2004 INFINITI QX56 ECU

ACS-38
[ICC]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
3. CHECK HARNESS BETWEEN ICC UNIT AND ABS ACTUATOR AND ELECTRIC UNIT (CONTROL
UNIT)
1. Turn ignition switch OFF.
2. Disconnect connectors of ICC unit and ABS actuator and elec-
tric unit (control unit).
3. Check continuity between ICC unit harness connector B13 ter-
minal 10 (V/R) and ABS actuator and electric unit (control unit)
connector E125 terminal 7 (V/R).
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase
DTC and perform ICC system running test. Then per-
form self-diagnosis of ICC system again.
NG >>

Repair harness between ICC unit and ABS actuator and electric unit (control unit).

After repair, erase DTC and perform ICC system running test. Then, perform self-diagnosis of
ICC system again.
DTC 20 CAN COMM CIRCUITEKS007X4
1. CHECK CAN COMMUNICATION
With CONSULT-II
1. Perform self-diagnosis.
2. Print self-diagnostic result.
>> After printing self-diagnostic result, go to “CAN system”. Refer to LAN-3, "
Precautions When
Using CONSULT-II" .
DTC 31 POWER SUPPLY CIR 1, DTC 34 POWER SUPPLY CIR 2EKS007X5
1. CHECK ICC UNIT CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect ICC unit connector and connect it securely again. Then erase DTC. Then perform self-diagno-
sis of ICC system again.
OK or NG
OK >> GO TO 2.
NG >>

Poor connector connection.

Check connector. (Check connector housing for disconnected, loose, bent, and collapsed ter-
minals. If any malfunction is detected, repair applicable part.) After repair, erase DTC, and per-
form ICC running test. Then perform self-diagnosis of ICC system again.
2. CHECK POWER SUPPLY CIRCUIT FOR ICC UNIT
1. Turn ignition switch ON.
2. Check voltage between ICC unit harness connector B17 termi-
nal 33 (R/B), 42 (R/B) and ground.
OK or NG
OK >> GO TO 3.
NG >>

Repair ICC unit power supply harness.

After repair, erase DTC and perform ICC system run-
ning test. Then, perform self-diagnosis of ICC system
again. Continuity should exist.
WKIA2042E
Battery voltage should exist.
SKIA11 73 E

ACS-40
[ICC]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
DTC 45 BRAKE SW/STOP L SWEKS007X8
1. CHECK CONNECTORS FOR ICC UNIT
1. Turn ignition switch OFF.
2. Disconnect ICC unit connectors, and connect them securely again. Then erase DTC. Then, perform self-
diagnosis of ICC system again.
OK or NG
OK >>
Poor connector connection.

Check connectors. (Check connectors housing for disconnected, loose, bent, and collapsed
terminals. If any malfunction is detected, repair applicable part.) After repair, erase DTC, and
perform ICC system running test. Then perform self-diagnosis of ICC system again.
NG >> GO TO 2.
2. CHECK STOP LAMP SWITCH AND ICC BRAKE SWITCH
With CONSULT-II

With data monitor, check if “STOP LAMP SW” and “BRAKE SW” are operating normally.
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase DTC and perform ICC system running
test. Then perform self-diagnosis of ICC system again.
NG >>

BRAKE SW: GO TO 3.

STOP LAMP SW: GO TO 5.
3. ICC BRAKE SWITCH INSTALLATION AND ADJUSTMENT INSPECTION

Check ICC brake switch for proper installation and adjust if necessary. Refer to BR-6, "BRAKE PEDAL" .
OK or NG
OK >> GO TO 4.
NG >> After adjustment, erase DTC and perform ICC system running test. Then perform self-diagnosis
of ICC system again.
4. CHECK ICC BRAKE SWITCH

Check ICC brake switch. Refer to ACS-58, "ICC Brake Switch and Stop Lamp Switch" .
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase DTC and perform ICC system running
test. Then perform self-diagnosis of ICC system again.
NG >> Replace ICC brake switch. Erase DTC and perform ICC system running test. Then perform self-
diagnosis of ICC system again.
5. CHECK STOP LAMP ILLUMINATION

Check stop lamp illumination.
OK or NG
OK >> GO TO 6.
NG >>

Check stop lamp circuit.

After repair, erase DTC and perform ICC system running test. Then, perform self-diagnosis of
ICC system again.

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
ACS-41
[ICC]
C
D
E
F
G
H
I
J
L
MA
B
ACS
Revision: August 20072004 QX56
6. CHECK ICC BRAKE HOLD RELAY
1. Turn ignition switch OFF.
2. Remove ICC brake hold relay.
3. Check continuity between terminals of ICC brake hold relay.
OK or NG
OK >> GO TO 7.
NG >> Replace ICC brake hold relay. Erase DTC and perform
ICC system running test. Then perform self-diagnosis of
ICC system again.
7. CHECK ICC BRAKE HOLD RELAY CIRCUIT
1. Disconnect connectors of ICC unit and stop lamp switch.
2. Check continuity between ICC unit harness connector B17 ter-
minal 38 (R/G) and ICC brake hold relay harness connector
E134 terminal 7 (R/G).
3. Check continuity between ICC unit harness connector B17 ter-
minal 38 (R/G) and stop lamp switch harness connector E38 ter-
minal 4 (R/G).
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase
DTC and perform ICC system running test. Then perform self-diagnosis of ICC system again.
NG >>

Repair harness between ICC unit and ICC brake hold relay or stop lamp switch.

