Air Conditioning (A/C) System Performance Test. Chevrolet Blazer

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2004 🢒 Blazer - 4WD 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Air Conditioning (A/C) System Performance Test

Table 1:

A/C Performance Table

This test measures the operating efficiency of the A/C system under the following conditions:

•	The current ambient air temperature

•	The current relative humidity

•	The high side pressure of the A/C system

•	The low side pressure of the A/C system

•	The temperature of the air being discharged into the passenger compartment

Test Description

The numbers below refer to the step numbers on the diagnostic table.

This step determines if the A/C system has at least the minimum refrigerant charge required to operate the system without damage.

This step measures the performance of the A/C system.

This step is to allow for vehicle variations as well as high ambient temperatures.

Step

Action

Values

Yes

Important:

•	The ambient air temperature must be at least 16°C (60°F) .

•	Do not induce additional air flow across the front of the vehicle during the test.

•	If you were sent here from a DTC diagnostic table, clear the DTC upon completion of this test.

Park the vehicle inside or in the shade.
Open the windows in order to ventilate the interior of the vehicle.
If the A/C system was operating, allow the A/C system to equalize for about 2 minutes.
Turn OFF the ignition.
Install the J 43600 .
Record the ambient air temperature displayed on the J 43600 .
Record the low and high side STATIC pressure readings.

Are both the low side and high side pressures within the specified value?

More than 16°C (60°F) - 345 kPa (50 psi)

More than 24°C (75°F) - 483 kPa (70 psi)

More than 33°C (90°F) - 690 kPa (100 psi)

Go to Step 2

Go to Leak Testing

Important: Record the relative humidity and the ambient air temperature at the time of the test.

Close the vehicle doors and windows.
Open the drivers door window 12.7 - 15.2 cm (5-6 inches).
Select the following HVAC control settings:

•	The A/C is ON

•	The maximum blower speed

•	The Vent mode

•	The coldest temperature setting

•	All A/C outlets are OPEN

Install the temperature probes of the J 43600 in the left and right center A/C air outlets.
Apply the parking brake.
Place the transaxle/transmission in one of the following positions:

•	PARK (Automatic)

•	NEUTRAL (Manual)

Start the engine.
Operate the A/C system for 5 minutes.
Inspect A/C components for the following conditions:

•	Abnormal frost areas

•	Unusual noises

Important: Press the RESET button, before using the print function of the J 43600 .

Print the following information:

•	The outlet air temperatures

•	The low-side pressure

•	The high-side pressure

Compare the low and high side pressures and the output temperatures to the A/C performance table below.

Does all the data recorded fall within the specified ranges of the A/C performance table?

Go to Step 4

Go to Step 3

If the pressures and temperatures recorded do not fall within the specified ranges:

Continue to operate the A/C system for an additional 5 minutes.
RESET the J 43600 and record the pressures and temperatures again.
Compare the low and high side pressures and the output temperature to the A/C performance table.

Does all the data recorded fall within the specified ranges of the A/C performance table?

Go to Step 8

Go to Step 4

Do the high and low side pressures fall within the specified ranges, but the outlet temperatures do not?

Go to Air Conditioning (A/C) Diagnostics - Pressure Zone A

Go to Step 5

Is the low side pressure greater than the specified range, but the high side pressure within or less than the specified range?

Go to Air Conditioning (A/C) Diagnostics - Pressure Zone B

Go to Step 6

Are the low and high side pressures both greater than the specified ranges?

Go to Air Conditioning (A/C) Diagnostics - Pressure Zone C

Go to Step 7

Is the high side pressure greater than the specified range, but the low side pressure is within or less than the specified range?

Go to Air Conditioning (A/C) Diagnostics - Pressure Zone D

Go to Step 8

Operate the system in order to verify the test results.

Did you find the same results?

System OK

Go to Symptoms - HVAC Systems - Manual

A/C System Pressure -- Zone Classification

A/C Performance Table

Ambient Air Temperature	Relative Humidity	Service Port Pressure		Maximum Left Center Discharge Air Temperature
Ambient Air Temperature	Relative Humidity	Low Side	High Side	Maximum Left Center Discharge Air Temperature
13-18°C (55-65°F)	0-100%	145-186 kPa (21-27 psi)	931-1207 kPa (135-175 psi)	6°C (43°F)
19-24°C (66-75°F)	Below 40%	172-214 kPa (25-31 psi)	1103-1379 kPa (160-200 psi)	7°C (45°F)
19-24°C (66-75°F)	Above 40%	172-214 kPa (25-31 psi)	1172-1448 kPa (170-210 psi)	8°C (46°F)
25-29°C (76-85°F)	Below 35%	179-221 kPa (26-32 psi)	1034-1310 kPa (150-190 psi)	9°C (48°F)
	35-60%	186-228 kPa (27-33 psi)	1103-1379 kPa (160-200 psi)	10°C (50°F)
	Above 60%	193-234 kPa (28-34 psi)	1103-1379 kPa (160-200 psi)	9°C (49°F)
30-35°C (86-95°F)	Below 30%	241-283 kPa (35-41 psi)	1379-1655 kPa (200-240 psi)	13°C (55°F)
	30-50%	241-283 kPa (35-41 psi)	1379-1655 kPa (200-240 psi)	13°C (56°F)
	Above 50%	255-296 kPa (37-43 psi)	1379-1655 kPa (200-240 psi)	14°C (57°F)
36-41°C (96-105°F)	Below 20%	255-310 kPa (37-45 psi)	1655-1931 kPa (240-280 psi)	16°C (60°F)
	20-40%	283-338 kPa (41-49 psi)	1689-1965 kPa (245-285 psi)	18°C (64°F)
	Above 40%	310-365 kPa (45-53 psi)	1724-1827 kPa (250-265 psi)	16°C (61°F)
42-46°C (106-115°F)	Below 20%	303-359 kPa (40-48 psi)	1724-1999 kPa (250-290 psi)	17°C (62°F)
42-46°C (106-115°F)	Above 20%	303-359 kPa (44-52 psi)	1793-2068 kPa (260-300 psi)	19°C (67°F)
47-49°C (116-120°F)	Below 30%	324-379 kPa (47-55 psi)	1999-2275 kPa (290-330 psi)	21°C (70°F)