P1546

Diagnostic Chart:

Wiring Diagram:

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 RUNNING THE DTC
The A/C is requested.

CONDITIONS FOR SETTING THE DTC
The PCM commands the A/C ON and the PCM does not detect a voltage on the A/C clutch status line for more than 5.0 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The 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 History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
- A last test failed (Current DTC) will clear when the diagnostic runs and does not fail.
- The PCM battery voltage is interrupted.
- Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS
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. Testing and Inspection

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
2. A problem that may prevent the compressor from engaging may or may not cause a DTC P1546.
3. It the scan tool indicates that the A/C Status is ON, this indicates that the status circuit is OK.
4. 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.
5. This step checks whether the ignition voltage is available at the relay.
6. 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.
12. The repair is not complete if the scan tool indicates that the diagnostic ran and failed.