P0685 SATURN - Engine Control Module Power Relay Control Circuit Open
- Weak battery
- Low voltage while cranking
- Faulty Engine Control Module (ECM) power relay
- ECM power relay harness is open or shorted
- ECM power relay circuit poor electrical connection
- Blown ECM fuse
- Faulty ECM
Tech notesCheck all the Engine Control Module (ECM) fuses, if the fuses are OK, then replacing the ECM relay should take care of the problem.
- Engine Light ON (or Service Engine Soon Warning Light)
P0685 Saturn DescriptionThe powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The Engine Control Module (ECM) supplies the ground path to the relay coil control circuit via an internal integrated circuit called an Output Driver Module (ODM). The ODM output control is configured to operate as a low side driver for the powertrain relay. The ODM for the powertrain relay also incorporates a fault detection circuit, which is continuously monitored by the ECM. When the ECM commands the powertrain relay ON, ignition 1 voltage is supplied to the ECM, and to several additional circuits.
Need more help?Get the P0685 Saturn code diagnosed by a professional: Find a repair shop in your area
P0685 SATURN CommentsHelp us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the P0685 Saturn code? Have you replaced any parts?
Any information is appreciated. Thanks