2004 INFINITI QX56 brake sensor

EC-104Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56

System readiness test (SRT) codes

Test values

Others
ENGINE CONTROL COMPONENT PARTS/CONTROL SYSTEMS APPLICATION
ItemDIAGNOSTIC TEST MODE
WORK
SUP-
PORTSELF-DIAGNOSTIC
RESULTS
DATA
MONI-
TORDATA
MONI-
TOR
(SPEC)ACTIVE
TESTDTC & SRT
CONFIRMATION
DTC*1FREEZE
FRAME
DATA*2SRT
STATUSDTC
WORK
SUP-
PORT
ENGINE CONTROL COMPONENT PARTS
INPUT
Crankshaft position sensor (POS)××××
Camshaft position sensor (PHASE)××××
Mass air flow sensor×××
Engine coolant temperature sensor×××××
A/F sensor 1×××××
Heated oxygen sensor 2×××××
Vehicle speed sensor×× ××
Accelerator pedal position sensor×××
Throttle position sensor×××
Fuel tank temperature sensor××××
EVAP control system pressure
sensor×××
Intake air temperature sensor××× ×
Knock sensor×
Refrigerant pressure sensor××
Closed throttle position switch
(accelerator pedal position sensor
signal)××
Air conditioner switch××
Park/neutral position (PNP) switch×××
Stop lamp switch×××
Power steering pressure sensor×××
Battery voltage××
Load signal××
Fuel level sensor×××
ICC steering switch×××
ASCD steering switch×××
ICC brake switch×××
ASCD brake switch×××

TROUBLE DIAGNOSIS
EC-109
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Revision: August 20072004 QX56P/N POSI SW
[ON/OFF]××
Indicates [ON/OFF] condition from the park/
neutral position (PNP) switch signal.
PW/ST SIGNAL
[ON/OFF]××

[ON/OFF] condition of the power steering sys-
tem (determined by the signal voltage of the
power steering pressure sensor signal) is indi-
cated.
LOAD SIGNAL
[ON/OFF]××

Indicates [ON/OFF] condition from the electri-
cal load signal.
ON: Rear window defogger switch is ON and/
or lighting switch is in 2nd position.
OFF: Both rear window defogger switch and
lighting switch are OFF.
IGNITION SW
[ON/OFF]

Indicates [ON/OFF] condition from ignition
switch signal.
HEATER FAN SW
[ON/OFF]

Indicates [ON/OFF] condition from the heater
fan switch signal.
BRAKE SW
[ON/OFF]

Indicates [ON/OFF] condition from the stop
lamp switch signal.
INJ PULSE-B1
[msec]×

Indicates the actual fuel injection pulse width
compensated by ECM according to the input
signals.
When the engine is stopped, a certain
computed value is indicated.
INJ PULSE-B2
[msec]
IGN TIMING
[BTDC]×

Indicates the ignition timing computed by ECM
according to the input signals.
When the engine is stopped, a certain
value is indicated.
CAL/LD VALUE [%]

“Calculated load value” indicates the value of
the current air flow divided by peak air flow.
MASS AIRFLOW
[g·m/s]

Indicates the mass air flow computed by ECM
according to the signal voltage of the mass air
flow sensor.
PURG VOL C/V
[%]

Indicates the EVAP canister purge volume
control solenoid valve control value computed
by the ECM according to the input signals.

The opening becomes larger as the value
increases.
AIR COND RLY
[ON/OFF]×

The air conditioner relay control condition
(determined by ECM according to the input
signals) is indicated.
FUEL PUMP RLY
[ON/OFF]×

Indicates the fuel pump relay control condition
determined by ECM according to the input sig-
nals.
VENT CONT/V
[ON/OFF]

The control condition of the EVAP canister
vent control valve (determined by ECM
according to the input signals) is indicated.
ON: Closed
OFF: Open
THRTL RELAY
[ON/OFF]

Indicates the throttle control motor relay con-
trol condition determined by the ECM accord-
ing to the input signals.
COOLING FAN
[HI/OFF]

The control condition of the cooling fan (deter-
mined by ECM according to the input signals)
is indicated.
ON: Operating
OFF: Stop Monitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks

