Test Description
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These DTCs cover the Low Speed Buss Line of GM LAN. This is the circuit that carries the A/C request signal.
Step | Action | Value(s) | 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 perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
Do any of the following DTCs set U2100, U2103, U2105-U2199? | -- | Go to Data Link References | Go to Step 3 | |
3 |
Does the A/C compressor operate? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 4 |
Is the engine coolant temperature indicator illuminated? | Go to Engine Overheating | Go to Step 5 | ||
5 |
Are the low and the high side pressure values within the allowable limits for the recorded ambient air temperature and are the pressure values within 103 kPa (15 psi) of each other? | Above 16°C (60°F) 345 kPa (50 psi) Above 24°C (75°F) 483 kPa (70 psi) Above 33°C (90°F) 690 kPa (100 psi) | Go to Step 6 | Go to Leak Testing |
6 |
Is the scan tool A/C refrigerant pressure sensor parameter and the ACR 2000 pressure value within 15 psi of each other? | Go to Step 7 | Go to Step 14 | |
7 | With a scan tool, view the ambient air temperature in the HVAC system data. Is the ambient air temperature below 3°C (38F°)? | Go to Step 17 | Go to Step 8 | |
8 |
Does the test lamp illuminate? | -- | Go to Step 9 | Go to Step 10 |
9 | Test the ground circuit of the A/C compressor clutch for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 13 |
10 | Test the voltage supply circuit of the A/C compressor clutch for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 11 |
11 |
Does the test lamp illuminate? | -- | Go to Step 12 | Go to Step 22 |
12 | Inspect for poor connections at the A/C compressor clutch relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 23 |
13 | 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 . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 24 |
14 |
Does the test lamp illuminate? | -- | Go to Step 18 | Go to Step 15 |
15 | Test the low reference circuit of the A/C refrigerant pressure sensor for a high resistance or for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 16 |
16 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 25 |
17 | Inspect the ambient air temperature sensor circuits for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 20 |
18 | 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 . Did you find and correct the condition? | Go to Step 26 | Go to Step 19 | |
19 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement . Did you complete the replacement? | Go to Step 26 | -- | |
20 | Inspect for poor connections at the harness connector of the ambient air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 26 | Go to Step 21 |
21 | Replace the ambient air temperature sensor. Refer to Ambient Air Temperature Gage Sensor Replacement . Did you complete the replacement? | -- | Go to Step 26 | -- |
22 | Repair the battery positive voltage circuit of the A/C compressor clutch relay. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 26 | -- |
23 | Replace the A/C compressor clutch relay. Refer to Relay Replacement . Did you complete the replacement? | -- | Go to Step 26 | -- |
24 | Replace the A/C compressor clutch. Refer to Compressor Clutch Assembly Replacement . Did you complete the replacement? | -- | Go to Step 26 | -- |
25 | Replace the HVAC control module. Refer to HVAC Module Assembly Replacement . Did you complete the replacement? | -- | Go to Step 26 | -- |
26 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2 |
