engine speed is 2,000 rpm.1.0 - 4.0V
15 W Knock sensor 1[Engine is running]
Idle speedApproximately 2.5V
16 BR/R
A/F sensor 1 (bank 1)[Engine is running]
Warm-up condition
Idle speedApproximately 3.1V
35 BR/GApproximately 2.6V
56 LG/BApproximately 2.3V
75 P/BApproximately 2.3V
21
22
23
40
41
42
44
63O/L
BR
GR/W
Y/G
P
L
O
GInjector No. 5
Injector No. 3
Injector No. 1
Injector No. 6
Injector No. 4
Injector No. 2
Injector No. 7
Injector No. 8[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed is 2,000 rpm.BATTERY VOLTAGE
(11 - 14V)
24 BR/WA/F sensor 1 heater
(bank 2)[Engine is running]
Warm-up condition
Idle speedApproximately 5V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB1039E
PBIB1040E
PBIB0042E
PBIB0043E
PBIB1584E
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![INFINITI QX56 2004 Factory Service Manual TROUBLE DIAGNOSIS
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25 O/GHeated oxygen sensor 2
heater (bank 2)[Engine is running]
Engine speed is below 3,600 rpm after the
following INFINITI QX56 2004 Factory Service Manual TROUBLE DIAGNOSIS
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Revision: August 20072004 QX56
25 O/GHeated oxygen sensor 2
heater (bank 2)[Engine is running]
Engine speed is below 3,600 rpm after the
following](/manual-img/42/57034/w960_57034-1289.png)
TROUBLE DIAGNOSIS
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25 O/GHeated oxygen sensor 2
heater (bank 2)[Engine is running]
Engine speed is below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load.0 - 1.0V
[Ignition switch: ON]
Engine stopped
[Engine is running]
Engine speed is above 3,600 rpm.BATTERY VOLTAGE
(11 - 14V)
32 LEVAP control system pres-
sure sensor[Ignition switch: ON]Approximately 1.8 - 4.8V
34 R/BIntake air temperature sen-
sor[Engine is running]Approximately 0 - 4.8V
Output voltage varies with intake
air temperature.
36 W Knock sensor 2[Engine is running]
Idle speedApproximately 2.5V
45 L/YEVAP canister purge volume
control solenoid valve[Engine is running]
Idle speed
Accelerator pedal is not depressed even
slightly, after starting engine.BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Engine speed is about 2,000 rpm (More
than 100 seconds after starting engine).11 - 14V
46
60
61
62
65
79
80
81L/R
GR/R
O/W
Y/R
G/R
V/W
W/R
W/GIgnition signal No. 7
Ignition signal No. 5
Ignition signal No. 3
Ignition signal No. 1
Ignition signal No. 8
Ignition signal No. 6
Ignition signal No. 4
Ignition signal No. 2[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle.0 - 0.2V
[Engine is running]
Warm-up condition
Engine speed is 2,000 rpm.0.1 - 0.4V
47 YSensor power supply
(Throttle position sensor)[Ignition switch: ON]Approximately 5V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
PBIB0050E
PBIB0051E
PBIB0044E
PBIB0045E
Page 1291 of 3371
![INFINITI QX56 2004 Factory Service Manual EC-100Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
48 SBSensor power supply
(EVAP control system pres-
sure sensor)[Ignition switch: ON]Approximately 5V
49 R/YSensor power supply
(Refrigerant pre INFINITI QX56 2004 Factory Service Manual EC-100Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
48 SBSensor power supply
(EVAP control system pres-
sure sensor)[Ignition switch: ON]Approximately 5V
49 R/YSensor power supply
(Refrigerant pre](/manual-img/42/57034/w960_57034-1290.png)
EC-100Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
48 SBSensor power supply
(EVAP control system pres-
sure sensor)[Ignition switch: ON]Approximately 5V
49 R/YSensor power supply
(Refrigerant pressure sen-
sor)[Ignition switch: ON]Approximately 5V
50 B Throttle position sensor 1[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Fully releasedMore than 0.36V
[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Fully depressedLess than 4.75V
51 W Mass air flow sensor[Engine is running]
Warm-up condition
Idle speed1.1 - 1.4V
[Engine is running]
Warm-up condition
Engine speed is 2,500 rpm.1.7 - 2.0V
55 RHeated oxygen sensor 2
(bank 1)[Engine is running]
Warm-up condition
Revving engine from idle to 3,000 rpm
quickly after the following conditions are
met.
–After keeping the engine speed between
3,500 and 4,000 rpm for 1 minute and at
idle for 1 minute under no load.0 - Approximately 1.0V
57 L/P
A/F sensor 1 (bank 2)[Engine is running]
Warm-up condition
Idle speedApproximately 2.6V
58 GR/GApproximately 2.3V
76 G/LApproximately 3.1V
77 BR/BApproximately 2.3V
66 RSensor ground
(Throttle position sensor)[Engine is running]
Warm-up condition
Idle speedApproximately 0V
67 B Sensor ground[Engine is running]
Warm-up condition
Idle speedApproximately 0V
68 W/LSensor power supply
(Power steering pressure
sensor)[Ignition switch: ON]Approximately 5V
69 W Throttle position sensor 2[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Fully releasedLess than 4.75V
[Ignition switch: ON]
Engine stopped
Shift lever position: D
Accelerator pedal: Fully depressedMore than 0.36V TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)