LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2018 >> Acadia Denali, FWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 171 (Instrument Panel System Displays And Gauges) >> Diagnostic Information and Procedures >> DTC P0071-P0074: Ambient Air Temperature Sensor >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Cadillac ATS. 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: B9 Ambient Air Temperature Sensor
  3. Test for less than 10 Ω between the test points: Low Reference circuit terminal B or 2 & Ground
    • If 10 Ω or greater 
    1. Disconnect the electrical connector: K20 Engine Control Module
    2. Test for less than 2 Ω between the test points: Low Reference circuit terminal B or 2 @ Component harness & the other end of the circuit
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the component: K20 Engine Control Module
    • If less than 10 Ω 
  4. Ignition On/Vehicle In Service Mode
  5. Verify the scan tool parameter: Ambient Air Temperature = Less than -34°C (-30°F)
    • If -34°C (-30°F) or warmer 
    1. Ignition/Vehicle Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points: Signal circuit terminal A or 1 @ Component harness & Ground
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the component: K20 Engine Control Module
    • If -35°C (-31°F) or colder 
  6. Connect a 3 A fused jumper wire between the test points: Signal circuit terminal A or 1 & Low Reference circuit terminal B or 2
  7. Verify the scan tool parameter: Ambient Air Temperature = Greater than 143°C (290°F)
    • If 143°C (290°F) or colder 
    1. Ignition/Vehicle Off & Remove Jumper wire(s)
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Ignition On/Vehicle In Service Mode
    4. Test for less than 1 V between the test points: Signal circuit @ Component harness & Ground
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V
    5. Ignition/Vehicle Off
    6. Test for less than 2 Ω between the test points: Signal circuit @ Component harness & the other end of the circuit
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the component: K20 Engine Control Module
    • If 144°C (291°F) or warmer 
  8. Test or replace the component: B9 Ambient Air Temperature Sensor
scientia non olet · About LEMON Manuals