Onvehicle Inspection

1. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET

(a) This is a method in which trouble is located by using a manifold gauge set. Read the manifold gauge pressure when the following conditions are established. Test conditions:

• Temperature at the air inlet with the switch set at RECIRC is 30 to 35°C (86 to 95°F)

• Engine is running at 1500 rpm

• Blower sped control switch is in the "HI" position

• Temperature control dial is in the "COOL" position

• Doors fully open

(1) The refrigeration system functions normally. Gauge reading:

Low pressure side: 0.15 to 0.25 MPa (1.5 to 2.5 kgf/cm2, 21.3 to 35.6 psi) High pressure side: 1.37 to 1.57 MPa (14 to 16 kgf/cm2, 199 to 228 psi)

(2) Moisture present in refrigeration system.

Condition: Periodially cools and then fails to cool

Symptom

Probable cause

Diagnosis

Corrective Actions

During operation, pressure on low pressure side cycles between normal and vacuum.

Moisture in refrigeration system freezes at expansion valve orifice causing a temporary stop of cycle, however, when it melts, normal state is restored.

• Dryer in oversaturated state

• Moisture in refrigeration system freezes at expansion valve orifice and blocks circulation of refrigerant

1. Replace condenser

2. Remove moisture in cycle by repeatedly evacuating air

3. Supply a proper amount of new refrigerant

(3) Insufficient cooling

Condition : Cooling system does not function effectively.

Symptom

Probable cause

Diagnosis

Corrective Actions

• Pressure low on both low and high pressure sides

• Insufficient cooling performance

Gas leakage in refrigeration system

• Insufficient refrigerant

• Refrigerant leaking

1. Check for gas leakage and repair if necessary

2. Supply a proper amount of new refrigerant

3. If indicated pressure value is close to 0 when connected to the gauge, create the vacuum after inspecting and repairing the location of leak

(4) Poor circulation of refrigerant

Condition : Cooling system does not function effectively.

Symptom

Probable cause

Diagnosis

Corrective Actions

• Pressure low on both low and high pressure sides

• Frost on pipe from condenser to unit

Refrigerant flow obstructed by dirt in receiver

Receiver clogged

Replace condenser

(5) Refrigerant does not circulate.

Symptom

Probable cause

Diagnosis

Corrective Actions

• Vacuum indicated on low pressure side, very low pressure indicated on high pressure side

• Frost or condensation seen on piping on both sides of cooler condenser core or cooler expansion value

• Refrigerant flow obstructed by moisture or dirt in refrigeration system

• Refrigerant flow obstructed by gas leaked from expansion valve

Refrigerant does not circulate

1. Check expansion valve

2. Clean out dirt in expansion valve by blowing air

3. Replace condenser

4. Evaporate air and supply a proper amount of new refrigerant

5. For gas leakage from expansion valve, replace expansion valve

(6) Refrigerant overcharged or insufficient cooling of condenser

Condition: Cooling system does not function effrctively.

Symptom

Probable cause

Diagnosis

Corrective Actions

Pressure too high on both low and high pressure sides

• Unable to develop sufficient performance due to excessive use of refrigeration system

• Insufficient cooling of condenser

• Excessive refrigerant in cycle ^ too much refrigerant supplied

• Condenser cooling insufficient ^ condenser fins clogged at cooling fan

1. Clean condenser *1

2. Check cooling fan with cooling fan motor operated *2

3. If (*1) and (*2) are in normal state, check the amount of refrigerant and supply a proper amount of refrigerant

(7) Air present in refrigeration system

Condition : Cooling system does not functior

1 :-

NOTE: These gauge indications occur when the refrigeration system opens and /^az^è^ the refrigerant is charged without vacuum purging.

xkiL-"6 35v^y

I022122E13

Symptom

Probable cause

Diagnosis

Corrective Actions

• Pressure too high on both low and high pressure sides

• The low pressure piping too hot to touch

Air in system

• Air present in refrigeration system

• Insufficient vacuum purging

1. Check compressor oil to see if it is dirty or insufficient

2. Evacuate air and supply new refrigerant

(8) Expansion valve malfunction

Condition : Insufficient Cooling.

