Combination INFINITI QX56 2004 Factory User Guide

TROUBLE DIAGNOSIS
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TROUBLE DIAGNOSISPFP:00004
DTC Inspection Priority ChartUCS002C R
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority
chart.
NOTE:
If DTC U1000 is displayed with other DTCs, first perform the trouble diagnosis for DTC U1000. Refer to
AT-1 03
.
Fail-SafeUCS002CS
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is a an error in
a main electronic control input/output signal circuit. In fail-safe mode the transmission is fixed in 2nd or 4th
(depending on the breakdown position), so the customer should feel “slipping” or “poor acceleration”. When
fail-safe mode is triggered, when the ignition switch is switched “ON”, the AT CHECK indicator lamp flashes for
about 8 seconds.
Even when the electronic circuits are normal, under special conditions (for example, when slamming on the
brake with the wheels spinning drastically and stopping the tire rotation), the transmission can go into fail-safe
mode. If this happens, switch “OFF” the ignition switch for 10 seconds, then switch it “ON” again to return to
the normal shift pattern. Also, the AT CHECK indicator lamp flashes for about 8 seconds once, then is cleared.
Therefore, the customer's vehicle has returned to normal, so handle according to the “diagnostics flow” (Refer
to AT-46, "
WORK FLOW" ).
FAI L-S AFE FUN CT ION
If any malfunction occurs in a sensor or solenoid, this function controls the A/T to mark driving possible.
Vehicle Speed Sensor

Signals are input from two systems - from vehicle speed sensor A/T (revolution sensor) installed on the
transmission and from combination meter so normal driving is possible even if there is a malfunction in
one of the systems. And if vehicle speed sensor A/T (revolution sensor) has unusual cases, 5th gear is
prohibited.
Accelerator Pedal Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the engine speed is fixed by ECM to a pre-determined engine speed to make driving possible.
Throttle Position Sensor

If there is a malfunction in one of the systems, the accelerator opening angle is controlled by ECM accord-
ing to a pre-determined accelerator angle to make driving possible. And if there are malfunctions in tow
systems, the accelerator opening angle is controlled by the idle signal sent from the ECM which is based
on input indicating either idle condition or off-idle condition (pre-determined accelerator opening) in order
to make driving possible.
PNP Switch

In the unlikely event that a malfunction signal enters the TCM, the position indicator is switched “OFF”, the
starter relay is switched “OFF” (starter starting is disabled), the back-up lamp relay switched “OFF” (back-
up lamp is OFF) and the position is fixed to the “D” range to make driving possible.
Starter Relay

The starter relay is switched “OFF”. (Starter starting is disabled.)
Priority Detected items (DTC)
1 U1000 CAN communication line
2 Except above

AT-136
DTC P1721 VEHICLE SPEED SENSOR MTR
Revision: August 20072004 QX56
DTC P1721 VEHICLE SPEED SENSOR MTRPFP:24814
DescriptionUCS002FI
The vehicle speed sensor·MTR signal is transmitted from combination meter to TCM by CAN communication
line. The signal functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM
will then use the vehicle speed sensor·MTR signal.
CONSULT-II Reference ValueUCS002FJ
On Board Diagnosis LogicUCS002FK

This is not an OBD-II self-diagnostic item.

Diagnostic trouble code “VHE SPD SE·MTR” with CONSULT-II is detected when TCM does not receive
the proper vehicle speed sensor MTR signal (input by CAN communication) from combination meter.
Possible CauseUCS002FL
Harness or connectors
(The sensor circuit is open or shorted.)
DTC Confirmation ProcedureUCS002FM
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “A/T” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
ACCELE POS: 1/8 or less
VHCL SPEED SE: 30 km/h (17 MPH) or more
4. If DTC is detected, go to AT-137, "
Diagnostic Procedure" .
Item name Condition Display value (Approx.) (km/h)
VHCL/S SE·MTR During driving Approximately matches the speedometer reading.
BCIA0030E

