Nissan Murano Z50 (2005 year). Manual - part 7

TROUBLE DIAGNOSIS

ATC-73

ATC

Revision: 2005 August

2005 Murano

COMPONENT DESCRIPTION
Intake Door Motor

The intake door motor is attached to the intake unit. It rotates so that
air is drawn from inlets set by the unified meter and A/C amp. Motor
rotation is conveyed to a lever which activates the intake door.

DIAGNOSIS PROCEDURE FOR INTAKE DOOR MOTOR

SYMPTOM: Intake door motor does not operate normally.
Perform diagnosis procedure. Refer to

ATC-61, "DIAGNOSIS PROCEDURE FOR LAN CIRCUIT"

RJIA1788E

ATC-74

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

Blower Motor Circuit

AJS001F4

SYMPTOM: Blower motor operation is malfunctioning.

INSPECTION FLOW

ATC-56, "Operational Check"

ATC-106, "Intake Sensor Circuit"

ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 4.

ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 6.

ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 13.

ATC-76, "DIAGNOSIS PROCEDURE
FOR BLOWER MOTOR"

ATC-37, "SYMPTOM TABLE"

ATC-97, "Ambient Sensor Circuit"

ATC-100, "In-vehicle Sensor Circuit"

*10

ATC-103, "Sunload Sensor Circuit"

*11

EC-205, "DTC P0117, P0118 ECT
SENSOR"

RJIA1789E

TROUBLE DIAGNOSIS

ATC-75

ATC

Revision: 2005 August

2005 Murano

SYSTEM DESCRIPTION
Component Parts

Fan speed control system components are:

●

Unified meter and A/C amp.

●

A/C LAN system (PBR built-in mode door motor, intake door motor and air mix door motor)

●

In-vehicle sensor

●

Ambient sensor

●

Sunload sensor

●

Intake sensor

System Operation

Automatic Mode

In the automatic mode, the blower motor speed is calculated by the unified meter and A/C amp. based on the
input from the PBR, in-vehicle sensor, sunload sensor, intake sensor and ambient sensor.
When the air flow is increased, the duty ratio of the blower fan motor’s drive signal is changed at 8%/sec. to
prevent a sudden increase in air flow.
In addition to manual air flow control and the usual automatic air flow control, starting air flow control, low
water temperature starting control and high passenger compartment temperature starting control are avail-
able.

Starting Fan Speed Control

Start up from COLD SOAK Condition (Automatic mode)
In a cold start up condition where the engine coolant temperature is below 56

C (133

F), the blower will not

operate for a short period of time (up to 150 seconds). The exact start delay time varies depending on the
ambient and engine coolant temperature.
In the most extreme case (very low ambient) the blower starting delay will be 150 seconds as described
above. After this delay, the blower will operate at low speed until the engine coolant temperature rises above
56

C (133

F), and then the blower speed will increase to the objective speed.

Start up from usual or HOT SOAK Condition (Automatic mode)
The blower will begin operation momentarily after the AUTO switch is pushed. The blower speed will gradually
rise to the objective speed over a time period of 3 seconds or less (actual time depends on the objective
blower speed).

SJIA0526E

ATC-76

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

Blower Speed Compensation

Sunload
When the in-vehicle temperature and the set temperature are very close, the blower will be operating at low
speed. The low speed will vary depending on the sunload. During conditions of low or no sunload, the blower
speed is at duty ratio 25%. During high sunload conditions, the unified meter and A/C amp. raise the blower
speed (duty ratio 49%).

Fan Speed Control Specification

COMPONENT DESCRIPTION
Brush-less Motor

The blower motor utilizes a brush-less motor with a rotating magnet.
Quietness is improved over previous motors where the brush was
the point of contact and the coil rotated.

DIAGNOSIS PROCEDURE FOR BLOWER MOTOR

SYMPTOM: Blower motor operation is malfunctioning.

RJIA1996E

ZHA152H

SJIA0266E

TROUBLE DIAGNOSIS

ATC-77

ATC

Revision: 2005 August

2005 Murano

CHECK POWER SUPPLY FOR BLOWER MOTOR

Disconnect blower motor connector.

Turn ignition switch ON.

Check voltage between blower motor harness connector M70
terminal 1 (W/L) and ground.

OK or NG

>> GO TO 2.

>> Check power supply circuit and 15 A fuses [Nos. 10 and

11, located in the fuse block (J/B)]. Refer to

PG-70,

"FUSE BLOCK - JUNCTION BOX (J/B)"

●

If fuse are OK, check harness for open circuit. Repair or replace if necessary.

●

If fuse are NG, replace fuse and check harness for short circuit. Repair or replace if necessary.

CHECK BLOWER MOTOR GROUND CIRCUIT

Turn ignition switch OFF.

Check continuity between blower motor harness connector M70
terminal 3 (B) and ground.

OK or NG

>> GO TO 3.

>> Repair harness or connector.

