Relay INFINITI QX56 2004 Factory User Guide

A/T CONTROL SYSTEM
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Revision: August 20072004 QX56
TCM FunctionUCS002CE
The function of the TCM is to:

Receive input signals sent from various switches and sensors.

Determine required line pressure, shifting point, lock-up operation, and engine brake operation.

Send required output signals to the respective solenoids.
CONTROL SYSTEM OUTLINE
The automatic transmission senses vehicle operating conditions through various sensors or signals. It always
controls the optimum shift position and reduces shifting and lock-up shocks.
CONTROL SYSTEM DIAGRAM
SENSORS (or SIGNALS)


TCM


ACTUATORS
PNP switch
Accelerator pedal position sensor
Closed throttle position signal
Wide open throttle position signal
Engine speed signal
A/T fluid temperature sensor
Revolution sensor
Vehicle speed signal
Stop lamp switch signal
Turbine revolution sensor
1st position switch signal
4th position switch signalShift control
Line pressure control
Lock-up control
Engine brake control
Timing control
Fail-safe control
Self-diagnosis
CONSULT-II communication line
Duet-EA control
CAN systemInput clutch solenoid valve
Direct clutch solenoid valve
Front brake solenoid valve
High and low reverse clutch
solenoid valve
Low coast brake solenoid valve
Torque converter clutch solenoid
valve
Line pressure solenoid valve
A/T CHECK indicator lamp
Sta rte r re lay
Back-up lamp relay
LCIA0317E

TROUBLE DIAGNOSIS
AT-43
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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

TROUBLE DIAGNOSIS
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TCM TERMINAL MEASUREMENT CHART
TCM terminals and data are reference value. Measured between each terminal and ground.
Te r m i n a l
No.Wire
colorItem Condition Data (Approx.)
1PPower supply
(Memory back-up)– Battery voltage
2PPower supply
(Memory back-up)– Battery voltage
3 W CAN-H – –
4VK-line (CONSULT-
II signal)The terminal is connected to the data link connector for CONSULT-II. –
5 B Ground – –
6Y/RPower supply– Battery voltage
–0V
7RBack-up lamp
relaySelector lever in “R” position. 0V
Selector lever in other positions. Battery voltage
8 R CAN-L – –
9 B/R Starter relaySelector lever in “N”,“ P” positions. Battery voltage
Selector lever in other positions. 0V
10 B Ground – –

AT-90
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
TCM Input/Output Signal Reference ValuesUCS002D7
A/T ASSEMBLY TERMINAL CONNECTOR LAYOUT
TCM INSPECTION TABLE
Data are reference value and are measured between each terminal and ground.
SCIA1658E
Terminal
No.Wire
colorItem Condition Data (Approx.)
1PPower supply
(Memory back-up)– Battery voltage
2PPower supply
(Memory back-up)– Battery voltage
3 W CAN-H – –
4VK-line (CONSULT-
II signal)The terminal is connected to the data link connector for CONSULT-II. –
5 B Ground – –
6Y/RPower supply– Battery voltage
–0V
7RBack-up lamp
relaySelector lever in “R” position. 0V
Selector lever in other positions. Battery voltage
8 R CAN-L – –
9 B/R Starter relaySelector lever in “N”,“ P” positions. Battery voltage
Selector lever in other positions. 0V
10 B Ground – –

AT-92
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
ATF PRES SW 1Front brake engaged. Refer to AT- 2 1ON
Front brake disengaged. Refer to AT- 2 1
OFF
ATF PRES SW 2Low coast brake engaged. Refer to AT-2 1
ON
Low coast brake disengaged. Refer to AT- 2 1
OFF
ATF PRES SW 3Input clutch engaged. Refer to AT- 2 1
ON
Input clutch disengaged. Refer to AT- 2 1
OFF
ATF PRES SW 5Direct clutch engaged. Refer to AT- 2 1
ON
Direct clutch disengaged. Refer to AT- 2 1
OFF
ATF PRES SW 6High and low reverse clutch engaged. Refer to AT- 2 1
ON
High and low reverse clutch disengaged. Refer to AT- 2 1
OFF
I/C SOLENOIDInput clutch disengaged. Refer to AT- 2 1
0.6 - 0.8 A
Input clutch engaged. Refer to AT- 2 1
0 - 0.05 A
FR/B SOLENOIDFront brake engaged. Refer to AT- 2 1
0.6 - 0.8 A
Front brake disengaged. Refer to AT- 2 1
0 - 0.05 A
D/C SOLENOIDDirect clutch disengaged. Refer to AT- 2 1
0.6 - 0.8 A
Direct clutch engaged. Refer to AT- 2 1
0 - 0.05 A
HLR/C SOLHigh and low reverse clutch disengaged. Refer to AT- 2 1
0.6 - 0.8 A
High and low reverse clutch engaged. Refer to AT- 2 1
0 - 0.05 A
ON OFF SOLLow coast brake engaged. Refer to AT-2 1
ON
Low coast brake disengaged. Refer to AT- 2 1
OFF
STARTER RELAYSelector lever in “N”,“P” position. ON
Selector lever in other position. OFF
ACCELE POSIReleased accelerator pedal. 0.0/8
Fully depressed accelerator pedal. 8/8
THROTTLE POSIReleased accelerator pedal. 0.0/8
Fully depressed accelerator pedal. 8/8
CLSD THL POSReleased accelerator pedal. ON
Fully depressed accelerator pedal. OFF
W/O THL POSFully depressed accelerator pedal. ON
Released accelerator pedal. OFF
BRAKE SWDepressed brake pedal. ON
Released brake pedal. OFF Item name Condition Display value

