Nissan Altima 2007-2012 Service Manual: Insufficient cooling

Component Function Check

SYMPTOM: Insufficient cooling

INSPECTION FLOW

1. CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - TEMPERATURE DECREASE

1. Press the A/C switch.

2. Turn temperature control dial counterclockwise to maximum cold.

3. Check for cold air at discharge air outlets.

Can a symptom be duplicated? YES >> GO TO 3

NO >> GO TO 2

2. CHECK FOR ANY SYMPTOMS

Perform a complete operational check and check for any symptoms. Refer to HAC-102, "Description & Conditions".

Does another symptom exist? YES >> Refer to HAC-155, "Symptom Matrix Chart".

NO >> System OK.

3. CHECK FOR SERVICE BULLETINS

Check for any service bulletins.

>> GO TO 4

4. CHECK DRIVE BELTS

Check A/C compressor belt tension. Refer to EM-16, "Checking Drive Belts" (QR25DE) or EM-121, "Checking Drive Belts" (VQ35DE).

Is the inspection result normal? YES >> GO TO 5

YES >> GO TO 5 NO >> Adjust or replace compressor belt. Refer to EM-16, "Removal and Installation" (QR25DE) or EM- 121, "Removal and Installation" (VQ35DE).

5. CHECK AIR MIX DOOR MOTOR OPERATION

Check and verify air mix door mechanism for smooth operation.

Does air mix door operate correctly? YES >> GO TO 6

NO >> Repair or replace air mix door control linkage.

6. CHECK COOLING FAN MOTOR OPERATION

Check and verify cooling fan motor for smooth operation.

Does cooling fan motor operation correctly? YES >> GO TO 7

NO >> Check cooling fan motor. Refer to EC-949, "Component Function Check" (QR25DE) or EC-1473, "Component Function Check" (VQ35DE).

7. CHECK RECOVERY/RECYCLING EQUIPMENT BEFORE USAGE

Check recovery/recycling equipment before connecting to vehicle. Verify there is no pressure in the recovery/ recycling equipment by checking the gauges. If pressure exists, recover refrigerant from equipment lines.

>> GO TO 8

8. CHECK REFRIGERANT PURITY

1. Connect recovery/recycling equipment to vehicle.

2. Confirm refrigerant purity in supply tank using recovery/recycling and refrigerant indentifier.

Is the inspection result normal? YES >> GO TO 9

NO >> Check contaminated refrigerant. Refer to HA-24, "HFC-134a (R-134a) Service Procedure".

9. CHECK REFRIGERANT PRESSURE

Check refrigerant pressure with manifold gauge connected. Refer to HAC-160, "Trouble Diagnosis For Abnormal Pressure".

Is the inspection result normal? YES >> Perform diagnostic work flow. Refer to HAC-157, "Diagnostic Work Flow".

NO >> GO TO 10

10. CHECK FOR EVAPORATOR FREEZE UP

Start engine and run A/C. Check for evaporator freeze up.

Does evaporator freeze up? YES >> Perform diagnostic work flow. Refer HAC-157, "Diagnostic Work Flow".

NO >> GO TO 11

11. CHECK AIR DUCTS

Check ducts for air leaks.

Is the inspection result normal? YES >> System OK.

NO >> Repair air leaks.

Diagnostic Work Flow

*1 HA-27, "Checking System for Leaks Using the Fluorescent Leak Detector"

*2 HA-35, "Removal and Installation for Compressor - QR25DE Models" or HA-36, "Removal and Installation for Compressor - VQ35DE Models"

*3 HAC-122, "Diagnosis Procedure"

*4 HAC-160, "Trouble Diagnosis For Abnormal Pressure"

*5 HAC-122, "Diagnosis Procedure"

*1 VTL-15, "Removal and Installation"

*2 HAC-127, "Diagnosis Procedure"

*3 HAC-131, "Diagnosis Procedure"

*4 EM-16, "Checking Drive Belts" (QR25DE) or EM-121, "Checking Drive Belts" (VQ35DE)

*5 HA-35, "Removal and Installation for Compressor - QR25DE Models" or HA-36, "Removal and Installation for Compressor - VQ35DE Models"

Performance Chart

TEST CONDITION

Testing must be performed as follows:

TEST READING

Recirculating-to-discharge Air Temperature Table

Ambient Air Temperature-to-operating Pressure Table

Trouble Diagnosis For Abnormal Pressure

Whenever system's high and/or low side pressure is abnormal, diagnose using a manifold gauge. The marker above the gauge scale in the following tables indicates the standard (normal) pressure range. Since the standard (normal) pressure differs from vehicle to vehicle, refer to Ambient Air Temperature-to-operating Pressure Table above.

Both High- and Low-pressure Sides are Too High

High-pressure Side is Too High and Low-pressure Side is Too Low

High-pressure Side is Too Low and Low-pressure Side is Too High

Both High- and Low-pressure Sides are Too Low

Low-pressure Side Sometimes Becomes Negative

Low-pressure Side Becomes Negative

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