DTC P244C
Diagnostic Instructions
DTC Descriptor
DTC P244C 00: Catalyst Low Temperature During Regeneration Malfunction
Circuit/System Description
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 (DPF). One of the main purposes of the DPF 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 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 (112°F) and the accumulated soot is oxidised or burned off into carbon dioxide (CO2).
Conditions for Running the DTC
The DTC runs during the DPF regeneration process.
Conditions for Setting the DTC
The actual temperature of the exhaust gas temperature sensor 2 is 125°C (257°F) less than the desired temperature.
Action Taken When the DTC Sets
DTC P244C is a Type A DTC.
Conditions for Clearing the DTC
DTC P244C is a Type A DTC.
Diagnostic Aids
• | If the engine has sat overnight, both Exhaust Gas Temperature sensors and the Engine Coolant Temperature (ECT) sensor values should display within 3°C (5°F). |
• | After starting a cold engine, the Exhaust Gas Temperature sensors temperature should rise steadily, then stabilise. |
• | High resistance in the circuits of either of the Exhaust Gas Temperature sensors could set a DTC. |
Reference Information
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
Circuit/System Verification
- Ignition On, observe the DTC information with a scan tool. Verify no other DTCs are set.
- Engine running, perform a regeneration procedure with a scan tool. Observe the DTC information with a scan tool. DTCs P244C should not set.
- 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.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate B131 Exhaust Temperature Sensor.
- 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. |
- Ignition ON, verify the scan tool exhaust gas temperature sensor parameter is at 5 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. |
Note: If the fuse in the jumper wire opens, the signal circuit is shorted to a voltage and the sensor may be damaged.
- Install a 1 A fused jumper wire between the signal circuit terminal 1 and ground. Verify the scan tool exhaust gas temperature sensor parameter is at 0 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. |
- Inspect for the following conditions:
• | Intake and exhaust system for leaks or restrictions |
• | Fuel system for leaks or restrictions |
• | Excessive water in fuel |
• | Exhaust Gas Recirculation (EGR) Valve for normal operation |
• | An engine mechanical condition |
⇒ | If a condition is found, repair as necessary. |
- If all circuits test normal, test or replace the B131 Exhaust Temperature Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Repair Verification
Ignition ON, observe the scan tool DPF accumulated soot mass parameter. The parameter should be less than 70%.
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