Isuzu 2008MY N Series, Руководство по ремонту

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Engine Control System (4HK1) 1A-291
DTC P2454 or P2455 (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 sensor
has the following circuits:
• 5 volts reference circuit
• Low reference circuit
• Exhaust differential pressure sensor signal circuit
The exhaust differential pressure sensor provides a
signal to the ECM on the signal circuit, which is relative
to the differential pressure changes in front and in rear
of DPD filter. The ECM should detect a low signal
voltage at a low differential pressure, such as small PM
accumulation. The ECM should detect high signal
voltage at high differential pressure, such as large PM
accumulation. If the ECM detects an excessively low or
high signal voltage, DTC P2454 or P2455 will set.
Condition for Running the DTC
• DTCs P060B and P0697 are not set.
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that the exhaust differential
pressure sensor signal voltage is less than 0.2
volts. (DTC P2454)
• The ECM detects that the exhaust differential
pressure sensor signal voltage is more than 4.9
volts. (DTC P2455)
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.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P2454
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 P0697 also set?
—
Go to DTC P0697 Go to Step 3
3
Observe the Exhaust Differential Pressure Sensor
parameter with a scan tool.
Is the Exhaust Differential Pressure Sensor
parameter less than the specified value?
0.2 volts
Go to Step 4
Go to Diagnostic
Aids
4
1. Turn OFF the ignition.
2. Disconnect the exhaust differential pressure
sensor harness connector.
3. Connect a DMM between the 5 volts reference
circuit (pin 3 of J-33) and a known good
ground.
4. Turn ON the ignition, with the engine OFF.
Is the DMM voltage more than the specified
value?
4.5 volts
Go to Step 5 Go to Step 6
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