HVAC Compressor Clutch Does Not Engage 4.3L
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Placing the mode switch in any position other than OFF, along with placing the air temperature control switch in a cold setting, activates A/C operation. For the purpose of this and future steps where A/C operation is necessary, bi-level mode is used for consistent testing.
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The HVAC control assembly is inoperative when the module does not respond to any operator control requests.
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Ensure to test both A/C request signal circuits of the A/C high pressure sensor for the listed conditions.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set. | |||
1 | Did you review the HVAC operation and perform the necessary inspections? | Go to Step 2 | |
Does the scan tool indicate that the ECT parameter is below 121°C (250°F)? | Go to Step 3 | Go to Engine Overheating | |
|
Important: For A/C compressor operation, ambient air temperature must be above 3°C (38°F).
Does the A/C compressor clutch engage? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
4 |
Are the side pressure values within the specifications for the ambient air temperature, and within 103 kPa (15 psi) of each other? | Go to Step 5 | Go to Leak Testing in Heating, Ventilation and Air Conditioning |
Is the HVAC control assembly inoperative? | Go to Step 18 | Go to Step 6 | |
6 |
Does the scan tool indicate that the A/C Request Signal parameter is YES? | Go to Step 8 | Go to Step 7 |
7 |
Does the scan tool indicate that the A/C Request Signal parameter is YES? | Go to Step 31 | Go to Step 24 |
8 | Does the scan tool indicate the A/C Compressor Cycling Switch parameter is Normal? | Go to Step 10 | Go to Step 9 |
9 |
Does the scan tool indicate the A/C Compressor Cycling Switch parameter is Normal? | Go to Step 28 | Go to Step 20 |
10 | With a scan tool, command the A/C Relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? | Go to Step 14 | Go to Step 11 |
11 |
Does the test lamp illuminate? | Go to Step 12 | Go to Step 26 |
12 |
Does the test lamp turn ON and OFF with each command? | Go to Step 27 | Go to Step 13 |
13 | Does the test lamp remain illuminated with each command? | Go to Step 17 | Go to Step 16 |
14 |
Does the test lamp illuminate? | Go to Step 15 | Go to Step 25 |
15 | Connect a 10-amp fused jumper wire between the switch side voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch. Does the A/C compressor clutch engage? | Go to Step 27 | Go to Step 22 |
16 | Test the control circuit of the A/C compressor clutch relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 32 |
17 | Test the control circuit of the A/C compressor clutch relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 32 |
18 | Test the ignition 3 voltage circuit of the HVAC control assembly for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 19 |
19 | Test the ground circuit of the HVAC control assembly for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 30 |
20 | Test the A/C low pressure switch signal circuit for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 21 |
21 | Test the ground circuit of the A/C low pressure switch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 32 |
22 | Test the A/C compressor clutch supply voltage circuit at the A/C compressor clutch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 23 |
23 | Test the ground circuit of the A/C compressor clutch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 29 |
Did you find and correct the condition? | Go to Step 39 | Go to Step 32 | |
25 | Repair the switch side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 39 | -- |
26 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 39 | -- |
27 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 33 |
28 | Inspect for poor connections at the harness connector of the A/C low pressure switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 34 |
29 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 36 |
30 | Inspect for poor connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 37 |
31 | Inspect for poor connections at the harness connector of the A/C high pressure switch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 35 |
32 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 39 | Go to Step 38 |
33 | Replace the A/C compressor clutch relay. Refer to Compressor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | Go to Step 39 | -- |
34 | Replace the A/C low pressure switch. Refer to Air Conditioning (A/C) Low Pressure Switch Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | Go to Step 39 | -- |
35 | Replace the A/C high pressure switch. Refer to Air Conditioning (A/C) High Pressure Switch Replacement in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | Go to Step 39 | -- |
36 | Replace the A/C compressor clutch coil. Refer to Air Conditioning Clutch Coil Removal and Air Conditioning Clutch Coil Installation in Heating, Ventilation, and Air Conditioning. Did you complete the replacement? | Go to Step 39 | -- |
37 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | Go to Step 39 | -- |
38 |
Important: Perform the programming procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 4.3L. Did you complete the replacement? | Go to Step 39 | -- |
39 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 4 |
HVAC Compressor Clutch Does Not Engage 2.2L
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Placing the mode switch in any position other than OFF, along with placing the air temperature control switch in a cold setting, activates A/C operation. For the purpose of this and future steps where A/C operation is necessary, bi-level mode is used for consistent testing.
-
The HVAC control assembly is inoperative when the module does not respond to any operator control requests.
