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AutoCodes - Generic - P0688

P0688 Code - Electronic Control Module Power Relay Sense Circuit/Open

- Code Popularity: 25,525 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P0688?

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 P0688?

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.

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0688 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 P0688 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 P0688 - Electronic Control Module Power Relay Sense Circuit/Open - AutoCodes.com
P0688 Code - Electronic Control Module Power Relay Sense Circuit/Open

Need More Information on the Code?

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Information for Specific Makes

  • P0688 Audi Electronic Control Module Power Relay Control Circuit Open
  • P0688 Buick Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Cadillac Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Chevrolet Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Chrysler Auto Shutdown Relay Control Circuit Open
  • P0688 Dodge Auto Shutdown Relay Control Circuit Open
  • P0688 Ford Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 GMC Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Jeep Auto Shutdown Relay Control Circuit Open
  • P0688 Lincoln Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Mercury Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Mitsubishi Electronic Control Module Power Relay Control Circuit Open
  • P0688 Pontiac Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Saturn Electronic Control Module Power Relay Sense Circuit/Open
  • P0688 Volkswagen Electronic Control Module Power Relay Control Circuit Open

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