After repair, erase DTC and perform ICC system running test. Then, perform self-diagnosis of
ICC system again.
DTC 46 OPERATION SW CIRCEKS007X9
1. CHECK ECM CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect ECM connector, and connect it securely again. Then erase DTC. Then, perform self-diagnosis
of ICC system again.
OK or NG
OK >>
Poor connector connection.

Check connector. (Check connector housing for disconnected, loose, bent, and collapsed ter-
minals. If any malfunction is detected, repair applicable part.) After repair, erase DTC, and per-
form ICC system running test. Then perform self-diagnosis of ICC system again.
NG >> GO TO 2.
2. CHECK ICC STEERING SWITCH

Check ICC steering switch. Refer to ACS-58, "ICC Steering Switch" .
OK or NG
OK >> GO TO 3.
NG >> Replace ICC steering switch assembly. Refer to ACS-59, "
ICC Steering Switch" . Erase DTC and
perform ICC system running test. Then perform self-diagnosis of ICC system again. 7 - 6 Continuity should not exist.
4 - 3 Continuity should exist.
SKIA6651E
Continuity should exist.
Continuity should exist.
WKIA3403E

ACS-48
[ICC]
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 QX56
DTC 96 NP RANGEEKS007XH
1. CHECK ICC UNIT CONNECTORS
1. Turn ignition switch OFF.
2. Disconnect ICC unit harness connectors and connect them securely again. Then erase DTC. Then, per-
form self-diagnosis of ICC system again.
OK or NG
OK >> GO TO 2.
NG >>

Poor connector connection.

Check connector. (Check connector housing for disconnected, loose, bent, and collapsed ter-
minals. If any malfunction is detected, repair applicable part.) After repair, erase DTC, and per-
form ICC system running test. Then perform self-diagnosis of ICC system again.
2. CHECK NP RANGE SWITCH SIGNAL
With CONSULT-II

With data monitor, check that “NP RANGE SW” operates normally.
OK or NG
OK >> Perform TCM diagnosis. Refer to AT-93, "SELF-DIAGNOSTIC RESULT MODE" .
NG >> GO TO 3.
3. CHECK HARNESS BETWEEN ICC UNIT AND TCM
1. Turn ignition switch OFF.
2. Disconnect ICC unit harness connectors and A/T assembly har-
ness connector.
3. Check continuity between ICC unit harness connector B13 ter-
minal 7 (B/R) and A/T assembly harness connector F9 terminal
9 (B/R).
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase
DTC and perform ICC system running test. Then per-
form self-diagnosis of ICC system again.
NG >>

Repair harness between ICC unit and TCM.

After repair, erase DTC and perform ICC system running test. Then, perform self-diagnosis of
ICC system again.
DTC 97 AT CIRCUITEKS007XI
1. CHECK AT CIRCUIT
With CONSULT-II

With TCM diagnosis, check that shift operates normally. Refer to AT-109, "DTC P0705 PARK/NEUTRAL
POSITION SWITCH" .
OK or NG
OK >> Replace ICC unit. Refer to ACS-59, "ICC Unit" . Erase DTC and perform self-diagnosis of ICC
system again.
NG >>

Perform TCM diagnosis.

After repair, erase DTC and perform self-diagnosis of ICC system again.
7 - 9 Continuity should exist.
SKIA5982E

PRECAUTIONS
AT-7
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
UCS002C1
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WA RN ING:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for On Board Diagnostic (OBD) System of A/T and EngineUCS002C2
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:

Be sure to turn the ignition switch “OFF” and disconnect the negative battery cable before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves,
etc. Will cause the MIL to light up.

Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to an open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)

Be sure to route and secure the harnesses properly after work. Interference of the harness with a
bracket, etc. May cause the MIL to light up due to a short circuit.

Be sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to a malfunction of the EGR system or fuel injection system, etc.

Be sure to erase the unnecessary malfunction information (repairs completed) from the TCM and
ECM before returning the vehicle to the customer.

