Circuit Description

WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.

Ignition voltage is supplied directly to the A/C compressor clutch relay. The engine control module (ECM) or powertrain control module (PCM) controls the relay by grounding the A/C compressor clutch relay control circuit via an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. The driver has a fault line which is monitored by the ECM or PCM. When the ECM or PCM is commanding a component ON, the voltage of the control circuit should be near 0 volts. When the ECM or PCM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be near battery voltage. If the fault detection circuit senses a voltage other than what is expected, this DTC will set.

The ECM or PCM will monitor the control circuit for the following:

A short to ground
A short to voltage
An open circuit
An open relay coil
An internally shorted or excessively low resistance relay coil

When the ECM or PCM detects any of the above malfunctions, this DTC is set and the affected driver is disabled.