DTC P1721 VEHICLE SPEED SENSOR MTR
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Diagnostic ProcedureUCS002FN
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer AT-93, "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Drive vehicle and read out the value of “VHCL/S SE·MTR”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. CHECK COMBINATION METER
Check combination meter. Refer to DI-17, "
How to Proceed With Trouble Diagnosis"
OK or NG
OK >> GO TO 8.
NG >> Repair or replace damaged parts.
4. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 5.
NG >> GO TO 7.
5. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 1 3 6 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 6.
6. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
Item name Condition Display value (km/h)
VHCL/S SE·MTR During driving Approximately matches the
speedometer reading.
SCIA2148E

AT-188
BRAKE SIGNAL CIRCUIT
Revision: August 20072004 QX56
BRAKE SIGNAL CIRCUITPFP:25320
CONSULT-II Reference ValueUCS002IE
Diagnostic ProcedureUCS002IF
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT-93, "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT-103, "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK STOP LAMP SWITCH CIRCUIT
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Read out ON/OFF switching action of the “BRAKE SW”.
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. CHECK STOP LAMP SWITCH
Check continuity between stop lamp switch harness connector termi-
nals 3 and 4.
Check stop lamp switch after adjusting brake pedal — refer to
BR-6, "
BRAKE PEDAL" .
OK or NG
OK >>INSPECTION END
NG >> Check the following items. If NG, repair or replace dam-
aged parts.

Harness for short or open between battery and stop lamp switch.

Harness for short or open between stop lamp switch and combination meter.
Item name Condition Display value
BRAKE SWDepressed brake pedal. ON
Released brake pedal. OFF
PCIA0070E
Condition Continuity
When brake pedal is depressed Yes
When brake pedal is released No
SCIA2126E

TOW MODE SWITCH
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Revision: August 20072004 QX56
TOW MODE SWITCHPFP:25129
DescriptionUCS002IG
When tow mode switch is “ON”, tow mode switch signals are sent to TCM from combination meter by CAN
communication line.Then it`s a tow mode condition.
Diagnostic ProcedureUCS002IH
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT - 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is any malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK POWER SOURCE
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check the voltage between tow mode switch connector terminal
1 and ground.
OK or NG
OK >>INSPECTION END
NG >> GO TO 3.
3. CHECK TOW MODE SWITCH
1. Turn ignition switch “OFF”.
2. Disconnect tow mode switch connector.
3. Check continuity between tow mode switch connector M254 ter-
minals 1 and 2.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace tow mode switch.
4. DETECT MALFUNCTIONING ITEM
Check the following items. If any items are damaged, repair or replace damaged parts.

Harness for short or open between combination meter connector terminal 35 and tow mode switch con-
nector terminal 1.

Harness for short or open between tow mode switch connector terminal 2 and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
ConditionTo w m o d e
switchData (Approx.)
When ignition switch is turned to “ON”ON 0V
OFF Battery voltage
SCIA5156E
Condition Continuity
To w m o d e s w i t c h “ O N ” Ye s
To w m o d e s w i t c h “ O F F ” N o
SCIA5157E

AT-190
TOW MODE SWITCH
Revision: August 20072004 QX56
5. CHECK COMBINATION METER
Check the combination meter. Refer to DI-17, "
How to Proceed With Trouble Diagnosis" .
OK or NG
OK >>INSPECTION END
NO >> Repair or replace damaged parts.

AT-192
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: August 20072004 QX56
4. CHECK TCM GROUND CIRCUIT
1. Turn ignition switch “OFF”.
2. Disconnect the A/T assembly harness connector.
3. Check the continuity between A/T assembly harness connector
(vehicle side) 5 (B), 10 (B) and ground. Refer to AT - 5 2 , "
Wiring
Diagram — AT —" .
4. If OK, check the harness for short-circuit to ground or the power
source.
OK or NG
OK >> GO TO 5.
NG >> Repair the open or short circuit in the harness or con-
nector.
5. CHECK AT CHECK INDICATOR LAMP CIRCUIT
1. Turn ignition switch “OFF”.
2. Check the combination meter.
Refer to DI-17, "
How to Proceed With Trouble Diagnosis" .
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Engine Cannot Be Started In “P” or “N” PositionUCS002IJ
SYMPTOM:

Engine cannot be started with selector lever in “P” or “N” position.

