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Home >> GMC >> 2021 >> Terrain SLT, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 95 (Image Display Cameras) >> Diagnostic Information and Procedures >> DTC B399C >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2020 GMC Terrain and 2020 Chevrolet Equinox. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: X4 @ K157 Video Processing Control Module
  3. Wait for greater than 5 s.
  4. Connect appropriate EL-52552pinout tool to K157 Video Processing Control Module
  5. Ignition - On / Vehicle - In Service Mode
  6. Test for 7 to 11 V between the test points: Signal circuit terminal 1-TN @ K157 Video Processing Control Module & Ground (component side)
    • If not between 7 and 11 V 

      Replace the component: K157 Video Processing Control Module

    • Go to next step: If between 7 and 11 V 
  7. Ignition/Vehicle & All vehicle systems - Off
  8. NOTE:

    Before testing the coax cable, check the cable's exterior for being pinched, cut, damaged, or having loose connections at the components, all of which can cause reception issues.

  9. Disconnect the electrical connector: B225L Sideview Camera - Left
  10. Locate the appropriate pinout adapter and load test loop adapter from EL-52552 COAX FAKRA Cable Adaptor Kit.
  11. Connect the 2 adapters together, measure and record the resistance between the terminals at the pinout adapter.
  12. Disconnect the 2 adapters and connect each one to the appropriate end of the coax cable.
  13. At the pinout adapter test terminals, measure the total resistance of the coax cable loop including the connected load test adapter.
    • If not within 5 Ω of the reading from step 10. 

      Replace the coax cable

    • Go to next step: If within 5 Ω of the reading from step 10. 
  14. NOTE:

    If the condition is intermittent or cannot be duplicated, disconnect the connectors and add dielectric grease or lubricant (Nyogel 760G or equivalent, meeting GM specification 9986087). This procedure will correct the high resistance condition due to terminal fretting corrosion.

  15. Replace the component: B225L Sideview Camera - Left
  16. Apply the parking brake.
  17. Engine Running Transmission in Reverse
  18. Verify DTC B399C is not set.
    • If the DTC is set 

      Replace the component: K157 Video Processing Control Module

    • Go to next step: If the DTC is not set 
  19. All OK.