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Home >> Chevrolet >> 2022 >> Tahoe PPV, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 13 (Engine Controls And Fuel - 3.0L (Lm2) Diesel - Diagnostic Information And Procedures (4 Of 5)) >> Diagnostic Information and Procedures >> DTC P143C, P20C1-P20C4, P221E, or P221F >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: A38 Reductant Pump and Sensor Assembly
  3. Ignition - On / Vehicle - In Service Mode
  4. Test for 2.5 to 4.5 V between the test points: Control circuit terminal 10 & Ground
    • If less than 2.5 V 
    1. Ignition/Vehicle & All vehicle systems - Off
    2. Disconnect the electrical connector: @ K115 Reductant Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 10 @ 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 10 @ Component harness & Terminal 2 @ Control module harness
      • If 2 ohms or greater - Repair the open/high resistance in the circuit.
      • If less than 2 ohms - Replace the component: K115 Reductant Control Module
    • If greater than 4.5 V 
    1. Ignition/Vehicle & All vehicle systems - Off
    2. Disconnect the electrical connector: @ K115 Reductant Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 10 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K115 Reductant Control Module
    • Go to next step: If between 2.5 and 4.5 V 
  5. Connect a test lamp between the test points: Control circuit terminal 15 & B+
  6. Ignition - On / Vehicle - In Service Mode
  7. Verify the test lamp does not turn On.
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: @ K115 Reductant Control Module
    3. Test for infinite resistance between the test points: Control circuit terminal 15 @ Component harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K115 Reductant Control Module
    • Go to next step: If the test lamp does not turn On 
  8. Connect a test lamp between the test points: Control circuit terminal 15 & Ground
  9. Ignition - On / Vehicle - In Service Mode
  10. Verify the test lamp does not turn On.
    • If the test lamp turns On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Disconnect the electrical connector: @ K115 Reductant Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: Control circuit terminal 15 @ Component harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K115 Reductant Control Module
    • Go to next step: If the test lamp does not turn On 
  11. Disconnect the electrical connector: @ K115 Reductant Control Module
  12. Test for less than 2 ohms between the test points: Control circuit terminal 15 @ Component harness & Terminal 14 @ Control module harness
    • If 2 ohms or greater - Repair the open/high resistance in the circuit.
    • Go to next step: If less than 2 ohms
  13. Test or replace the component: A38 Reductant Pump and Sensor Assembly
  14. 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.

    Verify the DTC does not set.

    • If the DTC sets 

      Replace the component: K115 Reductant Control Module

    • Go to next step: If the DTC is not set 
  15. All OK.
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