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:

As soot loading continues to increase, differential pressure increases. When differential pressure exceeds a calibrated threshold, this diagnostic will run and fail.

DTC P244B is a Type A DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Description and Operation

Diesel Particulate Filter (DPF) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Special Tools

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.

⇒	If any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle .

2. Engine running at a warm stabilized idle, observe the scan tool Particulate Filt. Pressure Variance parameter. The value should be between 0-3 kPa.
3. Verify the following scan tool parameters:

•	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 603 kilometers (375 miles) at sea level, or less than 402 kilometers (250 miles) when equal to or above 5,000 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 .

4. Operate the vehicle within the Conditions for Running the DTC to verify the DTC will not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

Important: 

•	Perform the Repair Verification after completing the Circuit/System Testing.

•	Select Capture Info to store the DTC 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:

•	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.

2. Test for water in fuel contamination. Refer to Contaminants-in-Fuel Diagnosis .
3. 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.

⇒	If greater than the specified range, replace the EGR valve and gaskets.

4. Test the air induction system for leaks. Perform the Induction System Smoke Test in Charge Air Cooler Diagnosis .

⇒	If an air leak is found, repair as necessary.

5. Test the charge air cooler (CAC) for leaks. Perform the Full System Air Leak Test in Charge Air Cooler Diagnosis .
6. Test the fuel system for leaking fuel injectors, high fuel pressures, or high fuel injector flow rates. Refer to Fuel Injector Balance Test with Tech 2 .
7. Ignition OFF, disconnect the harness connector at the exhaust differential pressure sensor.
8. Ignition OFF for 90 seconds, test for less than 5 ohms between the low reference circuit terminal 1 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

9. Disconnect the harness connector X1 at the ECM.
10. Test for less than 5 ohms on the DPF differential pressure sensor circuits between the following terminals:

•	ECM X1 5-volt reference circuit terminal 14 to exhaust differential pressure sensor terminal 3.

•	ECM X1 signal circuit terminal 43 to exhaust differential pressure sensor terminal 2.

⇒	If greater than the specified range, repair the affected circuit for an open/high resistance.

11. If all circuits, exhaust system and engine control system components test normal, test or replace the exhaust differential pressure sensor.

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.

Important: You must perform the Repair Verification after completing the 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.

⇒	If the voltage is erratic, replace the differential pressure sensor.

1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Turn OFF the ignition for 90 seconds.
5. Duplicate the Conditions for Running the DTC and use the freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset. If the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List - Vehicle and perform the appropriate diagnostic procedure.

Notice: To avoid internal DPF substrate damage, do not interrupt or terminate a service regeneration when DTC P244B is set.

6. To avoid the customer's return to the service department, perform the Diesel Particulate Filter (DPF) Service Regeneration .

⇒	If DTC P244B resets, or the service regeneration does not complete, replace the exhaust particulate filter and perform the DPF Reset For Replace DPF with a scan tool.