Circuit Description

The engine control module (ECM) contains an output driver module (ODM) that controls four devices:

• The A/C relay
• The main relay
• The evaporative emission (EVAP) vent solenoid
• The EVAP purge solenoid

The ODM provides grounded output control of the above devices through separate control circuits. The ODM monitors the voltage level at each of the control circuits when the device is commanded ON or OFF. Each ODM output has an internal feedback circuit that connects to the ECM microprocessor. The ECM monitors voltage through the ignition 1 voltage circuit. Excessive voltage or current may cause damage to the ECM. If the ODM detects excessive current or voltage on an output control circuit, this DTC will set.