Cruze

DTC P244B

The diesel exhaust after-treatment system consists of an under bonnet pre-catalytic converter and an underbody catalytic converter. The underbody catalytic converter also consists of the main diesel oxidation catalyst and the coated diesel particulate filter. One of the main purposes of the diesel particulate filter is to collect particulates from the engine exhaust in order to minimise discharge of soot to the atmosphere. The soot particles accumulate in the channels of the diesel particulate filter and are burned off at regular intervals, through a process called regeneration. This prevents the diesel particulate filter from clogging. The ECM commands the diesel particulate filter regeneration after calculating various vehicle conditions such as diesel particulate filter pressure difference, exhaust gas temperature, engine oil quality, engine speed, etc. Excessive accumulation of the soot in the diesel particulate filter 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 diesel particulate filter temperature is raised to approximately 600°C (1112°F) and the accumulated soot is oxidised or burned off into carbon dioxide (CO2).

The diesel particulate filter pressure sensor is connected to the diesel particulate filter by pressure pipes. The diesel particulate filter pressure sensor measures the level of soot deposit in the diesel particulate filter and protects the engine by triggering regeneration when critical soot level is detected in the filter.

The ECM detects the diesel particulate filter differential pressure sensor signal is greater than 90 kPa (13 PSI) for greater than 1 s.

DTC P244B is a Type A DTC.

DTC P244B is a Type A DTC.

Schematic Reference

Engine Controls Schematics : LLW

Connector End View Reference

Component Connector End Views

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the DTC information with a scan tool. Verify that no other DTCs are set.

⇒	If any other DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

2. Engine idling, observe the scan tool diesel particulate filter differential sensor parameter. The reading should be within 0-10 kPa (0-1.5 PSI).
3. 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 are captured in the Freeze Frame/Failure Records Data List.

Note: Observe the scan tool distance since last Diesel Particulate Filter regeneration data parameter. Do Not perform a Diesel Particulate Filter regeneration if it has been performed recently.

⇒	If not within the specified range, perform a Diesel Particulate Filter regeneration.

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.

1. Ignition OFF, inspect for the following:

•	Inlet system/charge air hoses for leaks/restrictions

•	Exhaust system/turbo charger for leaks/restrictions

•	Air filter for restrictions

⇒	If a condition is found, repair as necessary.

2. Ignition OFF, inspect the hose/pipes to the Diesel Particulate Filter Pressure Sensor for leaks, or restrictions.

⇒	If a condition is found, repair as necessary.

3. Ignition OFF, disconnect the harness connector at the B154 Diesel Particulate Filter Pressure Sensor.
4. Test for less than 5 Ω between the low reference circuit terminal 2 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 K20 Engine Control Module.

5. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal 1 and ground.

⇒	If less than the specified range, test the 5 V reference circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

⇒	If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

6. Verify the scan tool DPF differential pressure sensor voltage parameter is greater than 4.8 V.

⇒	If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the K20 Engine Control Module.

7. Install a 1 A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool DPF differential pressure sensor voltage parameter is less than 0.5 V.

⇒	If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

8. Ignition OFF, connect the harness connector at the B154 Diesel Particulate Filter Pressure Sensor.
9. Ignition ON, verify the scan tool DPF differential pressure sensor parameter is between 0.45-0.55 V.

⇒	If not within the specified range, replace the B154 Diesel Particulate Filter Pressure Sensor.

10. If all circuits test normal, replace the B154 Diesel Particulate Filter Pressure Sensor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.