Step | Action | Value | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views DEFINITION: The A/C compressor clutch will not engage when an A/C request has been made and a Powertrain DTC has not been set. | ||||
1 | Did you review the HVAC operation and perform the necessary inspections? | -- | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual in Engine Cooling |
Does the scan tool indicate that the ECT parameter is below 121°C (250°F)? | -- | Go to Step 3 | Go to Engine Overheating | |
|
Important: For A/C compressor operation, ambient air temperature must be above 3°C (38°F).
Does the A/C compressor clutch engage? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 4 | |
4 |
Are the pressure values within the specifications for the ambient air temperature, and within 103 kPa (15 psi) of each other? | -- | Go to Step 5 | Go to Leak Testing in Heating, Ventilation and Air Conditioning |
5 |
Are the high side pressure values within 103 kPa (15 psi) of each other? | -- | Go to Step 6 | Go to Step 19 |
Is the HVAC control assembly inoperative? | -- | Go to Step 18 | Go to Step 7 | |
7 |
Does the scan tool indicate that the A/C Request Signal parameter is YES? | -- | Go to Step 8 | Go to Step 30 |
8 | With a scan tool, observe the A/C High Side Pressure parameter in the powertrain data list. Does the scan tool indicate that the A/C High Side Pressure parameter is within the specified range? | 310-2930 kPa (45-425 psi) | Go to Step 12 | Go to Step 9 |
9 |
Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified value? | 2930 kPa (425 psi) | Go to Step 10 | Go to Step 23 |
10 |
Does the scan tool indicate that the A/C High Side Pressure parameter is less than the specified value? | 310 kPa (45 psi) | Go to Step 11 | Go to Step 24 |
11 |
Does the scan tool indicate that the A/C refrigerant pressure sensor parameter is greater than the specified value? | 2930 kPa (425 psi) | Go to Step 22 | Go to Step 21 |
12 | With a scan tool, command the A/C Relay ON and OFF. Does the A/C compressor clutch relay turn ON and OFF with each command? | -- | Go to Step 16 | Go to Step 13 |
13 |
Does the test lamp illuminate? | -- | Go to Step 14 | Go to Step 32 |
14 |
Does the test lamp turn ON and OFF with each command? | -- | Go to Step 33 | Go to Step 15 |
15 | Does the test lamp remain illuminated with each command? | -- | Go to Step 27 | Go to Step 26 |
16 |
Does the test lamp illuminate? | -- | Go to Step 17 | Go to Step 31 |
17 | Connect a 10-amp fused jumper wire between the switch side voltage circuit of the A/C compressor clutch relay and the A/C compressor clutch supply voltage circuit of the A/C compressor clutch. Does the A/C compressor clutch engage? | -- | Go to Step 33 | Go to Step 28 |
18 | Test the ignition 3 voltage circuit of the HVAC control assembly for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 20 |
19 | Test the ground circuit of the A/C pressure sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34 |
20 | Test the ground circuit of the HVAC control assembly for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 36 |
21 | Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
22 | Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 34 |
23 | Test the signal circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
24 | Test the signal circuit of the A/C refrigerant pressure sensor for a short to voltage, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 25 |
25 | Test the low reference circuit of the A/C refrigerant pressure sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
26 | Test the control circuit of the A/C compressor clutch relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
27 | Test the control circuit of the A/C compressor clutch relay for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
28 | Test the A/C compressor clutch supply voltage circuit of the A/C compressor clutch for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 29 |
29 | Test the ground circuit of the A/C compressor clutch for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 35 |
30 |
Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 37 |
31 | Repair the switch side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- |
32 | Repair the coil side voltage supply circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 43 | -- |
33 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 39 |
34 | Inspect for poor connections at the harness connector of the A/C refrigerant pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 38 |
35 | Inspect for poor connections at the harness connector of the A/C compressor clutch. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 40 |
36 | Inspect for poor connections at the harness connector of the HVAC control assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 41 |
37 | Inspect for poor connections at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 43 | Go to Step 42 |
38 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 43 | -- |
39 | Replace the A/C compressor clutch relay. Refer to Compressor Relay Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 43 | -- |
40 | Replace the A/C compressor clutch coil. Refer to Air Conditioning Clutch Coil Removal and Air Conditioning Clutch Coil Installation in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 43 | -- |
41 | Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement . Did you complete the replacement? | -- | Go to Step 43 | -- |
42 |
Important: Perform the programming procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 2.2L. Did you complete the replacement? | -- | Go to Step 43 | -- |
43 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 4 |
