2004 INFINITI QX56 ignition

ON BOARD DIAGNOSTIC (OBD) SYSTEM
AT-41
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56

1st trip freeze frame data

System readiness test (SRT) codes

Test values
HOW TO ERASE DTC (WITH CONSULT-II)

If a DTC is displayed for both ECM and TCM, it is necessary to be erased for both ECM and TCM.
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Turn CONSULT-II “ON” and touch “A/T”.
3. Touch “SELF-DIAG RESULTS”.
4. Touch “ERASE”. (The DTC in the TCM will be erased.) Then touch “BACK” twice.
5. Touch “ENGINE”.
6. Touch “SELF-DIAG RESULTS”.
7. Touch “ERASE”. (The DTC in the ECM will be erased.)
HOW TO ERASE DTC (WITH GST)
1. If the ignition switch stays “ON” after repair work, be sure to turn ignition switch “OFF” once. Wait at least
10 seconds and then turn it “ON” (engine stopped) again.
2. Select Mode 4 with the Generic Scan Tool (GST). For details refer to EC-116, "
Generic Scan Tool (GST)
Function" .
HOW TO ERASE DTC (NO TOOLS)
1. Disconnect battery for 24 hours.
2. Reconnect battery.
SCIA5334E

AT-42
ON BOARD DIAGNOSTIC (OBD) SYSTEM
Revision: August 20072004 QX56
Malfunction Indicator Lamp (MIL)UCS002CQ
DESCRIPTION
The MIL is located on the instrument panel.
1. The MIL will light up when the ignition switch is turned “ON” with-
out the engine running. This is a bulb check.

If the MIL does not light up, refer to DI-31, "WARNING LAMPS"
.
2. When the engine is started, the MIL should go off.
If the MIL remains on, the on board diagnostic system has
detected an engine system malfunction.
SEF 2 17 U

TROUBLE DIAGNOSIS
AT-43
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
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-62
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Check Before Engine is StartedUCS002CY
1. CHECK AT CHECK INDICATOR LAMP
1. Park vehicle on level surface.
2. Move selector lever to “P” position.
3. Turn ignition switch to “OFF” position and wait at least 10 seconds.
4. Turn ignition switch to “ON” position. (Do not start engine.)
Does AT CHECK indicator lamp light up for about 2 seconds?
YES >> GO TO 2.
NO >> Stop the road test and go to AT-191, "
AT CHECK Indicator Lamp Does Not Come On" .
2. CHECK AT CHECK INDICATOR LAMP
Does AT CHECK indicator lamp flash for about 8 seconds?
YES >> For TCM fail-safe mode, carry out self-diagnostics and record all NG items on the diagnostics
worksheet. Refer to AT - 9 3
.
NO >> 1. Turn ignition switch to “OFF” position.
2. Carry out the self-diagnostics and record all NG items on the diagnostics worksheet. Refer to
AT - 9 3
.
3. Go to AT- 6 2 , "
Check at Idle" .
Check at Idle UCS002CZ
1. CHECK STARTING THE ENGINE
1. Park vehicle on level surface.
2. Move selector lever to “P” or “N” position.
3. Turn ignition switch to “OFF” position.
4. Turn ignition switch to “START” position.
Does the engine start?
YES >> GO TO 2.
NO >> Stop the road test and go to AT-192, "
Engine Cannot Be Started In “P” or “N” Position" .
2. CHECK STARTING THE ENGINE
1. Turn ignition switch to “ON” position.
2. Move selector lever in “D”,“4”, “3”, “2”, “1” or “R” position.
3. Turn ignition switch to “START” position.
Does the engine start in either position?
YES >> Stop the road test and go to AT-192, "Engine Cannot Be Started In “P” or “N” Position" .
NO >> GO TO 3.
3. CHECK “P” POSITION FUNCTIONS
1. Move selector lever to “P” position.
2. Turn ignition switch to “OFF” position.
3. Release the parking brake.
4. Push the vehicle forward or backward.
5. Engage the parking brake.
When you push the vehicle with disengaging the parking brake, does it move?
YES >> Enter a check mark at “Vehicle moves when pushed in “P” position” on the diagnostics worksheet,
then continue the road test.
NO >> GO TO 4.

