DTC P244A or P244B (LPL or LPV)
Diagnostic Instructions
DTC Descriptors
| DTC P244A 00: Diesel Particulate Filter (DPF)
Low Differential Pressure |
| DTC P244B 00: Diesel Particulate Filter (DPF)
High Differential Pressure |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
5V Reference
|
P0641
|
P244A 00
|
P0641
|
-
|
Signal
|
P244A 00
|
P244B 00
|
P244B 00
|
-
|
Low Reference
|
-
|
P244B 00
|
-
|
-
|
|
| |
Circuit/System Description
The diesel exhaust aftertreatment system consists of an under
hood precatalytic converter and an underbody catalyst. The
underbody catalyst 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 minimize 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 (1 112°F) and the accumulated soot is oxidized or
burned off into carbon dioxide (CO2).
Conditions for Running the DTC
| • |
The ignition is ON, or the
engine is running. |
| • |
The DTCs run continuously when
the above condition is met. |
Conditions for Setting the DTC
P244A
The ECM detects an open circuit or a short to ground greater than 2
s.
P244B
The ECM detects the DPF differential pressure sensor signal is
greater than 4.9 V for greater than 1 s.
Action Taken When the DTC Sets
DTCs P244A and P244B are Type C DTCs.
Conditions for Clearing the DTC
DTCs P244A and P244B are Type C DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exhaust Particulate Filter System Description
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Engine idling, observe the
scan tool diesel particulate filter data parameter. The reading
should be within 0-10 kPa (0-1.5 PSI). |
| 2. |
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
| 1. |
Ignition OFF, disconnect the
harness connector at the B154 Diesel Particulate Filter Exhaust
Differential Pressure Sensor. |
| 2. |
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. |
| 3. |
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 V
reference circuit for a short to voltage. If the circuit tests
normal, replace the K20 Engine Control Module. |
| 4. |
Verify the scan tool DPF
Differential Pressure Sensor 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. |
| 5. |
Install a 1 A fused jumper
wire between the signal circuit terminal 3 and ground. Verify the
scan tool DPF differential pressure sensor 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. |
| 6. |
If all circuits test normal,
replace the B154 Diesel Particulate Filter Exhaust Differential
Pressure Sensor. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
|
