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P0685 Pontiac Code - Engine Control Module Power Relay Control Circuit Open

- Code Popularity: 1,692 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0685 Pontiac?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • 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
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How to Fix the DTC P0685 Pontiac?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

Check all the Engine Control Module (ECM) fuses, if the fuses are OK, then replacing the ECM relay should take care of the problem.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0685 Pontiac code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

Code P0685 Pontiac Description

The 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.

OBDII Code P0685 Pontiac - Engine Control Module Power Relay Control Circuit Open - AutoCodes.com
P0685 Pontiac Code - Engine Control Module Power Relay Control Circuit Open

Need More Information on the Code?

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Code P0685 Pontiac comments

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