DTC P14A5 or P14A6

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5507260 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 P14A5 Exhaust Gas Recirculation Valve 2 Slow Response - Increasing Flow DTC P14A6 Exhaust Gas Recirculation 2 Slow Response - Decreasing Flow Circuit/System Description For an overview of the component/system, refer to: Exhaust Gas Recirculation (EGR) System Description

Component	Description
K20 Engine Control Module	The control module contains a microprocessor used to process input data to control outputs. 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: The component is actuated by a bidirectional DC motor. 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. Conditions for Running the DTC DTCs related to the following system/component = Not Set – B17 Barometric Pressure Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B130 Exhaust Gas Recirculation Temperature Sensor – B131 Exhaust Temperature Sensor – M122 Exhaust Pressure Regulator Valve – Q17 Fuel Injector No other DTCs related to the concerned component are set. Ambient Air Temperature = Warmer than −20°C (−4°F) Barometric Pressure = Greater than 69.6 kPa (10.1 PSI) Desired EGR Position = Greater than 2% Engine = Running Engine Coolant Temperature = 70 to 129°C (158 to 264°F) Fuel Control Loop Status = Closed Loop Ignition and Start Switch Signal = Greater than 11 V Throttle Position = Greater than 85% Frequency the DTC runs = Continuously — After the running conditions are met Conditions for Setting the DTC Exhaust Gas Recirculation Valve 2 = Low/Insufficient Flow — For greater than 5 s Actions Taken When the DTC Sets DTCs listed in the DTC Descriptor category = Type B Conditions for Clearing the DTC DTCs listed in the DTC Descriptor category = Type B 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

Ignition » On / Vehicle » In Service Mode
Verify there are no DTCs set related to the following component/system: – B17 Barometric Pressure Sensor – B34 Engine Coolant Temperature Sensor – B65 Intake Manifold Pressure and Air Temperature Sensor – B75C Multifunction Intake Air Sensor – B115 Vehicle Speed Sensor – B130 Exhaust Gas Recirculation Temperature Sensor – B131 Exhaust Temperature Sensor – M122 Exhaust Pressure Regulator 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
Verify the condition does not exist: Air Cleaner Element — Saturated with water / Restricted Exhaust Gas Recirculation System — Leaking / Restricted Exhaust System — Leaking / Missing components / Restricted » Refer to: Symptoms - Engine Exhaust Induction System — Leaking / Restricted » Refer to: Component/System Leak Test Q20 Intake Air Flow Valve — Binding or Sticking / Restricted ⇒ If a condition exists Repair or replace as necessary ⇓ If no condition exists
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: Q14B Exhaust Gas Recirculation Valve 2 ⇓ If the DTC does not set
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