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Home >> Cadillac >> 2021 >> CT4 Sport, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 399 (Engine Cooling System - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> DTC P1096-P1098, P10A0, P10A1, P26B7, P26BB, P2DE7, or U0617 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2022 Cadillac CT5. However, it is still accessible from the selected car via links, so may be relevant.

Test 1

    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: Q74 Engine Coolant Bypass Valve @ Q97 Engine Coolant Flow Control Valve
  3. Test for less than 10 ohms between the test points: Low Reference circuit terminal 5 & Ground
    • If 10 ohms or greater 
    1. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module
    2. Test for less than 2 ohms between the test points: Low Reference circuit terminal 5 @ 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. Test for 4.8 to 5.2 V between the test points: 5 V Reference circuit terminal 3 & Low Reference circuit terminal 5
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 3 @ 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: 5 V Reference circuit terminal 3 @ 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
    • If greater than 5.2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 3 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If between 4.8 and 5.2 V 
  6. Test for 4 to 8 V between the test points: Serial Data terminal 4 & Ground
    • If less than 4 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points: Serial Data terminal 4 @ 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: Serial Data terminal 4 @ 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
    • If greater than 8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the appropriate electrical connector: X2 @ K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Serial Data terminal 4 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If between 4 and 8 V 
  7. Test or replace the component: Q74 Engine Coolant Bypass Valve

Test 2

  1. Ignition - On / Vehicle - In Service Mode
  2. Disconnect the electrical connector: Q74 Engine Coolant Bypass Valve
  3. Ignition/Vehicle - Off - For greater than 2 min
  4. Ignition - On / Vehicle - In Service Mode
  5. Test for 12.0 to 13.0 V between the test points:
    • Control circuit terminal 1 @ Component harness & Ground
    • Control circuit terminal 2 @ Component harness & Ground
    • If not the specified value 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X3 @ K20 Engine Control Module
    3. Test for infinite resistance between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control circuit terminal 2 @ 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:
      • Control circuit terminal 1 @ Component harness & The other end of the circuit @ Control module harness
      • Control 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 the specified value 
  6. Perform the scan tool function: Clear DTCs
  7. Wait 5 s before proceeding to the next step.
  8. Test for less than 1.0 V between the test points:
    • Control circuit terminal 1 @ Component harness & Ground
    • Control circuit terminal 2 @ Component harness & Ground
    • If 1 V or greater 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: X3 @ K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • Control circuit terminal 1 @ Component harness & Ground
      • Control circuit terminal 2 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K20 Engine Control Module
    • Go to next step: If less than 1 V 
  9. Test or replace the component: Q74 Engine Coolant Bypass Valve
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