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Tahoe / Yukon Service Manual

DTC P045A, P045D, or P1419-P141C

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5471157 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 P045A Exhaust Gas Recirculation Valve 2 Control Circuit DTC P045D Exhaust Gas Recirculation Valve 2 Control Circuit High DTC P1419 Exhaust Gas Recirculation Valve 2 Supply Voltage Circuit DTC P141A Exhaust Gas Recirculation Valve 2 Control Circuit Shorted DTC P141B Exhaust Gas Recirculation Valve 2 Current Performance DTC P141C Exhaust Gas Recirculation Valve 2 Driver Temperature Too High Diagnostic Fault Information

Circuit Short to Ground Open/High Resistance Short to Voltage Signal Performanc
Control — Terminal 4 P045E P045A P045E —
Control — Terminal 5 — P045E P045E —

Circuit/System Description For an overview of the component/system, refer to: Exhaust Gas Recirculation (EGR) System Description

Circuit Description
Control — Terminal 4 The output circuit is switched from ground to 12 V to activate the component.
Control — Terminal 5 The output circuit is switched from ground to 12 V to activate the component.
Component Description
K20 Engine Control Module The control module contains a microprocessor used to process input data to control outputs.
Component Description
The control module controls a series of actuators to ensure optimal engine performance. The control module does this by reading values from a variety of sensors, interprets the data and adjusts the engine actuators accordingly.
Q14B Exhaust Gas Recirculation Valve 2 The assembly has several functions: Exhaust Gas Recirculation Valve — A solenoid valve is an electro-mechanically operated valve. The valve is controlled by an electric current through the solenoid. EGR Position Sensor — The component contains 1 potentiometer(s) that varies its resistance proportionally with the position of the component/system: EGR Valve

Redirecting the exhaust gas back into the intake system aids in reducing the amount of oxygen that enters the cylinders. This reduces the amount of nitrogen oxide (NOx) that is produced during combustion. The component is actuated by a bidirectional DC motor. Conditions for Running the DTC Engine = Running Ignition Voltage = Greater than 11 V Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC P045A Control Circuit = Open — For greater than 4 s P045D Control Circuit = Short to Voltage — For greater than 4 s P1419 Control Circuit = Low Voltage — For greater than 4 s P141A Control Circuit = Control Circuit Shorted to Control Circuit — For greater than 4 s P141B Exhaust Gas Recirculation Valve 2 = High Current — For greater than 4 s P141C Exhaust Gas Recirculation Valve 2 = High Temperature — For greater than 4 s 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. Perform the scan tool function: » Exhaust Gas Recirculation Valve 2 » Increase Verify the scan tool parameter: Exhaust Gas Recirculation Valve 2 Position Sensor = 0 to 60% and changes ⇒ If not between 0 and 60% or does not change Refer to: Circuit/System Testing ⇓ If between 0 and 60% and changes
  3. 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 Refer to: Circuit/System Testing ⇓ If the DTC is not set
  4. All OK. Circuit/System Testing
  5. Ignition/Vehicle & All vehicle systems » Off
  6. Disconnect the electrical connector: Q14B Exhaust Gas Recirculation Valve 2
  7. Disconnect the electrical connector: K20 Engine Control Module
  8. Ignition » On / Vehicle » In Service Mode
  9. Test for less than 1 V between the test points: Control circuit terminal 4 @ Component harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V
  10. Test for infinite resistance between the test points: Control circuit terminal 4 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance
  11. Test for less than 2 Ω between the test points: Control circuit terminal 4 @ Component harness & Terminal 112 X2 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  12. Test for less than 1 V between the test points: Control circuit terminal 5 @ Component harness & Ground ⇒ If 1 V or greater » Repair the short to voltage on the circuit. ⇓ If less than 1 V
  13. Test for infinite resistance between the test points: Control circuit terminal 5 @ Component harness & Ground ⇒ If less than infinite resistance » Repair the short to ground on the circuit. ⇓ If infinite resistance
  14. Test for less than 2 Ω between the test points: Control circuit terminal 5 @ Component harness & Terminal 111 X2 @ Control module harness ⇒ If 2 Ω or greater » Repair the open/high resistance in the circuit. ⇓ If less than 2 Ω
  15. Replace the component: Q14B Exhaust Gas Recirculation Valve 2
  16. Connect the electrical connector: K20 Engine Control Module
  17. 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: K20 Engine Control Module ⇓ If the DTC is not set
  18. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair: Diagnostic Repair Verification Exhaust Gas Recirculation Valve Replacement - Exhaust Gas Recirculation Cooler For control module replacement, programming, and setup refer to: Control Module References