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Tahoe / Yukon Service Manual

DTC P144E or P144F

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5507257 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 P144E Closed Loop Particulate Filter Regeneration Control At Limit - Stage 2 Low Temperature DTC P144F Closed Loop Particulate Filter Regeneration Control At Limit - Stage 2 Temperature Too High Circuit/System Description For an overview of the component/system, refer to: Exhaust Aftertreatment System Description Conditions for Running the DTC DTCs related to the following system/component = Not Set – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B131 Exhaust Temperature Sensor – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector Ignition and Start Switch Signal = Greater than 11 V Particulate Filter Regeneration Status = Active Vehicle Speed = Greater than 0 km/h (0 MPH) Frequency the DTC runs = Continuously After the running conditions are met Conditions for Setting the DTC Exhaust Gas Temperature = Not within a calibrated range Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B DTC . Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B DTC . Reference Information Schematic Reference Engine Controls Schematics Connector End View Reference Master Electrical Component List Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs 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 there are no DTCs set related to the following component/system: – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B131 Exhaust Temperature Sensor – Q14 Exhaust Gas Recirculation Valve – Q17 Fuel Injector ⇒ If a related DTC is set Refer to: Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If a related DTC is not set
  3. Ignition/Vehicle » Off
  4. Disconnect the electrical connector: B131A Exhaust Temperature Sensor 1 & B131B Exhaust Temperature Sensor 2
  5. Test the resistance between the test points: Signal terminal 1 & Low Reference terminal 2
  6. Verify the value is within the range listed in the table: Temperature Versus Resistance ⇒ If not in the specified range Replace the appropriate component: B131 Exhaust Temperature Sensor ⇓ If in the specified range
  7. Verify the following conditions do not exist: Air Cleaner Element — Missing / Restricted Exhaust System — Leaking / Restricted » Refer to: Exhaust Leakage or Restricted Exhaust Induction System — Leaking / Restricted » Refer to: Charge Air Cooler Diagnosis ⇒ If a condition exists ⇓ If no condition exists
  8. Perform the scan tool function: Particulate Filter Service Regeneration.
  9. Verify sensor 2 is at least 100°C (180°F) warmer than sensor 1: Exhaust Gas Temperature Sensor Exhaust Gas Temperature Sensor 2 ⇒ If sensor 2 is not at least 100°C (180°F) warmer than sensor 1 Replace the component: Catalytic Converter ⇓ If sensor 2 is at least 100°C (180°F) warmer than sensor 1
  10. 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: Catalytic Converter ⇓ If the DTC does not set
  11. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Nitrogen Oxides Catalytic Converter with Filter Replacement Additional Procedures Perform the scan tool configuration/reset function: Catalyst Reset — Perform only when the following component/system is replaced or serviced: Catalytic Converter