P1545 - FAULT CODE - OBD2
P1545 Code failures by brands
P1545 BUICK, CADILLAC, CHEVROLET, GMC: A/C CLUTCH RELAY CONTROL CIRCUIT
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.