A/C System Service Procedure (AC93-003)

Publication date: 1993-04-16
Reference number: AC93-003

A/C SYSTEM SERVICE PROCEDURE

TECHNICAL SERVICE BULLETIN

Reference Number(s): AC93-003, Date of Issue: April 16, 1993

AIR CONDITIONING SYSTEM SERVICE

Model All Lexus Models

Group Heating & Air Conditioning

Bulletin No. AC93-003

Date April 16, 1993

SERVICE INFORMATION

In recent years, there has been a growing concern/for the effects of chemical substances on the environment throughout the world. One of the substances that has attracted attention is the R-12 refrigerant used in automotive air conditioning (A/C) systems.

The chemical name for R-12 is Chlorofluorocarbon (CFC) and it has been identified along with CFC's from other sources as being a contri-buting factor in the depletion of the ozone layer in the earth's atmosphere. The ozone layer provides protection from the harmful effects of the sun's ultraviolet rays. See Fig 1. Consequently, it is very important to minimize the amount of refrigerant released into the atmosphere.

Fig 1: Damaged Zone Layer

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

When servicing the A/C system it is mandatory to use a Lexus Approved refrigerant recovery machine (Lexus P/N 00002-01396-02) or its equivalent, and to use only the minimum amount of refrigerant necessary to test or charge the system. See Fig 2.

Fig 2: Recovering A/C Refrigerant

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

To aid you in making quick. accurate diagnosis and repair of low refrigerant level conditions, the following inspection procedures have been developed.

QUICK CHECKS OF REFRIGERANT VOLUME

Inspect the condition of the refrigerant flowing through the sight glass, according to the indicators shown in Fig 3.

PROPERLY CHARGED SYSTEM

Almost no air bubbles are seen in the flow of refrigerant. When raising the engine speed gradually from idle to 1500 rpm, the bubbles disappear, making the refrigerant transparent.

INSUFFICIENTLY CHARGED SYSTEM

Air bubbles seen continuously in the refrigerant.

EXCESSIVELY CHARGED SYSTEM

No air bubbles seen in the refrigerant flow.

Fig 3: Checking System Charge

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

LEAK DETECTION

Identifying the exact location of A/C refrigerant leaks must be done with great care and can sometimes be difficult

Ensure that at least 1 lb. (450 g) of A/C refrigerant is in the system.
Install a gauge set and operate the A/C system to obtain normal system pressures. (Low: 21 - 28 psi, Hi: 206 - 213 psi)
Stop engine and allow low side pressure to peak.
Always use a proper gas leak detector for the refrigerant you are working with. See Fig 4.
1. Do not use propane type testers.
2. Always allow full warm-up of electronic type testers.
3. Calibrate instrument according to manufacturers instructions.
4. Do not get probe wet or oily, etc.
Inspect the A/C system according to the following A/C system inspection procedures.

NOTE: Before performing any repairs, connect and use the refrigerant recovery machine.

Fig 4: Proper and Improper Leak Detectors

A/C SYSTEM INSPECTION PROCEDURE (Refer to Fig 5)

Fig 5: A/C System Inspection Procedure

GAS LEAK INSPECTION

Fig 6: A/C System Pipe Connection

Fig 7: Locating Gas Leaks

AIR CONDITIONING SYSTEM COOLING UNIT COMPONENT LOCATION

Refer to Fig 8 for the A/C system component locations for single evaporator applicable to all passenger cars.

Fig 8: A/C System Cooling Unit Component Location