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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 165 (Engine Controls And Fuel - 2.7L (L3B) - Diagnostic Information And Procedures (1 Of 3)) >> Diagnostic Information and Procedures >> DTC P0119, P2186, P2BB5, or P2BBA >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT4. 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.
    • For component location, refer to: Repair Instructions
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the appropriate electrical connector:
    • B34A Engine Coolant Temperature Sensor 1
    • B34B Engine Coolant Temperature Sensor 2
    • B34E Engine Coolant Temperature Sensor 5
    • B34F Engine Coolant Temperature Sensor 6
  3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 2 & Ground
    • If 10 ohms or greater 
    1. Disconnect the appropriate electrical connector: K20 Engine Control Module
    2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 2 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K20 Engine Control Module
    • Go to next step: If less than 10 ohms 
  4. Ignition - On / Vehicle - In Service Mode
  5. Verify the appropriate scan tool parameter: Engine Coolant Temperature Sensor or Engine Coolant Temperature Sensor 2, 5, 6 = Colder than -39°C (-38°F)
    • If -39°C (-38°F) or warmer 
    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 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
    • 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 1 & Low Reference circuit terminal 2
  7. Verify the scan tool parameter: Engine Coolant Temperature Sensor or Engine Coolant Temperature Sensor 2, 5, 6 = 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 1 @ 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 1 @ Component harness & The other end of the circuit @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - 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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