AT-58
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Inspections Before Trouble DiagnosisUCS002CX
A/T FLUID CHECK
Fluid Leakage and Fluid Level Check

Inspect for fluid leakage and check the fluid level. Refer to AT - 1 3 , "Checking A/T Fluid" .
Fluid Condition Check
Inspect the fluid condition.
STALL TEST
Stall Test Procedure
1. Inspect the amount of engine oil. Replenish the engine oil if necessary.
2. Drive for about 10 minutes to warm up the vehicle so that the A/
T fluid temperature is 50 to 80°C (122 to 176°F). Inspect the
amount of ATF. Replenish if necessary.
3. Securely engage the parking brake so that the tires do not turn.
4. Engine start, apply foot brake, and place selector lever in “D”
position.
5. While holding down the foot brake, gradually press down the
accelerator pedal.
6. Quickly read off the stall speed, then quickly remove your foot
from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 sec-
onds during this test.
7. Move the selector lever to the “N” position.
8. Cool down the ATF.
Fluid condition Conceivable Cause Required Operation
Varnished (viscous
varnish state)Clutch, brake
scorchedReplace the ATF and check the A/T
main unit and the vehicle for mal-
functions (wire harnesses, cooler
pipes, etc.)
Milky white or
cloudyWater in the fluidReplace the ATF and check for
places where water is getting in.
Large amount of
metal powder mixed
inUnusual wear of
sliding parts within
A/TReplace the ATF and check for
improper operation of the A/T.
SAT6 3 8A
SAT6 4 7B
SCIA1224E
SAT5 1 4G

AT-60
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
3. After warming up remove the oil pressure detection plug and
install the oil pressure gauge [ST2505S001(J34301-C)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-
ring attached to the oil pressure detection plug.
4. Securely engage the parking brake so that the tires do not turn.
5. Start the engine, then measure the line pressure at both idle and
the stall speed.
CAUTION:

Keep the brake pedal pressed all the way down during
measurement.

When measuring the line pressure at the stall speed,
refer to AT-5 8, "
STALL TEST" .
6. After the measurements are complete, install the oil pressure
detection plug and tighten to the regulation torque below.
CAUTION:
Do not reuse the O-ring.
Line Pressure
SCIA0504E
SCIA1224E
:7.3 N·m (0.74 kg-m, 65 in-lb)SAT4 9 3G
Engine speedLine pressure [kPa (kg/cm
2 , psi)]
R position D position
At idle speed 392 - 441 (4.0 - 4.5, 57 - 64) 373 - 422 (3.8 - 4.3, 54 - 61)
At stall speed 1,700 - 1,890 (17.3 - 19.3, 247 - 274) 1,310 - 1,500 (13.3 - 15.3, 190 - 218)

TROUBLE DIAGNOSIS
AT-91
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
CONSULT-II Function (A/T)UCS002D8
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II REFERENCE VALUE
NOTICE:
1. The CONSULT-II electrically displays shift timing and lock-up timing (that is, operation timing of each sole-
noid).
Check for time difference between actual shift timing and the CONSULT-II display. If the difference is
noticeable, mechanical parts (except solenoids, sensors, etc.) may be malfunctioning. Check mechanical
parts using applicable diagnostic procedures.
2. Shift schedule (which implies gear position) displayed on CONSULT-II and that indicated in Service Man-
ual may differ slightly. This occurs because of the following reasons:
–Actual shift schedule has more or less tolerance or allowance,
–Shift schedule indicated in Service Manual refers to the point where shifts start, and
–Gear position displayed on CONSULT-II indicates the point where shifts are completed.
3. Display of solenoid valves on CONSULT-II changes at the start of shifting, while gear position is displayed
upon completion of shifting (which is computed by TCM).
TCM diagnostic mode Description
WORK SUPPORTSupports inspections and adjustments. Commands are transmitted to the TCM for setting the status
suitable for required operation, input/output signals are received from the TCM and received data is
displayed.
SELF-DIAG RESULTS Displays TCM self-diagnosis results.
DATA MONITOR Displays TCM input/output data in real time.
CAN DIAG SUPPORT MNTR The result of transmit/receive diagnosis of CAN communication can be read.
ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
FUNCTION TESTConducted by CONSULT-II instead of a technician to determine whether each system is “OK” or
“NG”.
ECU PART NUMBER TCM part number can be read.
Item name Condition Display value
AT F T E M P S E 1
0°C (32° F) - 20°C (68°F) - 80°C (176°F)3.2 - 2.5 - 0.8 V
AT F T E M P S E 23.2 - 2.4 - 0.65 V
TCC SOLENOIDWhen perform slip lock-up 0.2 - 0.4 A
When perform lock-up 0.4 - 0.6 A
SLCT LVR POSISelector lever in “N”,“P” position. N/P
Selector lever in “R” position. R
Selector lever in “D” position. D
Selector lever in “4” position. 4
Selector lever in “3” position. 3
Selector lever in “2” position. 2
Selector lever in “1” position. 1
VHCL/S SE·A/T During driving Approximately matches the
speedometer reading.
ENGINE SPEED Engine running Closely matches the tachometer
reading.
LINE PRES SOL During driving 0.2 - 0.6 A
TURBINE REV During driving (lock-up ON) Approximately matches the
engine speed.
VHCL/S SE·MTR During driving Approximately matches the
speedometer reading.