Circuit Description
Ignition voltage is supplied directly to the A/C compressor clutch relay. The powertrain control module (PCM) controls the relay by grounding the control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line which is monitored by the PCM. When the PCM is commanding a component on, the voltage of the control circuit should be near 0 volts. When the PCM is commanding the control circuit to a component off, the voltage potential of the circuit should be near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this DTC will set.
The PCM will monitor the control circuit for the following:
| • | A short to ground |
| • | A short to voltage |
| • | An open circuit |
| • | An open relay coil |
| • | An internally shorted or excessively low resistance relay coil. |
Conditions for Running the DTC
| • | The ignition voltage is between 9.0 and 18.0 volts. |
| • | The engine is running. |
Conditions for Setting the DTC
| • | A short to ground, an open circuit, or a short to battery voltage is detected on the control circuit. |
| • | The condition is present for at least 30 seconds. |
Action Taken When the DTC Sets
| • | The PCM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | The PCM turns the MIL Off after three consecutive drive trips that the diagnostic runs and does not fail. |
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A History DTC clears after forty consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures. |
| • | Use a scan tool in order to clear the MIL diagnostic trouble code. |
Diagnostic Aids
If condition not present refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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Listen for an audible click when the A/C compressor clutch relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
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Tests for voltage at the coil side of the A/C compressor clutch relay. The 10 Amp fuse supplies power to the coil side of the A/C compressor clutch relay.
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Verifies that the powertrain control module is providing ground to the A/C compressor clutch relay.
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Tests if ground is constantly being applied to the A/C compressor clutch relay.
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Tests for a short to voltage or an open.
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Perform the recalibration procedure for the powertrain control module.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: HVAC Schematics | |||
1 | Did you perform the powertrain HVAC Diagnostic System Check? | Go to Step 2 | |
2 |
Important: The ambient air temperature must be above 3 degrees Celsius (38 degrees Fahrenheit).
Does the A/C compressor operate? | Go to Step 3 | |
Does the A/C Relay turn ON and OFF with each command? | Go to Diagnostic Aids | Go to Step 4 | |
Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 | |
Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 6 | |
Does the test lamp remain illuminated with each command? | Go to Step 8 | Go to Step 7 | |
Test the control circuit of the A/C compressor clutch relay for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 | |
8 | 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 14 | Go to Step 10 |
9 | 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 14 | Go to Step 12 |
10 | Inspect for poor connections at the harness connector of the powertrain control module. 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 14 | Go to Step 13 |
11 | Repair the battery positive voltage circuit of the A/C compressor clutch relay. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | -- |
12 | 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 14 | -- |
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Important: Perform the programming procedure for the powertrain control module . Replace the powertrain control module. Refer to Powertrain Control Module Replacement in Engine Controls. Did you complete the replacement? | Go to Step 14 | -- | |
14 |
Does the DTC reset? | Go to Step 3 | System OK |
