Insufficient Heating

INSUFFICIENT HEATING

Component Function Check

SYMPTOM: Insufficient heating

INSPECTION FLOW


1. CONFIRM SYMPTOM BY PERFORMING OPERATIONAL CHECK - TEMPERATURE INCREASE

1.Press the AUTO switch.
2.Turn the temperature control dial (driver) clockwise until 32�C (90�F) is displayed.
3.Check for hot air at discharge air outlets.
Is the inspection result normal?
YES- GO TO 2.
NO- Perform complete system operational check. Operational Check (Front) or
Operational Check (Rear).

2. CHECK FOR SERVICE BULLETINS

Check for any service bulletins.
- GO TO 3.

3. PERFORM SELF-DIAGNOSIS

Perform self-diagnosis. A/C Auto Amp. Self-Diagnosis.
Is the inspection results normal?
YES- GO TO 4.
NO- A/C System Self-Diagnosis Code Chart.

4. CHECK ENGINE COOLING SYSTEM

1.Check for proper engine coolant level. Initial Inspection and Diagnostic Overview ("System
Inspection".
2.Check hoses for leaks or kinks.
3.Check radiator cap. Initial Inspection and Diagnostic Overview (VQ-40DE) or Initial Inspection and Diagnostic Overview
(VK-56DE).
4.Check for air in cooling system.
- GO TO 5.

5. CHECK AIR MIX DOOR OPERATION

Check the operation of the air mix door.
Is the inspection result normal?
YES- GO TO 6.
NO- Check the air mix door motor circuit. Component Function Check or Component Function Check.

6. CHECK AIR DUCTS

Check for disconnected or leaking air ducts.
Is the inspection result normal?
YES- GO TO 7.
NO- Repair all disconnected or leaking air ducts.

7. CHECK HEATER HOSE TEMPERATURES

1.Start engine and warm it up to normal operating temperature.
2.Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be warm.
Is the inspection result normal?
YES- Hot inlet hose and a warm outlet hose: GO TO 8.
NO- - Inlet hose cold: GO TO 11.

- Both hoses warm: GO TO 9.

8. CHECK ENGINE COOLANT SYSTEM

Check engine coolant temperature sensor.
Is the inspection result normal?
YES- System OK.
NO- Repair or replace as necessary. Retest.

9. CHECK HEATER HOSES

Check heater hoses for proper installation.
Is the inspection result normal?
YES- System OK.
NO- 1.Back flush heater core.
2.Drain the water from the system.
3.Refill system with new engine coolant. Service and Repair
(VQ-40DE) or Service and Repair (VK-56DE).
4.GO TO 10 to retest.

10. CHECK HEATER HOSE TEMPERATURES

1.Start engine and warm it up to normal operating temperature.
2.Touch both the inlet and outlet heater hoses. The inlet hose should be hot and the outlet hose should be warm.
Is the inspection result normal?
YES- System OK.
NO- Replace heater core. Removal And Installation.

11. CHECK HEATER PUMP (VQ40DE ONLY)

Check the operation of the heater pump valve. Heater Pump.
Is the inspection result normal?
YES- System OK.
NO- Replace heater pump. Heater Pump.