P1545 Code failures by brands


Description of DTC code P1545

Ignition voltage is sent directly to the A/C compressor clutch relay. This relay is controlled by the Powertrain Control Module (PCM), which grounds its control circuit using an internal solid-state device, known as a driver.

The primary function of the conductor is to supply the ground for the component being controlled. Each conductor has a fault line, which is monitored directly by the PCM. When this controller commands the activation of a component, the controller circuit voltage must be close to 0 volts. By the time the PCM commands the control circuit to turn off a component, this voltage should be close to the battery voltage.

If the fault detection circuit finds a different voltage than expected on the output circuit controlling the A/C compressor clutch relay, a line status fault occurs, and this will cause the P1545 OBD2 diagnostic code to be set.

Symptoms of fault code P1545

  • On certain vehicles the Check Engine light illuminates.
  • The air conditioning compressor remains off.

Causes of OBD2 P1545

The reasons for the P1545 OBDII fault code are as follows:

  • The air conditioning clutch relay wiring may have been damaged.
  • The air conditioning clutch relay circuit may be shorted.
  • The A/C clutch relay may be faulty.

Possible solutions of the DTC code P1545

The steps to follow to correct the DTC P1545 OBD2 code are:

  • Consult the TSBs.
  • Using a scan tool, command the A/C relay by turning it on and off in the Engine Output Controls list. You should hear a click as you turn the relay on for each command sent to it. If not, check the condition of its wires and connectors. Repair as necessary.
  • Check the voltage and ground signal on the switch side of the A/C compressor clutch relay. If the results show that there is a short circuit, make repairs as necessary.
  • If no damage to the circuit connections is found, suspect a bad relay and replace it.

Codes related to P1545

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