EC-110Revision: August 2007
TROUBLE DIAGNOSIS
2004 QX56
HO2S2 HTR (B1)
[ON/OFF]
Indicates [ON/OFF] condition of heated oxy-
gen sensor 2 heater determined by ECM
according to the input signals. HO2S2 HTR (B2)
[ON/OFF]
I/P PULLY SPD
[rpm]

Indicates the engine speed computed from the
turbine revolution sensor signal.
VEHICLE SPEED
[km/h] or [MPH]

Indicates the vehicle speed computed from
the revolution sensor signal.
IDL A/V LEARN
[YET/CMPLT]

Display the condition of idle air volume learn-
ing
YET: Idle air volume learning has not been
performed yet.
CMPLT: Idle air volume learning has already
been performed successfully.
TRVL AFTER MIL
[km] or [mile]

Distance traveled while MIL is activated.
A/F S1 HTR (B1)
[%]

Indicates A/F sensor 1 heater control value
computed by the ECM according to the input
signals.

The current flow to the heater becomes larger
as the value increases. A/F S1 HTR (B2)
[%]
AC PRESS SEN
[V]

The signal voltage from the refrigerant pres-
sure sensor is displayed.
VHCL SPEED SE
[km/h] or [mph]

The vehicle speed computed from the vehicle
speed signal sent from TCM is displayed.
SET VHCL SPD
[km/h] or [mph]

The preset vehicle speed is displayed.
MAIN SW
[ON/OFF]

Indicates [ON/OFF] condition from ON/
OFF(MAIN) switch signal.
CANCEL SW
[ON/OFF]

Indicates [ON/OFF] condition from CANCEL
switch signal.
RESUME/ACC SW
[ON/OFF]

Indicates [ON/OFF] condition from ACCEL/
RESUME switch signal.
SET SW
[ON/OFF]

Indicates [ON/OFF] condition from COAST/
SET switch signal.
DIST SW
[ON/OFF]

Indicates [ON/OFF] condition from DISTANCE
switch signal.
BRAKE SW1 SW
[ON/OFF]

Indicates [ON/OFF] condition from ASCD
brake switch signal.
BRAKE SW2 SW
[ON/OFF]

Indicates [ON/OFF] condition of stop lamp
switch signal.
VHCL SPD CUT
[NON/CUT]

Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the
ASCD set speed.
CUT: Vehicle speed increased to excessively
high compared with the ASCD set speed, and
ASCD operation is cut off.
LOW SPEED CUT
[NON/CUT]

Indicates the vehicle cruise condition.
NON: Vehicle speed is maintained at the
ASCD set speed.
CUT: Vehicle speed decreased to excessively
low compared with the ASCD set speed, and
ASCD operation is cut off. Monitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks

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

EC-464Revision: August 2007
DTC P1276, P1286 A/F SENSOR 1
2004 QX56
If the indication is constantly approx. 1.5V and does not fluctuates, go to EC-469, "Diagnostic Procedure"
.
If the indication fluctuates around 1.5V, go to next step.
4. Select “A/F SEN1 (B1) P1276” or “A/F SEN1 (B2) P1286” of “A/F SEN1” in “DTC WORK SUPPORT”
mode with CONSULT-II.
5. Touch “START”.
6. When the following conditions are met, “TESTING” will be dis-
played on the CONSULT-II screen.
If “TESTING” is not displayed after 20 seconds, retry from
step 2.
7. Release accelerator pedal fully.
NOTE:
Never apply brake during releasing the accelerator pedal.
8. Make sure that “TESTING” changes to “COMPLETED”.
If “TESTING” changed to “OUT OF CONDITION”, retry from
step 6.
9. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULT”.
If “NG” is displayed, go to EC-469, "
Diagnostic Procedure" .
Overall Function CheckUBS00HAB
Use this procedure to check the overall function of the A/F sensor 1 circuit. During this check, a 1st trip DTC
might not be confirmed.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Drive the vehicle at a speed of 80 km/h (50 MPH) for a few minutes in the suitable gear position.
3. Set 5th position, then release the accelerator pedal fully until the vehicle speed decreases to 50 km/h (30
MPH).
NOTE:
Never apply brake during releasing the accelerator pedal.
4. Repeat steps 2 to 3 five times.
5. Stop the vehicle and turn ignition switch OFF.
6. Wait at least 10 seconds and restart engine.
ENG SPEED 850 - 3,200 rpm
Vehicle speed More than 64 km/h (40 MPH)
B/FUEL SCHDL 1.0 - 8.0 msec
Selector lever D position with “OD” ON
SEF 5 76 Z
SEF 5 77 Z
SEF 5 78 Z

AUTOMATIC SPEED CONTROL DEVICE (ASCD)
EC-647
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Revision: August 20072004 QX56
AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionUBS00HE7
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without pressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/h
(25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
SET OPERATION
Press ON/OFF(MAIN) switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press COAST/SET switch. (Then SET indicator in combination meter illuminates.)
ACCEL OPERATION
If the ACCEL/RESUME switch is pressed during cruise control driving, increase the vehicle speed until the
switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.

