2005 INFINITI QX4 relay

DTC P0615 START SIGNAL CIRCUIT
AT-101
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Revision: October 20052005 QX56
TCM terminals and data are reference value. Measured between each terminal and ground.
Diagnostic ProcedureECS00CF2
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 voltage between the IPDM E/R connector and ground.
OK or NG
OK >> GO TO 5.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN A/T ASSEMBLY HARNESS CONNECTOR AND IPDM E/R CONEC-
TOR.
1. Turn ignition switch OFF.
2. Disconnect A/T assembly harness connector and IPDM E/R
connector.
3. Check continuity between A/T assembly harness connector and
IPDM E/R connector.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
Terminal Wire color Item
ConditionData (Approx.)
9 B/R Starter relaySelector lever in "N" and "P" positions. Battery voltage
Selector lever in other positions. 0V
Item name Condition Display value
STARTER RELAYSelector lever in "N'', "P'' positions. ON
Selector lever in other positions. OFF
PCIA0056E
Item ConnectorTe r m i n a l
(Wirer color)Shift position Voltage (Approx.)
Starter
relayE12248
(B/R)Ground"N'' and "P'' Battery voltage
"R'' and "D'' 0V
LCIA0320E
Item ConnectorTerminal
(Wire color)Continuity
A/T assembly harness con-
nectorF9 9 (B/R)
Ye s
IPDM E/R connector E122 48 (B/R)
WCIA0427E

AT-102
DTC P0615 START SIGNAL CIRCUIT
Revision: October 20052005 QX56
3. CHECK TERMINAL CORD ASSEMBLY
1. Remove control valve with TCM. Refer to AT-231, "
Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
2. Disconnect A/T assembly harness connector and TCM connector.
3. Check continuity between A/T assembly harness connector ter-
minal and TCM connector terminal.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 4.
NG >> Replace open circuit or short to ground and short to power in harness or connectors.
4. 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)" .
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-231, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2"
NG >> Repair or replace damaged parts.
5. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-99, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item ConnectorTerminal (Wire
Color) Continuity
A/T assembly harness con-
nectorF9 9 (G)
Ye s
TCM connector F502 8 (G)
SCIA5440E

AT-180
TROUBLE DIAGNOSIS FOR SYMPTOMS
Revision: October 20052005 QX56
TCM terminals and data are reference value. Measured between each terminal and ground.
A/T CHECK Indicator Lamp Does Not Come OnECS00CK3
SYMPTOM:
AT CHECK indicator lamp does not come on for about 2 seconds when turning ignition switch to
“ON”.
DIAGNOSTIC PROCEDURE
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT-85, "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT-95, "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK A/T CHECK INDICATOR LAMP CIRCUIT
Check the combination meter. Refer to DI-5, "
COMBINATION METERS" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 8 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >>INSPECTION END
NG >> Repair or replace damaged parts.
Engine Cannot Be Started In “P” or “N” PositionECS00CK4
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- 8 5 , "
SELF-DIAGNOSTIC RESULT MODE" .
Do the self-diagnosis results indicate PNP switch?
YES >> Check the malfunctioning system. Refer to AT-104, "DTC P0705 PARK/NEUTRAL POSITION
SWITCH" .
NO >> GO TO 2.
Te r m i n a lWire
colorItem
ConditionData (Approx.)
3 L CAN-H – –
4VK-line (CONSULT-
II signal)The terminal is connected to the data link connector for CONSULT-II –
7 R Back-up lamp relaySelector lever in "R" position. 0V
Selector lever in other positions. Battery voltage
8 P CAN-L – –

ATC-18
REFRIGERATION SYSTEM
Revision: October 20052005 QX56
REFRIGERATION SYSTEMPFP:KA990
Refrigerant CycleEJS003X1
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 ProtectionEJS003X2
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 de-energizes 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).

