Isuzu 2008MY N Series, Руководство по ремонту

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Engine Control System (4HK1) 1A-71
DTC P0079 or P0080 (Flash Code 38)
Circuit Description
The ECM controls the exhaust throttle solenoid valve
based on the diesel particulate defuser (DPD) system
regeneration status. The exhaust throttle solenoid
energizes to apply vacuum pressure to the diaphragm
chamber to operate exhaust throttle valve that is
installed rear of the DPD housing. If the ECM detects
an improper voltage level on the exhaust throttle
solenoid valve control circuit, DTC P0079 or P0080 will
set.
Condition for Running the DTC
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects a low voltage condition on the
exhaust throttle solenoid control circuit for longer
than 3 seconds when the solenoid is commanded
OFF. (DTC P0079)
• The ECM detects a high voltage condition on the
exhaust throttle solenoid control circuit for longer
than 3 seconds when the solenoid is commanded
ON. (DTC P0080)
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.
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.
Test Description
The number below refers to the step number on the
Circuit/ System Testing.
DTC P0080
3. If the exhaust throttle solenoid valve control circuit
between the ECM and the relay is normal, voltage level
low DTC P0079 will set.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P0079
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. Turn ON the ignition, with the engine OFF.
4. Monitor the DTC Information with a scan tool.
Does the DTC fail this ignition?
—
Go to Step 3
Go to Diagnostic
Aids
3
1. Turn OFF the ignition.
2. Disconnect the exhaust throttle solenoid valve
harness connector.
3. Connect the test lamp between the ignition
voltage feed circuit of the exhaust throttle
solenoid valve (pin 2 of J-59) and a known
good ground.
4. Turn ON the ignition, with the engine OFF.
Does the test lamp illuminate?
—
Go to Step 4 Go to Step 6
4
1. Connect a test lamp between the control
circuit (pin 1 of J-59) and battery voltage.
2. Perform the Exhaust Throttle Control with a
scan tool.
3. Command the solenoid valve ON and OFF.
Does the test lamp turn ON and OFF with
each command?
—
Go to Step 9 Go to Step 5
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