Isuzu 2008MY N Series, Руководство по ремонту

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Engine Control System (4HK1) 1A-189
DTC P042C or P042D (Flash Code 49)
Circuit Description
The exhaust temperature sensor 2 is installed to the
diesel particulate defuser (DPD) housing. The exhaust
temperature sensor 2 is a variable resistor and it
measures the temperature of the exhaust gas in front of
oxygen catalyst. The sensor has a signal circuit and a
low reference circuit. The ECM supplies 5 volts to the
signal circuit and a ground for the low reference circuit.
When the exhaust temperature sensor 2 is cold, the
sensor resistance is high. When the exhaust
temperature increases, the sensor resistance
decreases. With high sensor resistance, the ECM
detects a high voltage on the signal circuit. With lower
sensor resistance, the ECM detects a lower voltage on
the signal circuit. If the ECM detects an excessively low
or high signal voltage, DTC P042C or P042D will set.
Condition for Running the DTC
• DTCs P060B and P0697 are not set. (DTC P042C)
• DTCs P0112, P0113, P0116, P0117, P0118,
P060B, P0651, P0697, P2227, P2228 and P2229
are not set. (DTC P042D)
• The battery voltage is between 18 to 32 volts.
• The ignition switch is ON.
• The engine speed is more than 1400RPM. (DTC
P042D)
• The engine coolant temperature is more than 80
°
C
(176
°
F). (DTC P042D)
• The fuel injection quantity is more than a
predetermined value. (DTC P042D)
• The vehicle is running or the PTO control is
inactive.
• The engine run time is longer than 5 to 10 minutes.
(DTC P042D)
Condition for Setting the DTC
• The ECM detects that the exhaust temperature
sensor 2 signal voltage is less than 0.2 volts for 3
seconds. (DTC P042C)
• The ECM detects that the exhaust temperature
sensor 2 signal voltage is more than 4.85 volts for
5 seconds. (DTC P042D)
Action Taken When the DTC Sets
• The ECM illuminates the SVS lamp when the
diagnostic runs and fails. Refer to DTC Type
Definitions for Action Taken When the DTC Sets -
Type C.
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the SVS Lamp/ DTC - Type C.
Diagnostic Aids
• If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
• Use the Temperature vs. Resistance table to test
the exhaust temperature sensor 2 at various
temperature levels to evaluate the possibility of a
skewed sensor.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Circuit/ System Testing DTC P042C
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 Temperature Sensor 2
parameter with a scan tool.
Is the Exhaust Temperature Sensor 2
parameter less than the specified value?
0.2 volts
Go to Step 4
Go to Diagnostic
Aids
LG4HKED-WE-0871.book 189 ページ ２００７年１１月２９日 木曜日 午後６時２９分