AT-88
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
60
OthersVehicle runs with
transmission in “N”
position.
Refer to AT-194, "In
“N” Position, Vehicle
Moves" .ON vehicle1. PNP switchAT- 1 0 9
2. Fluid level and stateAT-5 8
3. Control cable adjustmentAT- 2 3 4
4. Control valve with TCMAT- 2 4 1
OFF vehicle5. Input clutchAT- 2 9 5
6. Gear systemAT- 2 6 1
7. Direct clutchAT- 3 0 7
8. Reverse brakeAT- 2 7 3
9. Forward one- way clutch (Parts behind drum support is
impossible to perform inspection by disassembly. Refer to
AT-1 8
, AT- 1 9 .)AT- 2 7 3
10. Forward brake (Parts behind drum support is impossible
to perform inspection by disassembly. Refer to AT- 1 8
, AT- 1 9
.)AT- 2 7 3
61Engine does not start
in “N” or “P” position.
Refer to AT-192, "Engine Cannot Be
Started In “P” or “N”
Position" .ON vehicle1. Ignition switch and starterPG-4
, SC-
10
2. Control cable adjustmentAT- 2 3 4
3. PNP switchAT- 1 0 9
62Engine starts in posi-
tions other than “N” or
“P”.ON vehicle1. Ignition switch and starterPG-4
, SC-
10
2. Control cable adjustmentAT- 2 3 4
3. PNP switchAT- 1 0 9
63 Engine stall.ON vehicle1. Fluid level and stateAT-5 8
2. Engine speed signalAT - 11 5
3. Turbine revolution sensorAT- 1 3 4
4. Torque converter clutch solenoid valveAT - 11 8
5. CAN communication lineAT- 1 0 3
6. Control valve with TCMAT- 2 4 1
OFF vehicle 7. Torque converterAT- 2 7 3
64Engine stalls when
select lever shifted “N”
→ “D”, “R”.ON vehicle1. Fluid level and stateAT-5 8
2. Engine speed signalAT - 11 5
3. Turbine revolution sensorAT- 1 3 4
4. Torque converter clutch solenoid valveAT - 11 8
5. CAN communication lineAT- 1 0 3
6. Control valve with TCMAT- 2 4 1
OFF vehicle 7. Torque converterAT- 2 7 3
No. Items Symptom Condition Diagnostic ItemReference
page

TROUBLE DIAGNOSIS
AT-93
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
CONSULT-II SETTING PROCEDURE
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.

For details, refer to the separate “CONSULT-II Operations Man-
ual”.
1. Turn ignition switch “OFF”.
2. Connect CONSULT-II and CONSULT-II CONVERTER to data
link connector, which is located in instrument lower panel on
driver side.
3. Turn ignition switch “ON”. (Do not start engine.)
4. Touch “START (NISSAN BASED VHCL)”.
5. Touch “A/T”.
If “A/T” is not indicated, go to GI-39, "
CONSULT-II Data Link
Connector (DLC) Circuit" .
6. Perform each diagnostic test mode according to each service
procedure.
SELF-DIAGNOSTIC RESULT MODE
Operation Procedure
1. Perform “CONSULT-II SETTING PROCEDURE” Refer to AT-93, "CONSULT-II SETTING PROCEDURE"
.
2. Touch “SELF-DIAG RESULTS”.
Display shows malfunction experienced since the last erasing
operation.
BBIA0369E
BCIA0029E
BCIA0030E
BCIA0031E

AT-94
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Display Items List
X: Applicable, —: Not applicable
Items (CONSULT-II
screen terms)Malfunction is detected when...TCM self-
diagnosisOBD-II (DTC)
“A/T” with
CONSULT-IIMIL indicator
lamp*1,
“ENGINE” with
CONSULT-II or
GST
CAN COMM CIRCUIT

