Infiniti M45 (Y34). Manual — part 152

TROUBLE DIAGNOSIS

ATC-93

C

D

E

F

G

H

I

K

L

M

A

B

ATC

High-Pressure Side is Too Low and Low-Pressure Side is Too High

Both High- and Low-Pressure Sides are Too Low

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

High-pressure side is too low and
low-pressure side is too high.

High- and low-pressure sides
become equal soon after com-
pressor operation stops.

Compressor pressure opera-
tion is improper.

↓

Damaged inside compressor
packings.

Replace compressor.

No temperature difference
between high- and low-pres-
sure sides

Compressor pressure opera-
tion is improper.

↓

Damaged inside compressor
packings.

Replace compressor.

AC356A

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Both high- and low-pressure sides
are too low.

●

There is a big temperature
difference between receiver
drier outlet and inlet. Outlet
temperature is extremely
low.

●

Liquid tank inlet and expan-
sion valve are frosted.

Liquid tank inside is slightly
clogged.

●

Replace liquid tank.

●

Check lubricant for contami-
nation.

●

Temperature of expansion
valve inlet is extremely low
as compared with areas
near liquid tank.

●

Expansion valve inlet may
be frosted.

●

Temperature difference
occurs somewhere in high-
pressure side.

High-pressure pipe located
between receiver drier and
expansion valve is clogged.

●

Check and repair malfunc-
tioning parts.

●

Check lubricant for contami-
nation.

Expansion valve and liquid
tank are warm or only cool
when touched.

Low refrigerant charge

↓

Leaking fittings or components

Check refrigerant for leaks.
Refer to

ATC-147, "Checking

for Refrigerant Leaks"

.

There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted.

Expansion valve closes a little
compared with the specifica-
tion.

↓

1. Improper expansion valve

adjustment

2. Malfunctioning expansion

valve

3. Outlet and inlet may be

clogged.

●

Remove foreign particles by
using compressed air.

●

Check lubricant for contami-
nation.

An area of the low-pressure
pipe is colder than areas near
the evaporator outlet.

Low-pressure pipe is clogged
or crushed.

●

Check and repair malfunc-
tioning parts.

●

Check lubricant for contami-
nation.

Air flow volume is not enough
or is too low.

Evaporator is frozen.

●

Check intake sensor circuit.
Refer to

ATC-109, "Intake

Sensor Circuit"

.

●

Replace compressor.

AC353A

ATC-94

TROUBLE DIAGNOSIS

Low-Pressure Side Sometimes Becomes Negative

Low-Pressure Side Becomes Negative

DIAGNOSTIC PROCEDURE FOR INSUFFICIENT COOLING

SYMPTOM: Insufficient cooling

1.

CHECK POWER SUPPLY FOR ECV (ELECTRONIC CONTROL VALVE)

1.

Disconnect compressor (ECV) connector.

2.

Turn ignition switch ON.

3.

Check voltage between compressor (ECV) harness connector
F10 terminal 2 (P) and ground.

OK or NG

OK

>> GO TO 2.

NG

>> Check power supply circuit and 10A fuse [No. 2, located

in the fuse block (J/B) No. 1]. Refer to

PG-62, "FUSE

BLOCK - JUNCTION BOX (J/B) NO.1"

.

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Low-pressure side sometimes
becomes negative.

●

Air conditioning system
does not function and does
not cyclically cool the com-
partment air.

●

The system constantly func-
tions for a certain period of
time after compressor is
stopped and restarted.

Refrigerant does not dis-
charge cyclically.

↓

Moisture is frozen at expan-
sion valve outlet and inlet.

↓

Water is mixed with refriger-
ant.

●

Drain water from refrigerant
or replace refrigerant.

●

Replace liquid tank.

AC354A

Gauge indication

Refrigerant cycle

Probable cause

Corrective action

Low-pressure side becomes nega-
tive.

Liquid tank or front/rear side of
expansion valve's pipe is
frosted or dewed.

High-pressure side is closed
and refrigerant does not flow.

↓

Expansion valve or liquid tank
is frosted.

Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.

●

If water is the cause, initially
cooling is okay. Then the
water freezes causing a
blockage. Drain water from
refrigerant or replace refrig-
erant.

●

If due to foreign particles,
remove expansion valve
and remove the particles
with dry and compressed air
(not shop air).

●

If either of the above meth-
ods cannot correct the mal-
function, replace expansion
valve.

●

Replace liquid tank.

●

Check lubricant for contami-
nation.

AC362A

2 – Ground

: Battery voltage

RJIA3046E

TROUBLE DIAGNOSIS

ATC-95

C

D

E

F

G

H

I

K

L

M

A

B

ATC

2.

CHECK ECV CONTROL SIGNAL

1.

Turn ignition switch OFF.

2.

Reconnect compressor (ECV) connector.

3.

Turn ignition switch ON.

4.

Set in self-diagnosis STEP-42.Refer to

ATC-50, "FUNCTION

CONFIRMATION PROCEDURE"

.

5.

Confirm the auto amp. harness connector M120 terminal 23 (G)
duty ratio using an oscilloscope.

OK or NG

OK

>> Replace compressor.

NG

>> GO TO 3.

3.

CHECK CIRCUIT CONTINUITY BETWEEN ECV AND AUTO AMP.

1.

Turn ignition switch OFF.

2.

Disconnect compressor (ECV) harness connector F10 terminal
3 (G) and auto amp. harness connector M120 terminal 23 (G).

OK or NG

OK

>> GO TO 4.

NG

>> Repair harness or connector.

4.

CHECK ECV

Check continuity between compressor (ECV) connector F10 termi-
nal 2 and 3.

OK or NG

OK

>> Replace auto amp.

NG

>> Replace compressor.

RJIA1475E

3 – 23

: Continuity should exist.

RJIA3047E

2 – 3

: Continuity should exist.

RJIA3048E

ATC-96

TROUBLE DIAGNOSIS

Insufficient Heating

AJS000CG

SYMPTOM: Insufficient heating

INSPECTION FLOW

*1

ATC-57, "Operational Check"

.

*2

ATC-50, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 1.

*3

ATC-50, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 5.

*4

ATC-50, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 7.

*5

ATC-69, "Air Mix Door Motor Circuit"

. *6

ATC-50, "FUNCTION CONFIRMA-
TION PROCEDURE"

, see No. 14.

*7

ATC-62, "LAN System Circuit"

.

*8

ATC-75, "Blower Motor Circuit"

.

*9

Thermostat and water control valve

CO-25, "INSPECTION AFTER
REMOVAL"

.

*10

MA-12, "Changing Engine Coolant"

.

*11

CO-13, "CHECKING RADIATOR
CAP"

.

RJIA1306E