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Home >> Chevrolet >> 2012 >> Volt >> Repair and Diagnosis >> External Pages >> Different car >> Section 24 (Data Communications System) >> Diagnostic Information and Procedures >> DTC U2401 >> Circuit/System Testing >> Testing the Serial Data Circuits for a Short to Ground
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Testing the Serial Data Circuits for a Short to Ground

WARNING: This page is about a different car, the 2011 Chevrolet Volt. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connectors with the BECM dedicated serial data circuits at another control module that is not communicating, in the direction of the circuit shorted to ground.
  2. Ignition OFF and all vehicle systems OFF, all keys at least 3 meters away from vehicle, all access doors closed. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 1k Ω between each BECM dedicated serial data circuit at the control module connector that was just disconnected and ground. Verify that one or more BECM dedicated serial data circuits are less than 1k Ω.
    • If all BECM dedicated serial data circuits are greater than the specified range, replace the control module that was just disconnected.
  3. Repeat step 1 until one of the follow conditions are isolated:
    • A short to voltage on the BECM dedicated serial data circuit between 2 control modules or splice packs, if equipped.
    • A short to voltage on the BECM dedicated serial data circuit between a control module and a terminating resistor.