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Tahoe / Yukon Service Manual

DTC P20E8 or P20E9

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5507568 Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions DTC Descriptor DTC P20E8 Reductant Low Pressure DTC P20E9 Reductant High Pressure Circuit/System Description For an overview of the component/system, refer to: Exhaust Aftertreatment System Description Conditions for Running the DTC DTC P10DA, P10DB, P10F4, P20FF, U2412, U2626 = Not set DTCs related to the following system/component = Not Set – G33 Reductant Pump – B194 Reductant Pressure Sensor Engine = Running Ignition and Start Switch Signal = Greater than 11 V Reductant Fluid Reservoir = Not Frozen Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P20E8 Reductant Pressure = Less than a predefined threshold — For greater than 30 s P20E9 Reductant Pressure = Greater than a predefined threshold — For greater than 4 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type A DTC Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type A DTC Reference Information DTC Type Reference Powertrain Diagnostic Trouble Code (DTC) Type Definitions Scan Tool Reference Control Module References Circuit/System Verification

  1. Ignition » On / Vehicle » In Service Mode
  2. Verify no other DTCs are set. ⇒ If other DTCs are set ⇒ Refer to: Diagnostic Trouble Code (DTC) List - Vehicle ⇓ If no other DTCs are set
  3. Verify the scan tool parameter: Reductant Level = Greater than 20% ⇒ If not the specified state Fill the reductant tank to a minimum of 4 L. ⇓ If the specified state
  4. Perform the scan tool control function: Reductant System Leak Test Verify the scan tool parameter: Reductant Pressure = 450 to 550 kPa (65 to 80 PSI) ⇒ If not between 450 and 550 kPa (65 and 80 PSI) Refer to: Circuit/System Testing ⇓ If between 450 and 550 kPa (65 and 80 PSI)
  5. 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. ⇒ If the DTC sets Refer to: Circuit/System Testing ⇓ If the DTC is not set
  6. All OK. Circuit/System Testing
  7. Verify the condition does not exist: Contamination — Emission Reduction Fluid » Refer to: Contaminants-in-Diesel Exhaust Fluid Diagnosis ⇒ If a condition exists Repair or replace as necessary ⇓ If no condition exists
  8. Perform the scan tool control function: Reductant System Leak Test Verify the condition does not exist: Hoses / Lines — Leaking ⇒ If a condition exists Repair or replace as necessary ⇓ If no condition exists
  9. Remove the component: Q61 Reductant Injector — Leave the reductant line and the electrical connector connected.
  10. Place the injector into a suitable container.
  11. Perform the scan tool control function: Reductant System Leak Test Verify the condition does not exist: Reductant Injector — Leaking ⇒ If a condition exists Replace the component: Q61 Reductant Injector ⇓ If no condition exists
  12. Perform the scan tool control function: Reductant System Leak Test Verify the scan tool parameter: Reductant Pressure = 450 to 550 kPa (65 to 80 PSI) ⇒ If not between 450 and 550 kPa (65 and 80 PSI) Replace the component: A38 Reductant Pump and Sensor Assembly ⇓ If between 450 and 550 kPa (65 and 80 PSI)
  13. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Reductant Fluid Injector Replacement — Q61 Reductant Injector Emission Reduction Fluid Tank Replacement — A38 Reductant Pump and Sensor Assembly For control module replacement, programming, and setup refer to: Control Module References Additional Procedures