Circuit Description

Ignition voltage is supplied directly to AIR pump relay. PCM controls relay by grounding the control circuit via an internal solid state device called a driver. The primary function of the driver is to supply ground for component being controlled. Each driver has a fault line which is monitored by PCM. When PCM is commanding a component on, voltage of control circuit should be low (about zero volts). When PCM is commanding control circuit to a component off, voltage potential of circuit should be high (near battery voltage). If fault detection circuit senses a voltage other than what is expected, this DTC will set.

DTC will also set when a short to ground, an open circuit or a short to battery voltage is detected on the control circuit, and condition is present for at least 30 seconds.