CANCEL switch is pressed

More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)

Brake pedal is depressed

Selector lever is changed to N, P, R position

Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed

VDC/TCS system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.

Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing COAST/SET switch or ACCEL/
RESUME switch.

Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If ON/OFF(MAIN) switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled
and vehicle speed memory will be erased.
COAST OPERATION
When the COAST/SET switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Park/Neutral position (PNP)
switchGear position
Combination meter* Vehicle speed
TCM* Powertrain revolution

FAX-6
WHEEL HUB
Revision: August 20072004 QX56
4. Put alignment mark on disc rotor and wheel hub and bearing
assembly, then remove disc rotor.
5. Remove cotter pin, then remove lock nut from drive shaft using power tool. Refer to FA X -7 , "
Removal and
Installation" .
6. Remove drive shaft from wheel hub and bearing assembly. Refer to FAX-7, "
Removal and Installation" .
7. Remove wheel sensor. Refer to BRC-64, "
Removal and Installation" .

Inspect the wheel sensor O-ring, replace the wheel sensor assembly if damaged.

Clean the wheel sensor hole and mounting surface with a suitable brake cleaner and clean lint-free
shop rag. Be careful that dirt and debris do not enter the axle bearing area.

Apply a coat of suitable grease to the wheel sensor O-ring and mounting hole.
CAUTION:
Do not pull on the wheel sensor harness.
8. Remove wheel hub and bearing assembly bolts using power tool.
9. Remove splash guard and wheel hub and bearing assembly from steering knuckle.
INSPECTION AFTER REMOVAL
Check for deformity, cracks and damage on each part, replace if necessary.
INSTALLATION
Installation is in the reverse order of removal.

Use new bolts when installing the wheel hub and bearing assembly.

When installing disc rotor on wheel hub and bearing assembly,
position the disc rotor according to alignment mark.
(When not using the alignment mark, refer to BR-22, "
Removal
and Installation of Brake Caliper and Disc Rotor" .)

When installing wheel and tire. Refer to WT-6, "Rotation" .
WDIA0044E
WDIA0044E

DRIVE SHAFT
FAX-7
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Revision: August 20072004 QX56
DRIVE SHAFTPFP:39100
Removal and InstallationEDS001B5
REMOVAL
1. Remove wheel and tire using power tool.
2. Remove engine under cover using power tool.
3. Remove wheel sensor harness from mount on knuckle.
CAUTION:
Do not pull on wheel sensor harness.
4. Without disassembling the hydraulic lines, remove brake caliper using power tool. Reposition it aside with
wire. Refer to BR-22, "
Removal and Installation of Brake Caliper and Disc Rotor" .
NOTE:
Avoid depressing brake pedal while brake caliper is removed.
5. Remove coil spring and shock absorber assembly using power tool. Refer to FSU-10, "
Removal and
Installation" .
6. Separate upper link ball joint stud from steering knuckle using
Tool.

Support lower link with jack.
7. Remove cotter pin, then remove drive shaft nut.
8. Remove drive shaft mounting bolts from front final drive.
9. Remove drive shaft from wheel hub and bearing assembly.
CAUTION:

When removing drive shaft, do not apply an excessive
angle to drive shaft joint. Also be careful not to exces-
sively extend slide joint.
INSPECTION AFTER REMOVAL

Move joint up, down, left, right, and in axial direction. Check for any rough movement or significant loose-
ness.

Check boot for cracks or other damage, and for grease leakage.

If damaged, disassemble drive shaft to verify damage, and
repair or replace as necessary.
1. Cotter pin 2. Drive shaft nut 3. Drive shaft
LDIA0159E
Tool number : ST29020001 (J-24319-01)
LEIA0095E
RAA0030D