P2459
DTC P2459
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P2459
- Diesel Particulate Filter Regeneration Too Often
Circuit/System Description
The particulates in the exhaust gases are collected by the diesel particulate filter (DPF). When the filter becomes saturated with particulates, the particulates 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 pressure differential 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 pressure differential sensor values
Conditions for Running the DTC
* DTC P0101, P0401, P0402, P2002, P2229, P2453, P2454, or P2455, are not set.
* The engine is running.
* The Intake Air Temperature is warmer than -7°C (19°F)
* The BARO pressure is greater than 75 kPa (11 psi).
* One active regeneration event has completed.
* DTC P2459 runs continuously once a consecutive regeneration is triggered after a regeneration has completed.
Conditions for Setting the DTC
The ECM detects that the actual soot level is greater than an expected soot level when regeneration is triggered.
Action Taken When the DTC Sets
DTC P2459 is a Type B DTC.
Conditions for Clearing the MIL/DTC
DTC P2459 is a Type B DTC.
Diagnostic Aids
* A skewed or shifted exhaust pressure differential sensor (DPS) 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 will cause inaccuracies in the soot model and cause this DTC to set.
* Low engine compression may cause this DTC to set.
* Water in the fuel system will lower the energy of the fuel which lowers the regeneration temperatures and may cause this DTC to set.
* Turbocharger underboost may cause this DTC to set.
* Charge air cooler (CAC) leaks may cause this DTC to set.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation Reference
Exhaust Aftertreatment System Description Exhaust Aftertreatment System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
* J-23738-A - Mityvac
* J-35555 - Metal Mityvac
Circuit/System Verification
1. Ignition On.
2. Verify that DTCs P003A, P0047, P0048, P0088, P0101, P0201-P0208, P0234, P0263, P0266, P0269, P0272, P0275, P0278, P0281, P0284, P0299, P02E0, P02E2, P02E3, P02E7-P02E9, P02EB, P0300-P0308, P0401, P0402, P0420, P046C, P11CC, P144B, P144C, P2032, P2033, P2453-P2455 P24A0 or P24A1 are not set.
• If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle
• If none of the DTCs are set
3. Engine idling at operating temperature, observe the scan tool Particulate Filt. Pressure Variance parameter. The value should be between 0 and +3 kPa.
• If not within the specified range
Refer to Circuit/System Testing.
• If within the specified range
4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
5. Verify DTC P2459 does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
6. All OK.
Circuit/System Testing
1. Engine running, verify the scan tool Particulate Filt. Pressure Variance parameter increases as engine speed is increased.
• If the parameter decreases or does not increase as engine speed is increased
Inspect for incorrect differential pressure line routing
• If the parameter increases as engine speed is increased
2. Verify the following conditions do not exist:
* Water in fuel contamination-Refer to Contaminants-in-Fuel Diagnosis Contaminants-in-Fuel Diagnosis.
* Air induction system leaks-Perform the Induction System Smoke Test in Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).
* CAC leaks-Perform the Full System Air Leak Test and Induction System Smoke Test in Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).
* Exhaust system leaks. An exhaust system leak may cause inaccurate B131 Exhaust Gas Temperature Sensor or B154 Exhaust Pressure Differential Sensor values causing this DTC to set.
* Improperly installed or loose B131 Exhaust Gas Temperature Sensors will cause inaccuracies in the soot model and cause this DTC to set.
* Q57 Indirect fuel injector leaking or restricted-Refer to Exhaust Aftertreatment Fuel Injector Diagnosis Testing and Inspection
* Engine mechanical condition, for example low compression. Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.
• If a condition is found
Repair as necessary
• If no condition is found
3. Inspect the B154 Exhaust Pressure Differential Sensor system for any of the following conditions:
* Modifications
* Damaged components
* A skewed or shifted B154 Exhaust Pressure Differential Sensor. A sensor that is skewed will cause inaccuracies in the soot model and may cause this DTC to set. Refer to Component Testing.
* Loose or improperly installed components.
* Improperly routed differential pressure lines-The B154 Exhaust Pressure Differential Sensor line should have a continuous downward gradient without any sharp bends or kinks from the sensor to the DPF.
* Inspect the flexible part of the B154 Exhaust Pressure Differential Sensor lines for internal restrictions.
• If a condition is found
Repair as necessary
• If no condition is found
4. Ignition ON.
5. 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.
• If not within the specified range
Replace the Q14 Exhaust Gas Recirculation Valve and gaskets.
• If within the specified range
6. Test the charge air cooler (CAC) for leaks. Perform the Full System Air Leak Test and Induction System Smoke Test in Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).
• If a condition is found
Repair as necessary
• If no condition is found
7. Perform Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration
• If the DPF service regeneration aborts during the 2500 RPM phase of the regeneration
Replace the diesel particulate filter.
• IF the DPF service regeneration completes
8. All OK.
Component Testing
Note: You must perform the Circuit/System Testing in order to verify the integrity of the B154 Exhaust Pressure Differential Sensor circuits before proceeding with Component Testing.
1. Ignition OFF.
2. Remove the B154 Exhaust Pressure Differential Sensor.
3. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 3 and the corresponding terminal of the B154 Exhaust Pressure Differential Sensor.
4. Install a jumper wire between the low reference circuit terminal 1 of the B154 Exhaust Pressure Differential Sensor and ground.
5. Connect a DMM between terminal 2 of the B154 Exhaust Pressure Differential Sensor and ground.
6. Ignition ON, with the J-23738-A - Mityvac or J-35555 - Metal Mityvac connected to the B154 Exhaust Pressure Differential Sensor rear pressure port, slowly apply vacuum while monitoring the voltage on the DMM. The voltage should vary and transition smoothly without any spikes or dropouts.
• If the voltage does not vary or transition smoothly
Replace the B154 Exhaust Pressure Differential Sensor.
• If the voltage varies and transitions smoothly
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Exhaust Particulate Filter Replacement (LGH-35 Series) Exhaust Particulate Filter Replacement (35 Series)Exhaust Particulate Filter Replacement (LGH) Exhaust Particulate Filter Replacement
* Exhaust Pressure Differential Sensor Pipe Replacement Exhaust Pressure Differential Sensor Pipe Replacement
* Exhaust Pressure Differential Sensor Replacement Exhaust Pressure Differential Sensor Replacement
* Perform the following scan tool reset procedures:
1. NOx Catalyst Reductant Loading Reset
2. NOx Catalyst Reset
3. DPF/Catalyst 2 Reset
4. Perform the Diesel Particulate Filter (DPF) Regeneration Enable Diesel Particulate Filter (DPF) Regeneration Enable