GM Service Manual Online
For 1990-2009 cars only

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 provides an overview of each diagnostic category.

DTC Descriptor

DTC P2463: Diesel Particulate Filter Soot Level Accumulation

Circuit/System Description

The particulates in the exhaust gases are collected by the diesel particulate filter (DPF). When the filter becomes saturated with particulates, they are incinerated by a regeneration process. The regeneration process increases the exhaust gas temperature, warming the diesel oxidation catalyst (DOC) first, then warming the DPF. The engine control module (ECM) monitors the system with inputs from two exhaust gas temperature (EGT) sensors 1 and 2 and an exhaust differential pressure sensor.

The ECM will command an active regeneration base on a calculated soot model. The soot model calculations are based on the following information:

    • Distance since last DPF regeneration
    • Fuel used since last DPF regeneration
    • Engine run time since last DPF regeneration
    • Exhaust differential pressure sensor values

If soot loading continues to increase it will eventually exceed a calibrated threshold and cause this diagnostic to run and fail.

Conditions for Running the DTC

    • The ignition is ON.
    • DTC P2463 runs continuously when the above condition is met.

Conditions for Setting the DTC

    • The ECM has determined that the soot level within the DPF has exceeded a calibrated threshold.
    • The condition exists for greater than 5 minutes.

Action Taken When the DTC Sets

    • DTC P2463 is a Type A DTC.
    • The ECM commands the engine control system to operate in Reduced Engine Power mode.
    • A message center or an indicator may display Reduced Engine Power.
    • The DPF regeneration is inhibited.

Conditions for Clearing the MIL/DTC

DTC P2463 is a Type A DTC.

Diagnostic Aids

    • A skewed or shifted exhaust differential pressure sensor will cause inaccuracies in the soot model and may cause this DTC to set.
    • Exhaust leaks in the exhaust system may cause inaccurate gas temperature sensor or exhaust differential pressure values causing this DTC to set.
    • Improperly installed or loose exhaust gas temperature (EGT) sensors 1 and 2 will cause inaccuracies in the soot model and cause this DTC to set.
    • Low engine compression may cause this DTC to set.
    • Corroded fuel injectors will have an inability to properly control regeneration temperatures and may cause this DTC to set.
    • Water in the fuel system will lower the energy of the fuel. Emulsified fuel will lower regeneration temperatures that may cause this DTC to set.
    • Operating the vehicle at slower speeds or stop and go conditions will lower the regeneration temperatures. Lower regeneration temperatures will not properly clean the DPF and may cause this DTC to set.
    • Extended operation of the vehicle with Clean Exhaust Filter message may cause this DTC to set.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation Reference

Diesel Particulate Filter (DPF) System Description

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

Special Tools

    • J 23738-A Mityvac
    • J 35555 Metal Mityvac

Circuit/System Verification

  1. Verify that DTCs P003A, P0047, P0048, P0087, P0101, P0201-P0208, P02A1, P02A5, P02A9, P02AD, P02B1, P02B5, P02B9, P02E0, P02E7-P02E9, P029D, P0234, P0299, P0300-P0308, P0401, P0402, P046C, P0545, P0546, P0698, P0699, P2032, P2033, P2269, P2453, or P2563 are not set.
  2. If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  3. Engine running at a warm stabilized idle, observe the scan tool Particulate Filt. Pressure Variance parameter. The value should be between 0-3 kPa.
  4. Verify the following scan tool parameters:
  5. • Engine Run Time Since Last DPF Regeneration parameter--The value should be less than 17.5 hours.
    • Fuel Used Since Last DPF Regeneration parameter--The value should be less than 213 liters (57 gallons).
    • Distance Since Last DPF Regeneration parameter--The value should be less than 604 kilometers (375 miles) at sea level, or less than 402 kilometers (250 miles) when equal to or above 10,000 feet altitude.
         ⇒If any of the parameters are greater than the specified range, perform a DPF Service Regeneration. Refer to Diesel Particulate Filter (DPF) Service Regeneration.
  6. 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.

Circuit/System Testing

    Important: 

       • Perform the Repair Verification after completing the Circuit/System Testing.
       • Select Capture Info to store information with the scan tool.
       • This DTC may require reviewing the Freeze Frame/Failure Records carefully for accurate diagnosis.

  1. Visually inspect the exhaust differential pressure system for any of the following conditions:
  2. • Modifications
    • Damaged components
    • Bends or kinks
    • Loose or improperly installed components--Ensure the smaller diameter pressure line is connected to the front of the DPF and to the smaller port of the differential pressure sensor.
    • Improperly routed differential pressure lines--The exhaust differential pressure line should have a continuous downward gradient from the sensor.
  3. Test for water in fuel contamination. Refer to Contaminants-in-Fuel Diagnosis.
  4. Remove and visually inspect the flexible part of the exhaust differential pressure lines for internal restrictions.
  5. If a condition is found, replace the exhaust differential pressure lines.
  6. Ignition ON, observe the scan tool EGR Position Sensor and Desired EGR Position parameters while commanding the EGR solenoid to 20 percent and 0 percent. The values should remain equal to or less than 3 percent of each other.
  7. If greater than the specified range, replace the EGR valve and gaskets.
  8. Test the air induction system for leaks. Perform the Induction System Smoke Test in Charge Air Cooler Diagnosis.
  9. If an air leak is found, replace the EGR valve gaskets or EGR cooler gasket.
  10. Test the charge air cooler (CAC) for leaks. Perform the Full System Air Leak Test in Charge Air Cooler Diagnosis.
  11. Test the fuel system for leaking, restricted or sticking fuel injectors, high fuel pressures, or high fuel injector flow rates. Refer to Fuel Injector Balance Test with Tech 2.
  12. Ignition OFF, disconnect the harness connector at the exhaust differential pressure sensor.
  13. Ignition OFF and scan tool disconnected for 90 seconds, test for less than 5 ohms between the low reference circuit terminal 1 and ground.
  14. If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  15. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
  16. If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  17. Verify the scan tool Particulate Filter Pressure Variance parameter is greater than 98 kPa.
  18. If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the ECM.
  19. Install a 3A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Particulate Filter Pressure Variance parameter is less than 13 kPa.
  20. If greater than the specified range, test the signal circuit terminal 2 for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  21. If all circuits, the exhaust system, and engine control system components test normal, test the exhaust differential pressure sensor. Refer to Component Testing.

Component Testing

Important: You must perform the Circuit/System Testing in order to verify the integrity of the exhaust differential pressure sensor circuits before proceeding with Component Testing.

  1. Ignition OFF, remove the exhaust pressure differential pressure sensor.
  2. Install a 3A fused jumper wire between the 5-volt reference circuit terminal 3 and the corresponding terminal of the differential sensor. Install a jumper wire between the low reference terminal 1 of the sensor and ground.
  3. Connect a DMM between terminal 2 of the differential sensor and ground.
  4. Ignition ON, with the J 23738-A or J 35555 connected to the pressure sensor rear pressure port, slowly apply vacuum to the sensor while monitoring the voltage. The voltage should vary and transition smoothly without any spikes or dropouts.
  5. If the voltage is erratic, replace the differential sensor.
  6. If the sensor tests normal, perform the Diesel Particulate Filter (DPF) Service Regeneration.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Diesel Particulate Filter (DPF) Service Regeneration
    •  Exhaust Particulate Filter Replacement
    •  Exhaust Pressure Differential Sensor Pipe Replacement
    •  Exhaust Pressure Differential Sensor Replacement