ignition INFINITI QX56 2004 Factory Service Manual

EC-116Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
Generic Scan Tool (GST) FunctionUBS00H06
DESCRIPTION
Generic Scan Tool (OBDII scan tool) complying with SAE J1978 has
8 different functions explained below.
ISO9141 is used as the protocol.
The name “GST” or “Generic Scan Tool” is used in this service man-
ual.
FUNCTION
INSPECTION PROCEDURE
1. Turn ignition switch OFF.
SEF 1 39 P
Diagnostic test mode Function
MODE 1 READINESS TESTSThis mode gains access to current emission-related data values, including analog inputs
and outputs, digital inputs and outputs, and system status information.
MODE 2 (FREEZE DATA)This mode gains access to emission-related data value which were stored by ECM during
the freeze frame. For details, refer to EC-54, "
FREEZE FRAME DATA AND 1ST TRIP
FREEZE FRAME DATA" .
MODE 3 DTCsThis mode gains access to emission-related power train trouble codes which were stored
by ECM.
MODE 4 CLEAR DIAG INFOThis mode can clear all emission-related diagnostic information. This includes:

Clear number of diagnostic trouble codes (MODE 1)

Clear diagnostic trouble codes (MODE 3)

Clear trouble code for freeze frame data (MODE 1)

Clear freeze frame data (MODE 2)

Reset status of system monitoring test (MODE 1)

Clear on board monitoring test results (MODE 6 and 7)
MODE 6 (ON BOARD TESTS)This mode accesses the results of on board diagnostic monitoring tests of specific com-
ponents/systems that are not continuously monitored.
MODE 7 (ON BOARD TESTS)This mode enables the off board test drive to obtain test results for emission-related pow-
ertrain components/systems that are continuously monitored during normal driving condi-
tions.
MODE 8 —This mode can close EVAP system in ignition switch ON position (Engine stopped). When
this mode is performed, the following parts can be opened or closed.

EVAP canister vent control valve open
In the following conditions, this mode cannot function.

Low ambient temperature

Low battery voltage

Engine running

Ignition switch OFF

Low fuel temperature

Too much pressure is applied to EVAP system
MODE 9 (CALIBRATION ID)This mode enables the off-board test device to request specific vehicle information such
as Vehicle Identification Number (VIN) and Calibration IDs.

TROUBLE DIAGNOSIS
EC-117
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Revision: August 20072004 QX56
2. Connect GST to data link connector, which is located under LH
dash panel near the center console.
3. Turn ignition switch ON.
4. Enter the program according to instruction on the screen or in
the operation manual.
(*: Regarding GST screens in this section, sample screens are
shown.)
5. Perform each diagnostic mode according to each service proce-
dure.
For further information, see the GST Operation Manual of
the tool maker.
BBIA0369E
SEF 3 98 S
SEF 4 16 S

EC-118Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
CONSULT-II Reference Value in Data MonitorUBS00H07
Remarks:

Specification data are reference values.

Specification data are output/input values which are detected or supplied by the ECM at the connector.
* Specification data may not be directly related to their components signals/values/operations.
i.e. Adjust ignition timing with a timing light before monitoring IGN TIMING, because the monitor may show the specification data i n
spite of the ignition timing not being adjusted to the specification data. This IGN TIMING monitors the data calculated by the ECM
according to the signals input from the camshaft position sensor and other ignition timing related sensors.
MONITOR ITEM CONDITION SPECIFICATION
ENG SPEED

Run engine and compare the CONSULT-II value with tachometer indica-
tion.Almost the same speed as the
tachometer indication.
MAS A/F SE-B1

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle Approx. 1.1 - 1.4V
2,500 rpm Approx. 1.7 - 2.0V
B/FUEL SCHDL

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 3.0 - 4.2 msec
2,000 rpm 3.0 - 4.2 msec
A/F ALPHA-B1
A/F ALPHA-B2

Engine: After warming upMaintaining engine speed at 2,000
rpm54% - 155%
COOLAN TEMP/S

Engine: After warming up More than 70°C (158°F)
A/F SEN1 (B1)
A/F SEN1 (B2)

Engine: After warming upMaintaining engine speed at 2,000
rpmFluctuated around 1.5V
HO2S2 (B1)
HO2S2 (B2)

Warm-up condition

After keeping engine speed
between 3,500 and 4,000 rpm for
1 minute and at idle for 1 minute
under no load.Revving engine from idle to 3,000 rpm
quickly.0 - 0.3V ←→ Approx. 0.6 -
1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2)

Warm-up condition

After keeping engine speed
between 3,500 and 4,000 rpm for
1 minute and at idle for 1 minute
under no load.Revving engine from idle to 3,000 rpm
quickly.LEAN ←→ RICH
VEH SPEED SE

Turn drive wheels and compare the CONSULT-II value with speedometer
indication.Almost the same speed as the
speedometer indication
BATTERY VOLT

Ignition switch: ON (Engine stopped) 11 - 14V
ACCEL SEN1

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released 0.5 - 1.0V
Accelerator pedal: Fully depressed 4.0 - 4.7V
ACCEL SEN2*

