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Home >> Chevrolet >> 2019 >> Sonic LS, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 44 (Lighting System) >> Diagnostic Information And Procedures >> DTC B2645 >> Circuit/System Testing
July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Circuit/System Testing

WARNING: This page is about a different car, the 2018 Chevrolet Sonic. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, open and close drivers door, disconnect the harness connector at the B10 Ambient Light Sensor. It may take up to 2 minutes for all vehicle systems to power down.
  2. Test for less than 15 Ω between the ground circuit terminal 6 and ground.
    • If 15 Ω or greater 
    1. Ignition OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • Go to next step: If less than 15 Ω 
  3. Ignition ON.
  4. Verify the scan tool Ambient Light Sensor parameter is greater than 4.65 V.
    • If 4.65 V or less 
    1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module.
    2. Test for infinite resistance between the signal circuit terminal 5 and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K9 Body Control Module.
    • Go to next step: If greater than 4.65 V 
  5. Install a 3 A fused jumper wire between the signal circuit terminal 5 and the ground circuit terminal 6.
  6. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 V.
    • If 0.196 V or greater 
    1. Ignition OFF, disconnect the X2 harness connector at the K9 Body Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit terminal 5 and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    3. Test for less than 2 Ω in the signal circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • Go to next step: If less than 0.196 V 
  7. Test or replace the B10 Ambient Light Sensor.
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