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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 44 (Lighting System - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC B257A >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE:

    It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.

  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector:S30 Headlamp Switch
  3. Test for less than 10 ohms between the test points:Ground circuit terminal 8 & Ground
    • If 10 ohms or greater 
    1. Test for less than 2 ohms between the test points:Ground circuit terminal 8G @ Component harness & The other end of the circuit GT
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Repair the open/high resistance in the ground connection.
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the scan tool parameter:Automatic Headlamps Disable Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:x1 @ K9 Body Control Module
    3. Test for infinite resistance between the test points:Signal circuit terminal 3 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component:K9 Body Control Module
    • Go to next step: If the specified state 
  6. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 3 & Ground circuit terminal 8
  7. Verify the scan tool parameter:Automatic Headlamps Disable Switch = Active
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector:X1 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Signal circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points:Signal circuit terminal 3A @ Component harness & Terminal 11S @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K9 Body Control Module
    • Go to next step: If the specified state 
  8. Remove - Jumper Wire
  9. Verify the scan tool parameter:Park Lamps Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:X1 @ K9 Body Control Module
    3. Test for infinite resistance between the test points:Signal circuit terminal 5 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component:K9 Body Control Module
      • Go to next step: If the specified state 
  10. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 5 & Ground circuit terminal 8
  11. Verify the scan tool parameter:Park Lamps Switch = Active
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper Wire
    2. Disconnect the electrical connector :x1 @ K9 Body Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Signal circuit terminal 5 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points:Signal circuit terminal 5A @ Component harness & Terminal 22 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K9 Body Control Module
      • Go to next step: If the specified state 
  12. Remove - Jumper Wire
  13. Verify the scan tool parameter:Headlamps On Switch = Inactive
    • If not the specified state 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:X1 @ K9 Body Control Module
    3. Test for infinite resistance between the test points:Signal circuit terminal 1@ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component:K9 Body Control ModuleCC Control Module
      • Go to next step: If the specified state 
  14. Connect a 3 A fused jumper wire between the test points:Signal circuit terminal 1A & Ground circuit terminal 8G
  15. Verify the scan tool parameter:Parameter = Headlamps On Switch Parameter = Active
    • If not the specified state 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the electrical connector:X! @ K9 Body Control ModuleCC Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Signal circuit terminal 1A @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • Go to next step: If less than 1 V
    5. Ignition/Vehicle - Off
    6. Test for less than 2 ohms between the test points:Signal circuit terminal 1A @ Component harness & Terminal 16S @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K9 Body Control ModuleCC Control Module
    • Go to next step: If the specified state 
  16. Test or replace the component:S30 Headlamp Switch
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