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released 0.3 - 1.2V
Accelerator pedal: Fully depressed 3.9 - 4.8V
THRTL SEN1
THRTL SEN2*

Ignition switch: ON
(Engine stopped)

Shift lever: DAccelerator pedal: Fully released More than 0.36V
Accelerator pedal: Fully depressed Less than 4.75V
EVAP SYS PRES

Ignition switch: ON Approx. 1.8 - 4.8V
START SIGNAL

Ignition switch: ON → START → ON OFF → ON → OFF
CLSD THL POS

Ignition switch: ON
(Engine stopped)Accelerator pedal: Fully released ON
Accelerator pedal: Slightly depressed OFF
AIR COND SIG

Engine: After warming up, idle
the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates.)ON
P/N POSI SW

Ignition switch: ONShift lever: P or N ON
Shift lever: Except above OFF

TROUBLE DIAGNOSIS
EC-119
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Revision: August 20072004 QX56
PW/ST SIGNAL
Engine: After warming up, idle
the engineSteering wheel is in neutral position.
(Forward direction)OFF
Steering wheel is turned. ON
LOAD SIGNAL

Ignition switch: ONRear window defogger switch is ON
and/or lighting switch is in 2nd.ON
Rear window defogger switch is OFF
and lighting switch is OFF.OFF
IGNITION SW

Ignition switch: ON → OFF → ON ON → OFF → ON
HEATER FAN SW

Engine: After warming up, idle
the engineHeater fan is operating. ON
Heater fan is not operating OFF
BRAKE SW

Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
INJ PULSE-B1
INJ PULSE-B2

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 2.0 - 2.8 msec
2,000 rpm 1.9 - 2.9 msec
IGN TIMING

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 14° - 18° BTDC
2,000 rpm 25° - 45° BTDC
CAL/LD VALUE

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 14% - 33%
2,500 rpm 12% - 25%
MASS AIRFLOW

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle 3.0 - 9.0 g·m/s
2,500 rpm 9.0 - 28.0 g·m/s
PURG VOL C/V

Engine: After warming up

Air conditioner switch: OFF

Shift lever: N

no loadIdle
(Accelerator pedal is not depressed
even slightly, after starting engine)0%
2,000 rpm —
AIR COND RLY

Engine: After warming up, idle
the engineAir conditioner switch: OFF OFF
Air conditioner switch: ON
(Compressor operates)ON
FUEL PUMP RLY

For 1 second after turning ignition switch ON

Engine running or crankingON

Except above conditions OFF
VENT CONT/V

Ignition switch: ON OFF
THRTL RELAY

Ignition switch: ON ON
COOLING FAN

Engine: After warming up, idle
the engine

Air conditioner switch: OFFEngine coolant temperature is 99°C
(210°F) or lessOFF
Engine coolant temperature is
between 100°C (212°F) and 104°C
(219°F) at vehicle speed less than 40
km/h (25 MPH)ON
Engine coolant temperature is 105°C
(221°F) or moreON MONITOR ITEM CONDITION SPECIFICATION

EC-120Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
*: Accelerator pedal position sensor 2 signal and throttle position sensor 2 signal are converted by ECM internally. Thus, they differ from
ECM terminals voltage signal.HO2S2 HTR (B1)
HO2S2 HTR (B2)

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 loadON

Engine speed: Above 3,600 rpm OFF
I/P PULLY SPD

Vehicle speed: More than 20 km/h (12 MPH)Almost the same speed as the
tachometer indication
VEHICLE SPEED

Turn drive wheels and compare the CONSULT-II value with speedometer
indication.Almost the same speed as the
speedometer indication
TRVL AFTER MIL

Ignition switch: ONVehicle has traveled after MIL has
turned ON.0 - 65,535 km
(0 - 40,723 miles)
AC PRESS SEN

Ignition switch: ON (Engine stopped) Approx. 0V

Engine: Idle

Air conditioner switch: OFF1.0 - 4.0V
VEH SPEED SE

Turn drive wheels and compare the CONSULT-II value with speedometer
indication.Almost the same speed as the
speedometer indication
SET VHCL SPD

Engine: Running ASCD: Operating.The preset vehicle speed is
displayed.
MAIN SW

Ignition switch: ONON/OFF(MAIN) switch: Pressed ON
ON/OFF(MAIN) switch: Released OFF
CANCEL SW

Ignition switch: ONCANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW

Ignition switch: ONACCEL/RESUME switch: Pressed ON
ACCEL/RESUME switch: Released OFF
SET SW

Ignition switch: ONCOAST/SET switch: Pressed ON
COAST/SET switch: Released OFF
DIST SW

Ignition switch: ONDISTANCE switch: Pressed ON
DISTANCE switch: Released OFF
BRAKE SW1

Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2

Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
CRUISE LAMP

Ignition switch: ONON/OFF(MAIN) switch: Pressed at the
1st time → at the 2nd timeON → OFF
SET LAMP

