1A-296 Engine Control System (4HK1)
DTC P2456 (Flash Code 47)
Circuit Description
The exhaust differential pressure sensor is attached to
the chassis frame near the diesel particulate defuser
(DPD) assembly. The exhaust differential pressure
sensor is a transducer that varies voltage according to
changes of the exhaust gas differential pressure
between in front and in rear of DPD filter.
The ECM learns a variance of the exhaust differential
pressure sensor signal at every ignition cycle after the
ignition switch has been ON with the engine OFF for 30
seconds. (The DPD lamp or “AUTO REGEN.”,
“MANUAL REGEN.” indicators on the instrument panel
cluster indicates this transition by commanded to OFF.)
If the ECM detects that learned exhaust differential
pressure is not within a predetermined range, this DTC
will set.
Condition for Running the DTC
• DTCs P060B, P0697, P2454 and P2455 are not
set.
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
• The engine is stopped.
Condition for Setting the DTC
• The ECM detects that the learned exhaust
differential pressure is not within -4.5 to 4.5 kPa.
Action Taken When the DTC Sets
• The ECM illuminates the MIL when the diagnostic
runs and fails. Refer to DTC Type Definitions for
Action Taken When the DTC Sets - Type A.
• The ECM limits fuel injection quantity.
• The ECM inhibits pilot injection.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the MIL/ DTC - Type A.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
• A skewed exhaust differential pressure sensor
value can set this DTC. The Exhaust Differential
Pressure Sensor on the scan tool should read 0.9
to 1.0 volts with the ignition switch ON and engine
OFF.
Schematic Reference:
Engine Controls Schematics
Connector End View Reference:
Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P2456
Step
Action
Value(s)
Yes
No
1
Did you perform the Diagnostic System Check
- Engine Controls?
—
Go to Step 2
Go to Diagnostic
System Check -
Engine Controls
2
1.
Install a scan tool.
2.
Turn OFF the ignition for 30 seconds.
3.
Start the engine.
4.
Monitor the DTC Information with a scan tool.
Is DTC P2454 or P2455 set?
—
Go to Applicable
DTC
Go to Step 3
3
1.
Turn OFF the ignition for 30 seconds.
2.
Disconnect a ventilation duct from the exhaust
tail pipe if connected.
3.
Turn ON the ignition for 30 seconds while
observing the DTC Information with a scan
tool.
Does the DTC fail this ignition?
—
Go to Step 4
Go to Diagnostic
Aids
LG4HKED-WE-0871.book 296
ページ
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