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Tahoe / Yukon Service Manual

DTC P200C

Engine Controls and Fuel - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 5507529 Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provide an overview of each diagnostic category. DTC Descriptor DTC P200C Particulate Filter Temperature Too High Circuit/System Description The diesel exhaust aftertreatment system consists of an under hood pre-catalyst and an underbody catalyst. The underbody catalyst also consists of the main diesel oxidation catalyst and the coated Diesel Particulate Filter (DPF). One of the main purposes of the DPF is to collect particulates from the engine exhaust in order to minimize discharge of soot to the atmosphere. The soot particles accumulate in the channels of the DPF and are burned off at regular intervals through a process called regeneration. This prevents the DPF from clogging. The ECM commands the DPF regeneration after calculating various vehicle conditions such as DPF pressure difference, exhaust gas temperature, engine oil quality, engine speed, etc. Excessive accumulation of the soot in the DPF can cause a drop in the engine performance. During regeneration, additional fuel is injected via multiple post injections in order to increase the exhaust gas temperature. During this period, the DPF temperature is raised to approximately 600°C (1 112°F) and the accumulated soot is oxidized or burned off into carbon dioxide (CO2). Conditions for Running the DTC DTCs related to the following system/component = Not Set B131 Exhaust Temperature Sensor Engine = Ignition and Start Switch Signal = If greater than 11 V The DTC runs continuously when the above conditions are met. Conditions for Setting the DTC The ECM detects that the exhaust gas temperature at exhaust gas temperature sensor 2 is greater than 850°C (1,562°F) for greater than 12 s. Action Taken When the DTC Sets DTC P200C is a Type A DTC. DPF regeneration is inhibited The cooling fans are activated Engine power is reduced The engine is shut down when exhaust gas temperature is above a calibrated threshold Conditions for Clearing the DTC DTC P200C is a Type A DTC. Diagnostic Aids After starting the engine, the exhaust gas temperature sensor temperature should rise steadily, then stabilize after the engine reaches operating temperature. If the vehicle has set overnight, the exhaust gas temperature sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F). The following conditions can also cause the DTC to set: Faulty or plugged exhaust system, such as plugged diesel particulate filter Damaged turbocharger Inefficient diesel oxidation catalyst Engine misfire with excessive oil consumption Leaking fuel injectors Incorrect fuel rail pressure Leaks in the intake system and charge air system 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 for scan tool information Circuit/System Verification

  1. Ignition On.
  2. Verify there are no DTCs set related to the following component/system: B9 Ambient Air Temperature Sensor 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 B131B Exhaust Temperature Sensor 2 B136 Exhaust Particulate Matter Sensor B195A Nitrogen Oxides Sensor 1 Q14 Exhaust Gas Recirculation Valve Q17 Fuel Injector ⇒ If a related DTC is set Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis. ⇓ If a related DTC is not set
  3. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions identified from the Freeze Frame/Failure Records data.
  4. Verify DTC P200C is not set. ⇒ If the DTC is set Refer to Circuit/System Testing. ⇓ If the DTC is not set
  5. All OK. Circuit/System Testing
  1. Verify none of the conditions listed below exist: Leaking fuel injectors. Refer to Cylinder Power Balance Test. Engine oil consumption. Refer to Oil Consumption Diagnosis. Incorrect fuel rail pressure. Refer to Fuel System Diagnosis Damaged, missing, or improperly installed exhaust system components. Restrictions in the exhaust pressure differential sensor ports Damaged, bent, restricted, or kinked exhaust pressure differential sensor lines Leaks in the Induction system or charge air system Missing or disconnected charge air system components Presence of additional washers under fuel injectors Turbocharger underboost ⇒ If any condition is found Repair as necessary ⇓ If no condition is found
  2. Perform the Diesel Particulate Filter Service Regeneration.
  3. Verify the regeneration completed. ⇒ If the regeneration did not complete Replace the diesel particulate filter. ⇓ If the regeneration completed
  4. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Nitrogen Oxides Catalytic Converter with Filter Replacement Perform the scan tool DPF/Catalyst 2 Reset after replacing the exhaust particulate filter.