CHECK CIRCUIT CONTINUITY BETWEEN BLOWER MOTOR AND UNIFIED METER AND A/C AMP.

Disconnect unified meter and A/C amp. connector.

Check continuity between blower motor harness connector M70
terminal 2 (L/Y) and unified meter and A/C amp. harness con-
nector M51 terminal 53 (L/Y).

OK or NG

>> GO TO 4.

>> Repair harness or connector.

1 – Ground

: Battery voltage

RJIA1997E

3 – Ground

: Continuity should exist.

RJIA1998E

2 – 53

: Continuity should exist.

RJIA1999E

ATC-78

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

CHECK UNIFIED METER AND A/C AMP. OUTPUT SIGNAL

Reconnect blower motor connector and unified meter and A/C
amp. connector.

Turn ignition switch ON.

Change the fan speed from Lo to Hi, and check the duty ratios between blower motor harness connector
M70 terminal 2 (L/Y) and ground using an oscilloscope. Normal terminal 2 (L/Y) drive signal duty ratios
are shown in the table below.

OK or NG

>> Replace blower motor after confirming the fan air flow does not change.

>> Replace unified meter and A/C amp.

COMPONENT INSPECTION
Blower Motor

Confirm smooth rotation of the blower motor.

●

Ensure that there are no foreign particles inside the blower unit.

RJIA2000E

RJIA1792E

RJIA1793E

TROUBLE DIAGNOSIS

ATC-79

ATC

Revision: 2005 August

2005 Murano

Magnet Clutch Circuit

AJS000ZC

SYMPTOM: Magnet clutch does not engage.

INSPECTION FLOW

ATC-106, "Intake Sensor Circuit"

ATC-97, "Ambient Sensor Circuit"

ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 13.

ATC-80, "DIAGNOSIS PROCEDURE
FOR MAGNET CLUTCH"

ATC-90, "TROUBLE DIAGNOSIS
FOR UNUSUAL PRESSURE"

ATC-56, "Operational Check"

ATC-49, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 4 to 6.

ATC-37, "SYMPTOM TABLE"

RJIA1794E

ATC-80

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

SYSTEM DESCRIPTION

Unified meter and A/C amp. controls compressor operation by ambient temperature and signal from ECM.

Low Temperature Protection Control

Unified meter and A/C amp. will turn the compressor ON or OFF as determined by a signal detected by intake
sensor.
When intake air temperature is higher than 4

C (39

F), the compres-

sor turns ON. The compressor turns OFF when intake air tempera-
ture is lower than 2.5

C (37

F).

DIAGNOSIS PROCEDURE FOR MAGNET CLUTCH

SYMPTOM: Magnet clutch does not engage when A/C switch is ON.

CHECK INTAKE SENSOR CIRCUIT

Check intake sensor. Refer to

ATC-49, "FUNCTION CONFIRMATION PROCEDURE"

, see No. 11.

OK or NG

>> GO TO 2.

>> Malfunctioning intake sensor: Refer to

ATC-106, "Intake Sensor Circuit"

PERFORM AUTO ACTIVE TEST

Refer to

PG-23, "Auto Active Test"

Does the magnet clutch operate?

YES

●

WITH CONSULT-II

GO TO 5.

●

WITHOUT CONSULT-II

GO TO 6.

>> Check 10 A fuse (No. 79, located in IPDM E/R), and GO TO 3.

RHA094GD

SJIA1232E

TROUBLE DIAGNOSIS

ATC-81

ATC

Revision: 2005 August

2005 Murano

CHECK CIRCUIT CONTINUITY BETWEEN IPDM E/R AND COMPRESSOR

Turn ignition switch OFF.

Disconnect IPDM E/R connector and compressor (magnet
clutch) connector.

Check continuity between IPDM E/R harness connector E8 ter-
minal 33 (Y/B) and compressor harness connector F28 terminal
1 (Y/B).

OK or NG

>> GO TO 4.

>> Repair harness or connector.

CHECK MAGNET CLUTCH CIRCUIT

Check for operation sound when applying battery voltage direct cur-
rent to terminal.

OK or NG

>> 1. Replace IPDM E/R.

2. Go to self-diagnosis procedure

ATC-49, "FUNCTION

CONFIRMATION PROCEDURE"

and perform self-

diagnosis STEP-4. Confirm that magnet clutch opera-
tion usual.

>> 1. Replace magnet clutch. Refer to

ATC-136, "Removal

and Installation of Compressor Clutch"

2. Go to self-diagnosis procedure

ATC-49, "FUNCTION

CONFIRMATION PROCEDURE"

and perform self-diagnosis STEP-4. Confirm that magnet

clutch operation usual.

CHECK BCM INPUT (COMPRESSOR ON) SIGNAL

Check compressor ON/OFF signal. Refer to

ATC-35, "CONSULT-II

Function (BCM)"

OK or NG

>> GO TO 8.

>> GO TO 6.

CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.

Turn ignition switch OFF.