Engine can be started with selector lever in “D”or “R” position.
DIAGNOSTIC PROCEDURE
1. CHECK SELF-DIAGNOSIS RESULTS
Perform self-diagnosis. Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnosis results indicate PNP switch?
YES >> Check the malfunctioning system. Refer to AT-109, "DTC P0705 PARK/NEUTRAL POSITION
SWITCH" .
NO >> GO TO 2.
2. CHECK CONTROL CABLE
Check the control cable.

Refer to AT-234, "Checking of A/T Position" .
OK or NG
OK >> GO TO 3.
NG >> Adjust control cable. Refer to AT-234, "
Adjustment of A/
T Position" .
SCIA2106E
LCIA0324E

NAVIGATION SYSTEM
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Terminals and Reference Value for BCMEKS007LS
Terminal
No.Wire
colorSignal nameMeasuring condition
Reference value
(Approx.) Ignition
switchOperation or condition
2 SB Combination switch input 5 ONLighting, turn, wiper OFF
Wiper dial position 4
3 G/Y Combination switch input 4 ONLighting, turn, wiper OFF
Wiper dial position 4
4 Y Combination switch input 3 ONLighting, turn, wiper OFF
Wiper dial position 4
5 G/B Combination switch input 2
ONLighting, turn, wiper OFF
Wiper dial position 4
6 V Combination switch input 1
11 O Ignition switch ACC ACC — Battery voltage
32 R/G Combination switch output 5 ONLighting, turn, wiper OFF
Wiper dial position 4
33 R/Y Combination switch output 4 ONLighting, turn, wiper OFF
Wiper dial position 4
34 L Combination switch output 3 ONLighting, turn, wiper OFF
Wiper dial position 4
SKIA5291E
SKIA5292E
SKIA5291E
SKIA5292E
SKIA5291E
SKIA5292E
SKIA5291E

AV-100
NAVIGATION SYSTEM
Revision: August 20072004 QX56
35 O/B Combination switch output 2
ONLighting, turn, wiper OFF
Wiper dial position 4
36 R/W Combination switch output 1
38 W/L Ignition switch (ON) ON — Battery voltage
39 W CAN− H—— —
40 R CAN− L—— —
57 Y/R Battery power supply OFF — Battery voltage
67 B Ground ON — 0V
70 W/B Battery power supply (fusible link) OFF — Battery voltage Terminal
No.Wire
colorSignal nameMeasuring condition
Reference value
(Approx.) Ignition
switchOperation or condition
SKIA5292E

NAVIGATION SYSTEM
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Revision: August 20072004 QX56
Vehicle Speed Signal Check for NAVI Control UnitEKS007M3
1. CHECK HARNESS
1. Turn ignition switch OFF.
2. Disconnect NAVI control unit connector, combination meter connector, display control unit connector and
shift lock control unit connector.
3. Check continuity between NAVI control unit harness connector
B152 terminal 28 (W/R) and combination meter harness con-
nector M24 terminal 29 (W/R).
4. Check continuity between NAVI control unit harness connector
B152 terminal 28 (W/R) and ground.
OK or NG
OK >> GO TO 2.
NG >> Repair harness.
2. CHECK 1: VEHICLE SPEED SIGNAL
1. Connect NAVI control unit connector.
2. Turn ignition switch ON.
3. Check voltage between NAVI control unit harness connector
B152 terminal 28 (W/R) and ground.
OK or NG
OK >> GO TO 3.
NG >> Replace NAVI control unit. Refer to AV-157, "
Removal
and Installation of NAVI Control Unit" .
3. CHECK 2: VEHICLE SPEED SIGNAL
1. Connect combination meter connector, display control unit connector and shift lock control unit connector.
2. Drive vehicle at a constant speed.
3. Check signal between NAVI control unit harness connector
B152 terminal 28 (W/R) and ground with CONSULT-ll or oscillo-
scope.
OK or NG
OK >> Replace NAVI control unit. Refer to AV-157, "Removal
and Installation of NAVI Control Unit" .
NG >> Check combination meter system. Refer to DI-19, "
Veh i-
cle Speed Signal Inspection" . Continuity should exist.
Continuity should not exist.
WKIA1769E
Approx. 3.5V or more
SKIA4295E
28 (W/R) – Ground : Refer to AV-90, "Terminals
and Reference Value for NAVI
Control unit" .
SKIA4615E