Cabin Heat Pump Purge Cycle (between 2°C (37.4°F) and 18°C (64.4°F) )

Compressor Motor

HTCM Data

amps

2 amps

Reversing Valve

HTCM Data

On/Off

On

Primary Valve

HTCM Data

On/Off

Off

Secondary Valve

HTCM Data

On/Off

Off

Cabin Heat Pump Time-out Period (between 2°C (37.4°F) and 18°C (64.4°F) )

Compressor Motor

HTCM Data

amps

0 amps

Reversing Valve

HTCM Data

On/Off

Off

Primary Valve

HTCM Data

On/Off

On

Secondary Valve

HTCM Data

On/Off

Off

Cabin Heat Pump Run Cycle (between 2°C (37.4°F) and 18°C (64.4°F) )

Compressor Motor

HTCM Data

amps

2 amps

Reversing Valve

HTCM Data

On/Off

Off

Primary Valve

HTCM Data

On/Off

On

Secondary Valve

HTCM Data

On/Off

Off

Did you perform the HVAC System Check?

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Go to Step 2

Go to HVAC System Check

1. Turn ignition ON.
2. Turn the HVAC Mode Select Switch to max A/C.

Does the A/C condenser cooling fan turn on?

--

Go to Step 3

Go to Air Conditioning (A/C) Condenser Fan System Check

1. Turn A/C mode select switch to VENT.
2. Using a Scan Tool observe the Mode Valve Actuator Commanded display.
3. Turn the temperature control knob from cold to hot and hot to cold.

Does the scan tool indicate the mode door is operating properly?

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Go to Step 5

Go to Step 4

Locate and repair problem with mode door. The mode door may be observed by removing the blower motor resistor.

Did you complete the repair?

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Go to HVAC System Check

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1. Using a Scan Tool observe the Mode Valve Actuator Commanded and Mode Valve Actuator Feedback Ckt. display.
2. Turn the HVAC Mode Select Switch to Max A/C.

Does the scan tool display the specified values?

Stop,  3.5 Volts and between 10  -38 steps

Go to Step 6

Go to Step 4

Connect high and low side refrigerant pressure gauges. Both pressures should be approximately equal.

Are both pressures above the specified value?

350 kPa

Go to Step 10

Go to Step 7

Are both pressures between the specified values?

70-350 kPa

Go to Step 8

Go to Step 9

1. Leak test system.
2. Add refrigerant if needed. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
3. Repair any leaks.

Did you complete the repair?

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Go to HVAC System Check

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1. Add 1 lb. of refrigerant. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
2. Leak test system.
3. Repair any leaks.

Did you complete the repair?

--

Go to HVAC System Check

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Important:: This test was designed for typical garage conditions: 20-30°C (68-86°F) and no sunload. Normal discharge air temperature is typically at least 10°C (50°F) cooler than ambient temperature for cabin air conditioning mode. Follow this test procedure exactly.

1. Close all the vehicle windows and doors.
2. Set A/C controls to: Max A/C mode, high blower, and temperature control to full cold.
3. Allow system to operate for 20 minutes.
4. Feel liquid line on both sides of the orifice (expansion) tube

Is there a noticeable temperature difference?

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Go to Step 12

Go to Step 11

Orifice (expansion) tube is missing, damaged, or shifted.

1. Install or replace orifice (expansion) tube.
2. Evacuate and recharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
3. Leak test system.
4. Note discharge air temperature after 20 minutes of operation.

Is the discharge temperature within specifications?

10°C (50°F) below ambient temperature

Go to HVAC System Check

Go to Step 10

Observe low and high side pressures after the system has been operating for 20 minutes. Refer to A/C System Performance Chart in HVAC Compressor Controls System Check .

Are the low and high side pressures within specifications?

--

Go to Step 14

Go to Step 13

Is the high side pressure within specifications?

--

Go to Step 15

Go to Step 18

All components of the refrigerant system are functioning properly. If insufficient performance exists, the refrigerant reversing valve may be at fault.

Is the heating performance still insufficient?

--

Go to HVAC Compressor Controls System Check

System OK

1. Continue operating the A/C.
2. Feel the liquid line on both sides of the orifice (expansion) tube.

Is the tube cold?

--

Go to Step 16

Go to Step 17

Restriction in high side.

1. Discharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
2. Locate and remove restriction
3. Evacuate and recharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
4. Perform leak test.

Did you complete the repair?

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Go to Step 10

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Refrigerant overcharge or air in the system.

1. Evacuate and recharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
2. Perform leak test.

Did you complete the repair?

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Go to Step 10

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Are the compressor high and low side pressures within 210 kPa of each other?

--

Go to HVAC Compressor Motor Insulation Test

Go to Step 19

Is the low side pressure 175-245 kPa?

--

Go to Step 20

Go to Step 10

Refrigerant undercharged.

Add 1 lb. of refrigerant to system.

Does performance improve?

--

Go to Step 21

Go to Step 22

1. Leak test system.
2. If a leak is found, repair leak.
3. Evacuate and recharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
4. Repeat leak test.

Did you complete the repair?

--

Go to Step 10

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1. Discharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
2. Check orifice (expansion) tube. if plugged, remove orifice, clear lines, and replace orifice with new part.
3. Evacuate and recharge system. Refer to Refrigerant Recovery And Recharging in Heater, Ventilation, and Air Conditioning.
4. Repeat leak test.

Did you complete the repair?

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Go to Step 10

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