Symptom

Probable cause

Diagnosis

Corrective Actions

• Pressure too high on both low and high pressure sides

• Frost or a large amount of condensation on piping on low pressure side

Trouble in expansion valve

• Excessive refrigerant in low pressure piping

• Expansion valve opened too wide

Check expansion valve

(9) Defective compressor

Condition : Insufficient Cooling.

Symptom

Probable cause

Diagnosis

Corrective Actions

• Pressure too high on low pressure sides

• Pressure too low on high pressure sides

Internal leak in compressor

• Compression failure

• Leakage from damaged valve or broken sliding parts

Repair or replace compressor

Gauge readings (Reference)

Front Passenger Side Seat Heater Temperature Sensor Circuit

DESCRIPTION

Voltage is output from the A/C amplifier to the seat heater control sub-assembly. The voltage changes according to the resistance of the thermistor in the seat heater LH (cushion). The A/C amplifier reads changes in voltage to control the seat heater. The resistance of the thermistor in the seat heater LH (cushion) differs according to ambient temperature.

DTC No.

Detection Item

Trouble Area

B1464/64

Seat heater temperature sensor (Open or short) (Passenger side)

• Seat heater control sub-assembly

• Harness or connector between seat heater control sub-assembly and A/C amplifier

• A/C amplifier

WIRING DIAGRAM

Seat Heater Control Sub-Assembly

Seat Heater RH (Cushion)

TH

A

TDC-

A

11 X1

A/C Amplifier

TSHR

INSPECTION PROCEDURE

INSPECT AIR CONDITIONING AMPLIFIER

2002 Toyota Mr2 Amplifier

(a) Remove the A/C amplifier with connectors still connected.

(b) Turn the ignition switch on (IG).

(c) Measure the voltage and resistance according to the value( s) in the table below.

Voltage

Tester connection (Symbols)

Condition

Specified condition

D37-2 (SHR) - Body ground

Seat heater switch: ON

Below 1 V

D37-2 (SHR) - Body ground

Seat heater switch: OFF

10 to 14 V

Resistance

Tester connection (Symbols)

Condition

Specified condition

D38-11 (SG7) - Body ground

Always

Below 1 Q

REPLACE AIR CONDITIONING AMPLIFIER

CHECK HARNESS AND CONNECTOR (A/C AMPLIFIER - SEAT HEATER CONTROL SUBASSEMBLY)

Air Conditioning Amplifier Connector Wire Harness View:

(a) Disconnect the connector from A/C amplifier.

H TSHR SG7

H TSHR SG7

Seat Heater Control Sub-assembly Connector Wire Harness View:

TDC-TDC+

C129708E02

(b) Disconnect the connector from the seat heater subassembly.

(c) Measure the resistance according to the value(s) in the table below.

Resistance

C129708E02

Tester connection (Symbols)

Condition

Specified condition

D38-4 (TSHR) - P13-5 (TDC+)

Always

Below 1 Q

D38-11 (SG7) - P13-3 (TDC-)

Always

Below 1 Q

D37-2 (SHR) - P13-2 (TH)

Always

Below 1 Q

Tester connection (Symbols)

Condition

Specified condition

D38-4 (TSHR) - Body ground

Always

10 kQ or higher

D38-11 (SG7) - Body ground

Always

10 kQ or higher

D37-2 (SHR) - Body ground

Always

10 kQ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT SEAT HEATER RH (SEAT CUSHION)

® -n 1—.—.—1 rL

CM

0

0

H

I046368E02

(a) Disconnect the seat cushion heater.

(b) Heat the temperature sensor and thermostat with a light.

(c) Measure the resistance according to the value(s) in the table below.

Resistance

Terminal No.

Condition

Specified condition

A2 - A3

Ambient temperature (15 °C to 40 °C)

4 kQ to 15 kQ

If the resistance is not as specified, replace the seat cushion heater assembly.

