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Home >> Chevrolet >> 2018 >> Suburban 3500 HD LT >> Repair and Diagnosis >> External Pages >> Different car >> Section 2 (Engine Controls And Fuel - 5.3L (L83) Or 6.2L (L86) - DTC P0010 To DTC P0442) >> Diagnostic Information And Procedures >> DTC P0117, P0118 Or P0119: Engine Coolant Temperature (ECT) Sensor Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle & All vehicle systems - Off
    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.
  2. Disconnect the electrical connector : B34 Engine Coolant Temperature Sensor
  3. Test for less than 10 Ω between the test points : Low Reference circuit terminal 1/A & Ground
    • If 10 Ω or greater 
    1. Disconnect the appropriate electrical connector : K20 Engine Control Module
    2. Test for less than 2 Ω between the test points : Low Reference circuit terminal 1/A @ Component harness & The other end of the circuit@Control module harness
      • 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
    • Go to next step : If less than 10 Ω 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the scan tool parameter : ECT Sensor = Colder than -39°C (-38°F)
    • If warmer than -39°C (-38°F) 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector : K20 Engine Control Module
    3. Test for infinite resistance between the test points : Signal circuit terminal 2/B @ 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
    • Go to next step : If colder than -39°C (-38°F) 
  6. Connect a 3 A fused jumper wire between the test points : Signal circuit terminal 2/B & Low Reference circuit terminal 1/A
  7. Verify the scan tool parameter : ECT Sensor = Warmer than 139°C (282°F)
    • If 139°C (282°F) or colder 
    1. Ignition/Vehicle - Off & Remove - Jumper wire(s)
    2. Disconnect the appropriate 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 terminal 2/B @ 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 terminal 2/B @ Component harness & The other end of the circuit @ Control module harness
      • 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
    • Go to next step : If warmer than 139°C (282°F) 
  8. Test or replace the component : B34 Engine Coolant Temperature Sensor
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