When a malfunction is detected in CAN communications U1000 U1000
STARTER RELAY/
CIRC

If this signal is ON other than in P or N position, this is judged to be a
malfunction.
(And if it is OFF in P or N position, this too is judged to be a malfunc-
tion.)P0615 —
TCM

TCM is malfunctioning. P0700 P0700
PNP SW/CIRC

PNP switch 1-4 signals input with impossible pattern

PNP switch 3 monitor terminal cut line

“P” position is detected from N position without any other position
being detected in between.P0705 P0705
VEH SPD SEN/CIR AT
(Revolution sensor)

Signal from vehicle speed sensor A/T (Revolution sensor) not input
due to cut line or the like

Unexpected signal input during running

After ignition switch is turned ON, unexpected signal input from vehicle
speed sensor MTR before the vehicle starts movingP0720 P0720
ENGINE SPEED SIG

TCM does not receive the CAN communication signal from the ECM. P0725 —
TCC SOLENOID/CIRC

Normal voltage not applied to solenoid due to cut line, short, or the like P0740 P0740
A/T TCC S/V FNCTN

A/T cannot perform lock-up even if electrical circuit is good.

TCM detects as irregular by comparing difference value with slip rota-
tion.P0744 P0744*2
L/PRESS SOL/CIRC

Normal voltage not applied to solenoid due to cut line, short, or the like

TCM detects as irregular by comparing target value with monitor value.P0745 P0745
TCM·RAM

TCM memory (RAM) is malfunctioning. P1702 —
TCM·ROM

TCM memory (ROM) is malfunctioning. P1703 —
TP SEN/CIRC A/T

TCM does not receive the proper accelerator pedal position signals
(input by CAN communication) from ECM.P1705 P1705
ATF TEMP SEN/CIRC

During running, the ATF temperature sensor signal voltage is exces-
sively high or lowP1710 P0710
TURBINE REV S/CIRC

TCM does not receive the proper voltage signal from the sensor.

TCM detects an irregularity only at position of 4th gear for turbine revo-
lution sensor 2.P1716 P1716
VEH SPD SE/CIR·MTR

Signal (CAN communication) from vehicle speed sensor MTR not input
due to cut line or the like

Unexpected signal input during runningP1721 —
A/T INTERLOCK

Except during shift change, the gear position and ATF pressure switch
states are monitored and comparative judgement made.P1730 P1730
A/T 1ST E/BRAKING

Each ATF pressure switch and solenoid current is monitored and if a
pattern is detected having engine braking 1st gear other than in the M1
position, a malfunction is detected.P1731 —
I/C SOLENOID/CIRC

Normal voltage not applied to solenoid due to functional malfunction,
cut line, short, or the like

TCM detects as irregular by comparing target value with monitor value.P1752 P1752

DTC U1000 CAN COMMUNICATION LINE
AT-103
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC U1000 CAN COMMUNICATION LINEPFP:23710
DescriptionUCS002D9
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent malfunction detection ability.
Many electronic control units are equipped onto a vehicle, and each control unit shares information and links
with other control units during operation (not independent). In CAN communication, control units are con-
nected with 2 communication lines (CAN H line, CAN L line) allowing a high rate of information transmission
with less wiring. Each control unit transmits/receives data but selectively reads required data only.
On Board Diagnosis LogicUCS002DA

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “CAN COMM CIRCUIT” with CONSULT-II or U1000 without CONSULT-II is
detected when TCM cannot communicate to other control units.
Possible CauseUCS002DB
Harness or connectors
(CAN communication line is open or shorted.)
DTC Confirmation ProcedureUCS002D C
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 “ENGINE” with CONSULT-II.
3. Start engine and wait for at least 6 seconds.
4. If DTC is detected, go to AT - 1 0 4 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II”.
BCIA0030E