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

TROUBLE DIAGNOSIS
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P POSI IND (ON-OFF display) — — X
R POSI IND (ON-OFF display) — — X
N POSI IND (ON-OFF display) — — X
D POSI IND (ON-OFF display) — — X
4TH POSI IND (ON-OFF display) — — X
3RD POSI IND (ON-OFF display) — — X
2ND POSI IND (ON-OFF display) — — X
1ST POSI IND (ON-OFF display) — — X
MANU MODE IND (ON-OFF display) — — X
Not mounted but displayed.
POWER M LAMP (ON-OFF display) — — X
F-SAFE IND/L (ON-OFF display) — — X
ATF WARN LAMP (ON-OFF display) — — X
BACK-UP LAMP (ON-OFF display) — — X
STARTER RELAY (ON-OFF display) — — X
PNP SW3 MON (ON-OFF display) — — X
C/V CLB ID1 — — X
C/V CLB ID2 — — X
C/V CLB ID3 — — X
UNIT CLB ID1 — — X
UNIT CLB ID2 — — X
UNIT CLB ID3 — — X
TRGT GR RATIO — — X
TRGT PRES TCC (kPa) — — X
TRGT PRES L/P (kPa) — — X
TRGT PRES I/C (kPa) — — X
TRGT PRE FR/B (kPa) — — X
TRGT PRES D/C (kPa) — — X
TRG PRE HLR/C (kPa) — — X
SHIFT PATTERN — — X
DRV CST JUDGE — — X
START RLY MON — — X
NEXT GR POSI — — X
SHIFT MODE — — X
MANU GR POSI — — X
VEHICLE SPEED (km/h) — X X Vehicle speed recognized by the TCM.
Voltage (V) — — XDisplays the value measured by the voltage
probe.
Frequency (Hz) — — X
The value measured by the pulse probe is dis-
played. DUTY-HI (high) (%) — — X
DUTY-LOW (low) (%) — — X
PLS WIDTH-HI (ms) — — X
PLS WIDTH-LOW (ms) — — XMonitored item (Unit)Monitor Item Selection
Remarks ECU
INPUT
SIGNALSMAIN SIG-
NALSSELEC-
TION
FROM
MENU

DTC P0615 START SIGNAL CIRCUIT
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DTC P0615 START SIGNAL CIRCUITPFP:25230
DescriptionUCS002DE

TCM controls park/neutral (PNP) relay (starter relay) in IPDM E/R.

TCM switches PNP relay “ON” at “P” or “N” position and allows to crank engine.

Then it prohibits cranking other than at “P” or “N” position.
CONSULT-II Reference ValueUCS002DF
On Board Diagnosis LogicUCS002DG

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

Diagnostic trouble code “STARTER RELAY/CIRC” with CONSULT-II is detected when detects as irregular
when park/neutral (PNP) relay (starter relay) is switched “ON” other than at “P” or “N” position. (Or when
switched “OFF” at “P” or “N” position).
Possible CauseUCS002D H

Harness or connectors
[The park/neutral position (PNP) relay (starter relay) and TCM circuit is open or shorted.]

Park/neutral position (PNP) relay (starter relay)
DTC Confirmation ProcedureUCS002DI
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.
4. Drive vehicle for at least 2 consecutive seconds.
5. If DTC is detected, go to AT - 1 0 6 , "
Diagnostic Procedure" .
Item name Condition Display value
STARTER RELAYSelector lever in “N”,“P” position. ON
Selector lever in other position. OFF
BCIA0030E

AT-106
DTC P0615 START SIGNAL CIRCUIT
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002DJ
1. CHECK STARTER RELAY
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II and check monitor “STARTER
RELAY” ON/OFF.
Without CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Check the voltage between the IPDM E/R connector and
ground.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. DETECT MALFUNCTIONING ITEM
Check the following items:

Starter relay, Refer to SC-10, "STARTING SYSTEM" .

IPDM E/R, Refer to PG-17, "IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE
ROOM)" .

Disconnections or short-circuits in the harness between TCM and IPDM E/R.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
Item name Condition Display value
STARTER RELAYSelector lever in N, P position. ON
Selector lever in other position. OFF
PCIA0056E
Item ConnectorTe r m i n a l
(Wirer color)Shift position Voltage (Approx.)
Sta rte r
relayE12248
(B/R)GroundN and P Battery voltage
R, D and M 0V
LCIA0320E

ATC-18
REFRIGERATION SYSTEM
Revision: August 20072004 QX56
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleEJS002BS
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the front and rear evaporators, and back to the compressor. The refrigerant evaporation through the
evaporator coils are controlled by front and rear externally equalized expansion valves, located inside the front
and rear evaporator cases.
Refrigerant System ProtectionEJS002BT
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM.
The ECM deenergizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressure sensor is over about 2,746 kPa (28 kg/cm
2 , 398 psi), or below
about 120 kPa (1.22 kg/cm
2 , 17.4 psi).