P1546

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 through 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.

CONDITIONS FOR RUNNING THE DTC
- The ignition voltage is between 9.0-18.0 volts.
- The engine speed is more than 80 RPM.
- The PCM driver is activated.

CONDITIONS FOR SETTING THE DTC
- The PCM detects an improper voltage level on the output circuit that controls the A/C relay.
- The condition is present for at least 30 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The PCM will not illuminate the malfunction indicator lamp (MIL).
- The PCM stores the failure records.
- The A/C compressor clutch is disabled.

CONDITIONS FOR CLEARING THE DTC
- The DTC will become history if the PCM no longer detects a failure.
- The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
- The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-4:

Steps 5-11:

Steps 12-14:

The numbers below refer to the step numbers on the diagnostic table.
3. 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.
4. 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.
5. Verifies that the PCM is providing ground to the A/C compressor clutch relay.
6. Tests if ground is constantly being applied to the A/C compressor clutch relay.
7. Tests for a short to voltage or an open.
13. Perform the programming procedure for the PCM.