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Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 325 (HVAC System - Automatic) >> Diagnostic Information and Procedures >> DTC B0173, B0178, B0509, B0514, B0519, B3583, or B3933: Air Temperature Sensor >> Circuit/System Testing

Circuit/System Testing

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B3933

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal listed below and ground:
    • Front duct and A/C evaporator temperature sensors- terminal 2
    • Auxiliary duct temperature sensors (with C69) - terminal B
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K33 HVAC Control Module.
    • If less than 10 Ω 
  3. Test for 4.8-5.2 V between the signal circuit terminal listed below and ground.
    • Front duct and A/C evaporator temperature sensors- terminal 1
    • Auxiliary duct temperature sensors (with C69) - terminal A
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
    2. Test for infinite resistance between the signal circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    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 K33 HVAC Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K33 HVAC Control Module.
    • If between 4.8-5.2 V 
  4. Test or replace the temperature sensor.
  5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
  6. Verify the DTC does not set.
    • If the DTC sets 

      Replace the K33 HVAC Control Module.

    • If the DTC does not set 
  7. All OK

B0173, B0178, B0509, B0514, B0519, or B3583

  1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between the low reference circuit terminal listed below and ground:
    • Front duct and A/C evaporator temperature sensors- terminal 2
    • Auxiliary duct temperature sensors (with C69) - terminal B
    • If 10 Ω or greater 
    1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
    2. Test for less than 2 Ω in the low reference circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K33 HVAC Control Module.
    • If less than 10 Ω 
  3. Ignition ON.
  4. Verify the appropriate scan tool Temperature Sensor parameter is less than -37°C (-35°F)
    • If greater than -37°C (-35°F) 
    1. Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
    2. Test for infinite resistance between the signal circuit terminal listed below and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K33 HVAC Control Module.
    • If -37°C (-35°F) or less 
  5. Install a 3 A fused jumper wire between the appropriate signal circuit terminal and the low reference circuit terminal listed below:
    • Front duct and A/C evaporator temperature sensors- signal circuit terminal 1 and low reference terminal 2
    • Auxiliary duct temperature sensors (with C69) - signal circuit terminal A and low reference terminal B
  6. Verify the scan tool temperature sensor parameter is greater than 77°C (170°F).
    • If less than 77°C (170°F) 
    1. Ignition OFF, remove the jumper wire and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
    2. Test for less than 1 V between the signal circuit and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    3. Ignition OFF
    4. 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 K33 HVAC Control Module.
    • If 77°C (170°F) or greater 
  7. Test or replace the temperature sensor.
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