CRUISE switch: ON

When vehicle switch is between
40 km/h (25 MPH) and 144 km/h
(89 MPH).COAST/SET switch: Pressed ON
COAST/SET switch: Released OFF MONITOR ITEM CONDITION SPECIFICATION

TROUBLE DIAGNOSIS
EC-121
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Major Sensor Reference Graph in Data Monitor ModeUBS00H08
The following are the major sensor reference graphs in “DATA MONITOR” mode.
CLSD THL POS, ACCEL SEN 1, THRTL SEN 1
Below is the data for “CLSD THL POS”, “ACCEL SEN 1” and “THRTL SEN 1” when depressing the accelera-
tor pedal with the ignition switch ON and with selector lever in D position.
The signal of “ACCEL SEN 1” and “THRTL SEN 1” should rise gradually without any intermittent drop or rise
after “CLSD THL POS” is changed from “ON” to “OFF”.
ENG SPEED, MAS A/F SE-B1, THRTL SEN 1, HO2S2 (B1), INJ PULSE-B1
Below is the data for “ENG SPEED”, “MAS A/F SE-B1”, “THRTL SEN 1”, “HO2S2 (B1)”, and “INJ PULSE-B1”
when revving engine quickly up to 4,800 rpm under no load after warming up engine sufficiently.
Each value is for reference, the exact value may vary.
PBIB0198E
SEF 2 41 Y

POWER SUPPLY AND GROUND CIRCUIT
EC-129
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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 ProcedureUBS00H0G
1. INSPECTION START
Start engine.
Is engine running?
Ye s o r N o
Yes >> GO TO 9.
No >> GO TO 2.
2. CHECK 10A FUSE
1. Turn ignition switch OFF.
2. Check 10A fuse (No. 59, located in the fuse and relay box).
OK or NG
OK >> Reinstall fuse. GO TO 3.
NG >>

Repair harness or connectors

Replace fuse
3. CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 109 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
1 B ECM ground[Engine is running]

Idle speedBody ground
109 B/R Ignition switch[Ignition switch: OFF]0V
[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
111 W / BECM relay
(Self shut-off)[Engine is running]
[Ignition switch: OFF]

For a few seconds after turning ignition
switch OFF0 - 1.5V
[Ignition switch: OFF]

More than a few seconds after turning igni-
tion switch OFFBATTERY VOLTAGE
(11 - 14V)
11 5
11 6B
B/WECM ground[Engine is running]

Idle speedBody ground
11 9
120BR
BRPower supply for ECM[Ignition switch: ON]BATTERY VOLTAGE
(11 - 14V)
Voltage: Battery voltage
MBIB0015E

EC-130Revision: August 2007
POWER SUPPLY AND GROUND CIRCUIT
2004 QX56
4. DETECT MALFUNCTIONING PART
Check the following.

10A fuse

Harness for open or short between ECM and ignition switch
>> Repair harness or connectors.
5. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Repair or replace ground connections.
6. CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminals 1, 115, 116 and body ground.
Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors F32, E2

Harness for open or short between ECM and body ground
>> Repair open circuit or short to power in harness or connectors.
BBIA0354E
Continuity should exist.

POWER SUPPLY AND GROUND CIRCUIT
EC-131
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8. CHECK ECM POWER SUPPLY CIRCUIT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ON.
3. Check voltage between IPDM E/R terminal 4 and ground with
CONSULT-II or tester.
OK or NG
OK >> Go to EC-583, "IGNITION SIGNAL" .
NG >> GO TO 9.
9. CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and then OFF.
3. Check voltage between ECM terminals 119, 120 and ground
with CONSULT-II or tester.
OK or NG
OK >> GO TO 17.
NG (Battery voltage does not exist.)>>GO TO 10.
NG (Battery voltage exists for more than a few seconds.)>>GO TO
17.
10. CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Check voltage between ECM terminal 111 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 11.
NG >> GO TO 12.Voltage: Battery voltage
PBIB2063E
Voltage: After turning ignition switch OFF, battery
voltage will exist for a few seconds, then
drop approximately 0V.
PBIB1630E
Voltage: Battery voltage
PBIB11 91 E

EC-132Revision: August 2007
POWER SUPPLY AND GROUND CIRCUIT
2004 QX56
11 . CHECK ECM POWER SUPPLY CIRCUIT-V
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E119.
3. Check harness continuity between ECM terminals 119, 120 and IPDM E/R terminal 3.
Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 14.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
12. CHECK ECM POWER SUPPLY CIRCUIT-VI
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E119.
3. Check harness continuity between ECM terminal 111 and IPDM E/R terminal 7.
Refer to Wiring Diagram.
4. 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.
13. CHECK 20A FUSE
Check 20A fuse (No. 53, located in the IPDM E/R).
OK or NG
OK >> GO TO 17.
NG >> Replace 20A fuse.
14. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
Refer to EC-133, "
Ground Inspection" .
OK or NG
OK >> GO TO 15.
NG >> Repair or replace ground connections.Continuity should exist.
Continuity should exist.
BBIA0354E