REPLACE SEAT HEATER RH (SEAT CUSHION)

REPLACE SEAT HEATER CONTROL SUB-ASSEMBLY

B1497/97

BUS IC Communication Malfunction

DESCRIPTION

The air conditioning harness assembly connects the air conditioning amplifier and each servomotor. The A/C amplifier supplies power and sends operation instructions to each servomotor through the air conditioning harness assembly. Each servomotor sends the damper position information to the A/C amplifier.

DTC No.

Detection Item

Trouble Area

B1497/97

Communication line error or open

• Air conditioning harness assembly

• A/C amplifier

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT AIR CONDITIONING AMPLIFIER

(a) Remove the A/C amplifier with connectors still connected.

(b) Measure the voltage according to the value(s) in the table below.

Voltage

Tester Connection

Condition

Specified Condition

X1-2 (BUS G) - Body ground

Always

Below 1 V

REPLACE AIR CONDITIONING AMPLIFIER

REPLACE AIR CONDITIONING AMPLIFIER

INSPECT AIR CONDITIONING AMPLIFIER

Air Conditioning Amplifier Connector Wire Harness View:

Air Conditioning Amplifier Connector Wire Harness View:

B BUS BUS G

I046084E17

B BUS BUS G

I046084E17

(a) Remove the A/C amplifier with connectors still connected.

(b) Measure the voltage according to the value(s) in the table below.

Voltage

Tester Connection

Condition

Specified Condition

X1-4 (B BUS) - X1-2 (BUS G)

Ignition switch on (IG)

10 to 14 V

X1-4 (B BUS) - X1-2 (BUS G)

Ignition switch off

Below 1 V

REPLACE AIR CONDITIONING AMPLIFIER

REPLACE AIR CONDITIONING AMPLIFIER

REPLACE AIR CONDITIONING HARNESS ASSEMBLY

B1499/99

Multiplex Communication Circuit

DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

B1499/99

Open in multiplex communication circuit

•Multiplex communication system

INSPECTION PROCEDURE

CHECK DIAGNOSTIC TROUBLE CODE (DTC B1499/99)

Result

Result

Proceed to

DTC (B1499/99) is not output

A

DTC (B1499/99) is output

B

GO TO MULTIPLEX COMMUNICATION SYSTEM

SYSTEM OK

Blower Motor Circuit

DESCRIPTION

The blower motor is operated by signals from the A/C amplifier. Blower motor speed signals are transmitted by changes in the duty ratio. Duty Ratio:

The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, B is the period of non-continuity. The blower motor controller controls the blower motor speed.

Blower Level

HI M2

M1 LO

HI M2

M1 LO

0 30 43 67 100 SI Duty (%)

1 Cycle

WIRING DIAGRAM

Blower Motor

A/C Amplifier

A/C Amplifier

INSPECTION PROCEDURE

READ VALUE OF INTELLIGENT TESTER

DATA LIST / AIR CONDITIONER:

(a) Connect the intelligent tester to the DLC3.

(b) Turn the ignition switch on (IG) and push the intelligent tester main switch on.

(c) Select the item below in the DATA LIST, and read the display on the intelligent tester.

Item

Measurement Item / Display (Range)

Normal Condition

Diagnostic Note

BLOWER LEVEL

Blower motor speed level / min.: 0 level max.: 31 level

Increases in the range between 0 and 31 as the speed increase

-

The display is as specified in the normal condition.

REPLACE AIR CONDITIONING AMPLIFIER

CHECK ACTUATOR

(a) Set the actuator check mode (See page AC-45).

(b) Press the UPDr switch to set the step operation.

(c) Check the air flow level by hand.

Display Code

Blower level

0

0

1

1

2

17

3

17

4

17

5

17

6

17

7

17

8

17

9

31

Blower level changes in accordance with each display code.

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Go to step 3

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

INSPECT FUSE (HEATER)

Engine Room R/B and J/B:

HEATER Fuse

HDGD = D cum §□□ 00 0 0 0 0 0 s □□ 0 0 0 0 0 0 0 0 0 0 0 0 0 0

(a) Remove the HEATER fuse from the engine room R/B and J/B.