Disconnect BCM connector and unified meter and A/C amp.
connector.

Check continuity between BCM harness connector M34 terminal
27 (GR) and unified meter and A/C amp. harness connector
M51 terminal 42 (GR).

OK or NG

>> GO TO 7.

>> Repair harness or connector.

33 – 1

: Continuity should exist.

RJIA2004E

RJIA2005E

A/C SW ON

: AIR COND SW ON

A/C SW OFF

: AIR COND SW OFF

RJIA1111E

27 – 42

: Continuity should exist.

RJIA2006E

ATC-82

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (COMPRESSOR ON SIGNAL)

Reconnect BCM connector and unified meter and A/C amp.
connector.

Turn ignition switch ON.

Check voltage between unified meter and A/C amp. harness
connector M51 terminal 42 (GR) and ground.

OK or NG

>> GO TO 8.

NG-1

>> If the voltage is approx. 5 V when A/C switch is ON: Replace unified meter and A/C amp.

NG-2

>> If the voltage is approx. 0 V when A/C switch is OFF: Replace BCM.

CHECK REFRIGERANT PRESSURE SENSOR

WITH CONSULT-II

Start the engine.

Check voltage of refrigerant pressure sensor. Refer to

EC-142, "CONSULT-II Reference Value in Data

Monitor"

WITHOUT CONSULT-II

Start the engine.

Check voltage between ECM harness connector F101 terminal
70 (W) and ground.

OK or NG

●

WITH CONSULT-II

GO TO 9.

●

WITHOUT CONSULT-II

GO TO 10.

>> Refer to

EC-681, "REFRIGERANT PRESSURE SENSOR"

Terminals

Condition

Voltage

(+)

(–)

Unified meter and

A/C amp. connector

Terminal No.

(wire color)

M51

42 (GR)

Ground

A/C switch: ON
(Blower motor
operates.)

Approx. 0 V

OFF switch: ON
(A/C system:
OFF)

Approx. 5 V

RJIA2007E

Terminals

Condition

Voltage

(+)

(–)

ECM

connector

Terminal No.

(wire color)

F101

70 (W)

Ground

A/C switch: ON
(Blower motor
operates.)

Approx. 1.0 - 4.0 V

PBIB1188E

TROUBLE DIAGNOSIS

ATC-83

ATC

Revision: 2005 August

2005 Murano

CHECK BCM INPUT (FAN ON) SIGNAL

Check FAN ON/OFF signal. Refer to

ATC-35, "CONSULT-II Function

(BCM)"

OK or NG

>> GO TO 12.

>> GO TO 10.

10.

CHECK CIRCUIT CONTINUITY BETWEEN BCM AND UNIFIED METER AND A/C AMP.

Turn ignition switch OFF.

Disconnect BCM connector and unified meter and A/C amp.
connector.

Check continuity between BCM harness connector M34 terminal
28 (SB) and unified meter and A/C amp. harness connector M51
terminal 57 (SB).

OK or NG

>> GO TO 11.

>> Repair harness or connector.

11.

CHECK VOLTAGE FOR UNIFIED METER AND A/C AMP. (FAN ON SIGNAL)

Reconnect BCM connector and unified meter and A/C amp.
connector.

Turn ignition switch ON.

Check voltage between unified meter and A/C amp. harness
connector M51 terminal 57 (SB) and ground.

OK or NG

>> GO TO 12.

NG-1

>> If the voltage is approx. 5 V when blower motor is ON: Replace unified meter and A/C amp.

NG-2

>> If the voltage is approx. 0 V when blower motor is OFF: Replace BCM.

FAN CONTROL DIAL ON

: FAN ON SIG ON

FAN CONTROL DIAL OFF

: FAN ON SIG OFF

RJIA1111E

28 – 57

: Continuity should exist.

RJIA2009E

Terminals

Condition

Voltage

(+)

(–)

Unified meter

and A/C amp.

connector

Terminal No.

(wire color)

M51

57 (SB)

Ground

Fan control dial: ON
(Blower motor oper-
ates.)

Approx. 0 V

Fan control dial: OFF

Approx. 5 V

RJIA2010E

ATC-84

TROUBLE DIAGNOSIS

Revision: 2005 August

2005 Murano

12.

CHECK CAN COMMUNICATION

Check CAN communication. Refer to

BCS-15, "CAN Communication Inspection Using CONSULT-II (Self-

Diagnosis)"

●

BCM – ECM

●

ECM – IPDM E/R

●

ECM – Unified meter and A/C amp.

OK or NG

>> INSPECTION END

>> Repair or replace malfunctioning part(s).

COMPONENT INSPECTION
Refrigerant Pressure Sensor

The refrigerant pressure sensor is attached to the condenser.
Make sure that the A/C refrigerant pressure and the sensor output
voltage are within the specified range as shown in the A/C operating
condition figure. Refer to

EC-681, "REFRIGERANT PRESSURE

SENSOR"

RJIA1795E

RJIA2954E