AIR CONDITIONER CONTROL
ATC-25
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Revision: October 20052005 QX56
MAGNET CLUTCH CONTROL
When A/C switch or DEF switch is pressed, front air control inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant pressure sen-
sor signal, throttle angle sensor, etc.). If it judges compressor can be turned ON, it sends compressor ON sig-
nal to IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate com-
pressor.
SELF-DIAGNOSTIC SYSTEM
The self-diagnostic system is built into the front air control to quickly locate the cause of symptoms. Refer to
ATC-55, "
A/C System Self-diagnosis Function"
WJIA1163E

ATC-96
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
1. CHECK FUSES
Check 20A fuses [No. 24 and 27 (Located in the fuse and fusible link box)]. For fuse layout. Refer to PG-77,
"FUSE AND FUSIBLE LINK BOX" .
OK or NG
OK >> GO TO 2.
NG >> GO TO 10.
2. CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front blower motor connector.
3. Turn ignition switch ON.
4. Press the mode switch to select any mode except off.
5. Turn the front blower control dial to high.
6. Check voltage between front blower motor harness connector
M62 terminal 2 (W/L) and ground.
OK or NG
OK >> GO TO 12.
NG >> GO TO 3.
3. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect front blower motor relay.
3. Turn ignition switch ON.
4. Check voltage between front blower motor relay harness con-
nector M107 terminals 5 (G/R) and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
4. CHECK FRONT BLOWER MOTOR RELAY
Turn ignition switch OFF.
Refer to ATC-100, "
Front Blower Motor Relay" .
OK or NG
OK >> GO TO 5.
NG >> Replace front blower motor relay.Fuses are good.
2 - Ground : Battery voltage.
WJIA1331E
5 - Ground : Battery voltage.
WJIA1359E

TROUBLE DIAGNOSIS
ATC-97
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Revision: October 20052005 QX56
5. CHECK FRONT BLOWER MOTOR RELAY (SWITCH SIDE) CIRCUIT FOR OPEN
Check continuity between front blower motor relay harness connec-
tor M107 terminal 3 (W/L) and front blower motor harness connector
M62 terminal 2 (W/L).
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK VARIABLE BLOWER CONTROL POWER SUPPLY CIRCUIT FOR OPEN
1. Disconnect variable blower control harness connector.
2. Check continuity between front blower motor relay harness con-
nector M107 terminals 3 (W/L) and variable blower control har-
ness connector M122 terminal 1 (W/L).
OK or NG
OK >> GO TO 7.
NG >> Repair harness or connector.
7. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT
1. Disconnect front air control connector.
2. Check continuity between front air control harness connector
M49 terminal 13 (G/R) and variable blower control harness con-
nector M122 terminal 2 (G/R).
OK or NG
OK >> GO TO 8.
NG >> Repair harness or connector.
8. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) POWER SUPPLY
1. Turn ignition switch ON.
2. Check voltage between front blower motor relay harness con-
nector M107 terminal 2 (Y/G) and ground.
OK or NG
OK >> GO TO 9.
NG >> Repair harness or connector.3 - 2 : Continuity should exist.
WJIA1360E
3 - 1 : Continuity should exist.
WJIA1361E
13 - 2 : Continuity should exist.
WJIA1362E
2 - Ground : Battery voltage.
WJIA1363E

ATC-98
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
9. CHECK FRONT BLOWER MOTOR RELAY (COIL SIDE) GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between front blower motor relay connector
M107 terminal 1 (R/B) and front air control harness connector
M49 terminal 26 (R/B).
OK or NG
OK >> Replace front air control. Refer to ATC-147, "FRONT
AIR CONTROL" .
NG >> Repair harness or connector.
10. REPLACE FUSES
1. Replace fuses.
2. Activate the front blower motor.
3. Do fuses blow?
YES or NO
YES >> GO TO 11.
NO >> Inspection End.
11 . CHECK FRONT BLOWER MOTOR POWER SUPPLY CIRCUIT FOR SHORT
1. Turn ignition switch OFF.
2. Disconnect front blower motor connector and variable blower
control connector.
3. Check continuity between variable blower control harness con-
nector M122 terminal 1 (W/L) and ground.
OK or NG
OK >> GO TO 12.
NG >> Repair harness or connector.
12. CHECK VARIABLE BLOWER CONTROL SIGNAL CIRCUIT
1. Disconnect front air control connector.
2. Check continuity between front air control harness connector
M49 terminal 13 (G/R) and variable blower control harness con-
nector M122 terminal 2 (G/R).
OK or NG
OK >> GO TO 13.
NG >> Repair harness or connector.
13. CHECK FRONT BLOWER MOTOR
Refer to ATC-100, "
Front Blower Motor" .
OK or NG
OK >> GO TO 14.
NG >> Replace front blower motor.1 - 26 : Continuity should exist.
WJIA1364E
1 - Ground. : Continuity should not exist.
WJIA1365E
13 - 2 : Continuity should exist.
WJIA1366E