(b) Measure the resistance according to the value(s) in the table below.

Resistance

Tester item

Condition

Specified condition

HEATER fuse

Always

Below 1 Q

REPLACE FUSE (HEATER)

REPLACE FUSE (HEATER)

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - AIR CONDITIONING AMPLIFIER)

Blower Motor Connector Wire Harness View:

(a) Disconnect the connector from blower motor.

jrffU<D42)

Air Conditioning Amplifier Connector Wire Harness View:

(b) Disconnect the connector from the A/C amplifier.

(c) Measure the resistance according to the value(s) in the table below.

Resistance

Tester connection (Symbols)

Condition

Specified condition

D37-11 (BLW) - D42-2 (SI)

Always

Below 1 Q

D37-11 (BLW) - Body ground

Constant

10 kQ or higher

REPAIR OR REPLACE HARNESS AND CONNECTOR

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BODY GROUND)

Blower Motor Connector Front View:

n f

IHf

1 n

(D42)

A

2

3

-4

GND

I041124E07

(a) Measure the resistance according to the value(s) in the table below. Resistance

Tester connection (Symbols)

Condition

Specified condition

D42-1(GND) - Body ground

Constant

Below 1 Q

REPAIR OR REPLACE HARNESS AND CONNECTOR

CHECK HARNESS AND CONNECTOR (BLOWER MOTOR - BATTERY)

(a) Measure the voltage according to the value(s) in the table below. Voltage

Tester connection (Symbols)

Condition

Specified condition

D42-1(+B) - Body ground

Constant

REPAIR OR REPLACE HARNESS AND CONNECTOR

INSPECT BLOWER MOTOR

Blower Motor Connector Front View:

Blower Motor Connector Front View:

(a) Remove the blower motor.

(b) Connect positive (+) lead to terminal 2 of the blower motor connector and negative (-) lead to terminal 1. OK:

Blower motor operates smoothly. NOTICE:

While using the battery during inspection, do not bring the positive and negative tester probes too close to each other as a short circuit may occur.

REPLACE BLOWER MOTOR

INSPECT AIR CONDITIONING AMPLIFIER (BLW - BODY GROUND)

(a) Reconnect the connector to the blower motor.

(b) Reconnect the connector to the A/C amplifier.

(c) Remove the A/C amplifier with connectors still connected.

(d) Turn the ignition switch on (IG).

f

500

msec./Division

2 V/ Division

(f) Measure the waveform between terminal BLW (D37-11) of the A/C amplifier and body ground. HINT:

Waveform varies with the blower level.

REPLACE AIR CONDITIONING AMPLIFIER

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

Compressor Circuit

DESCRIPTION

When the A/C switch is turned on, the magnetic clutch ON signal is sent from the MGC terminal of the A/ C amplifier. Then, the MG CLT relay turns on to operate the magnetic clutch.

WIRING DIAGRAM

Engine Room J/B Assembly

MG CLT Relay

Instrument Panel J/B

12 1C

A/C IG1 Relay COMP

From Ignition SW (*1) To Body Ground Power Source ECU (*2)~

From Ignition SW

From Battery

(*1): w/o Smart Key System (*2): w/ Smart Key System

w/ Magnet Clutch Compressor Assembly

A/C Amplifier /

INSPECTION PROCEDURE

PERFORM ACTIVE TEST BY INTELLIGENT TESTER

(a) Connect the intelligent tester to DLC3.

DATA LIST / AIR CONDITIONER:

(b) Turn the ignition switch on (IG) and push the intelligent tester main switch on.

(c) Select the item below in the ACTIVE TEST and then check that the relay operates.

DATA LIST / AIR CONDITIONER:

Item

Measurement Item / Display (Range)

Diagnostic Note

A/C MAG CLUTCH

Magnetic clutch relay / OFF,ON

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Go to step 2

PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

INSPECT FUSE (A/C COMP)

Instrument Panel J/B:

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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