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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 99 (HVAC - Automatic) >> Diagnostic Information and Procedures >> DTC B3933 >> 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 10 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:B39 A/C Evaporator Temperature Sensor
  3. Test for less than 10 ohms between the test points:Low Reference circuit terminal B & Ground
    • If 10 ohms or greater 
    1. Disconnect the electrical connector:K33 HVAC Control Module
    2. Test for less than 2 ohms between the test points:Low Reference circuit terminal B @ Component harness & Terminal 9 X3 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K33 HVAC Control Module
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 4.8 to 5.2 V between the test points:Signal circuit terminal A & Ground
    • If 4.8 V or less
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:K33 HVAC Control Module
    3. Test for infinite resistance between the test points:Signal circuit terminal A @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    4. Test for less than 2 ohms between the test points:Signal circuit terminal A @ Component harness & Terminal 20 X3 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component:K33 HVAC Control Module
    • If 5.2 V or greater
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector:K33 HVAC Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:Signal circuit terminal A @ Component harness & Ground
    • If 1 V or greater - Repair the short to voltage on the circuit.
    • If less than 1 V - Replace the component:K33 HVAC Control Module
    • Go to next step: If between 4.8 and 5.2 V 
  6. Replace the component:B39 A/C Evaporator Temperature Sensor
  7. Operate the vehicle within the Conditions for Running the DTC.
  8. Verify the DTC does not set.
    • If the DTC sets 

      Replace the component:K33 HVAC Control Module

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