Circuit/System Testing

2008 Chevrolet Chevy Express G3500, Van Passenger ExtendedSECTION Circuit/System Testing
WARNING: This page is about a different car, the 2010 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: Component Testing is performed before Circuit Testing when diagnosing wheel speed sensors.
  1. Ignition OFF, disconnect the harness connector at the EBCM.
  2. Ignition ON, test for less than 1 V between the low reference circuit terminals of the appropriate sensor listed below and ground.
    • Left front sensor circuit terminal 27
    • Right front sensor circuit terminal 30
    • Left rear sensor circuit terminal 16
    • Right rear sensor circuit terminal 15
    • If greater than the specified range, test the low reference circuit for a short to voltage.
  3. Test for less than 1 V between the signal circuit terminals of the appropriate sensor listed below and ground.
    • Left front sensor circuit terminal 28
    • Right front sensor circuit terminal 17
    • Left rear sensor circuit terminal 4
    • Right rear sensor circuit terminal 3
    • If greater than the specified range, test the signal circuit for a short to voltage.
  4. Ignition OFF, test for infinite resistance between the low reference terminals of the appropriate sensor listed below and ground.
    • Left front sensor circuit terminal 27
    • Right front sensor circuit terminal 30
    • Left rear sensor circuit terminal 16
    • Right rear sensor circuit terminal 15
    • If less than the specified value, test the low reference circuit for a short to ground.
  5. Test for infinite resistance between the following signal circuit terminals of the appropriate sensor listed below and ground.
    • Left front sensor circuit terminal 28
    • Right front sensor circuit terminal 17
    • Left rear sensor circuit terminal 4
    • Right rear sensor circuit terminal 3
    • If less than the specified value, test the signal circuit for a short to ground.
  6. Ignition OFF, disconnect the harness connector at the wheel speed sensor.
  7. Test for less than 2 Ξ© between the appropriate low reference circuit terminals listed below.
    • Left front sensor circuit terminal 27 at the EBCM harness connector, and terminal B at the wheel speed sensor harness connector
    • Right front sensor circuit terminal 30 at the EBCM harness connector and terminal B at the wheel speed sensor harness connector
    • Left rear sensor circuit terminal 16 at the EBCM harness connector and terminal B at the wheel speed sensor harness connector
    • Right rear sensor circuit terminal 15 at the EBCM harness connector and terminal B at the wheel speed sensor harness connector
    • If greater than the specified range, test the low reference circuit for an open or high resistance.
  8. Test for less than 2 Ξ© between the appropriate signal circuit terminals listed below.
    • Left front sensor circuit terminal 28 at the EBCM harness connector and terminal A at the wheel speed sensor harness connector
    • Right front sensor circuit terminals 17 at the EBCM harness connector and terminal A at the wheel speed sensor harness connector
    • Left rear sensor circuit terminals 4 at the EBCM harness connector and terminal A at the wheel speed sensor harness connector
    • Right rear sensor circuit terminals 3 at the EBCM harness connector and terminal A at the wheel speed sensor harness connector
    • If greater than the specified range, test the signal circuit for an open or high resistance.
  9. If all circuits test normal, test or replace the wheel speed sensor. If the DTC resets, replace the EBCM.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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