Circuit Description
The PCM will activate the A/C clutch relay when the PCM detects that A/C has been requested. When the PCM activates the relay, voltage should be present at both the A/C compressor clutch and the A/C clutch status circuit at the PCM.
Conditions for Setting the DTC
The PCM commands the A/C ON and the PCM detects no voltage on the A/C clutch status line for more than 5.0 seconds.
Action Taken When the DTC Sets
| • | The powertrain control module (PCM) stores the DTC information into memory when the diagnostic runs and fails. |
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A last test failed, or the current DTC, clears when the diagnostic runs and does not fail. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if failures are not reported by this or any other emission related diagnostic. |
| • | Use a scan tool in order to clear the MIL/DTC. |
Diagnostic Aids
A/C Clutch Relay Underhood Electrical Center Terminal Identification | |||
|---|---|---|---|
Front of Vehicle | |||
Left Side of Vehicle | Ignition | Load | Right Side of Vehicle |
Ignition | Control | ||
The following may cause an intermittent:
| • | Mis-routed harness |
| • | Rubbed through wire insulation |
| • | Broken wire inside the insulation |
For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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A problem that may prevent the compressor from engaging may or may not cause a DTC P1546.
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If the scan tool indicates that the A/C Status is ON, this indicates that the status circuit is OK.
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Using the Freeze Frame and/or Failure Records data may aid in locating an intermittent condition. If you cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data can help determine how many miles since the DTC set. The Fail Counter and Pass Counter can also help determine how many ignition cycles the diagnostic reported a pass and/or a fail. Operate vehicle within the same freeze frame conditions (RPM, load, vehicle speed, temperature etc.) that you observed. This will isolate when the DTC failed.
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This step checks whether the ignition voltage is available at the relay.
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This step determines if the A/C relay is at fault or the A/C status circuit is at fault. If the A/C clutch engages, this indicates that the A/C Status circuit is OK.
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This DTC will not report a pass. The scan tool status for this DTC will never report a pass. The scan tool will only display when the diagnostic fails. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Does the A/C clutch operate properly? | -- | |||
Monitor the A/C Status display on the Engine 1 Data List using a scan tool. Does the scan tool indicate A/C Status as ON? | -- | |||
Does the scan tool indicate that this diagnostic failed this ignition? | -- | Refer to Diagnostic Aids | ||
Does the test lamp illuminate? | -- | |||
Jump the ignition feed circuit to the A/C clutch status circuit (load) at the underhood electrical center using a fused jumper wire. Refer to Diagnostic Aids for terminal identification. Does the A/C clutch engage? | -- | |||
7 | Repair the faulty A/C clutch relay connection or faulty A/C clutch relay. Refer to A/C Relay replacement. Is the action complete? | -- | -- | |
8 | Repair the open A/C clutch status circuit from the splice to the PCM. Did you find and repair the condition? | -- | ||
9 | Repair the open ignition feed circuit to A/C relay. Is the action complete? | -- | -- | |
10 | Repair the open in A/C status circuit from A/C relay to splice. Is the action complete? | -- | -- | |
11 |
Important:: Program the replacement PCM. Refer to Powertrain Control Module/Throttle Actuator Control Module Replacement . Replace the PCM. Is the action complete? | -- | -- | |
Does the scan tool indicate that this failed? | -- | |||
13 | Select the Capture Info option and the Review Info option using the scan tool. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK |
