Dtc P042B (Flash Code 145) - Isuzu 2008MY N Series Workshop Manual

DTC P042B (Flash Code 145)

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. If the ECM detects an excessively high
exhaust temperature, this DTC will set.
Condition for Running the DTC
• DTCs P042C, P042D, P060B and P0697 are not
set.
• The ignition switch is ON.
Condition for Setting the DTC
• The ECM detects that exhaust temperature 2 (in
front of oxygen catalyst) is higher than 870°C
(1600 °F) for 5 seconds.
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.
Circuit/ System Testing DTC P042B
Step
Did you perform the Diagnostic System Check
1
- Engine Controls?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
2
4. Monitor the DTC Information with a scan tool.
Is DTC P0093, P042C or P1093 also set?
1. Test the exhaust temperature sensor 2 at
various temperature levels to evaluate the
possibility of a skewed sensor.
2. Replace the exhaust temperature sensor as
3
necessary. Refer to Exhaust Temperature
Sensor in Section 1G Engine Exhaust.
Did you find and correct the condition?
1. Remove the diesel particulate defuser (DPD)
assembly. Refer to Exhaust Pipe in Section
1G Engine Exhaust.
2. Inspect the DPD filter and the oxygen catalyst
for damage, cracks or melt.
4
Important: DPD status in the ECM must be
reset when the DPD filter is replaced.
3. Replace the DPD filter or the oxygen catalyst
as necessary. Refer to Exhaust Pipe in
Section 1G Engine Exhaust.
Did you find and correct the condition?
Action
Engine Control System (4HK1)
• The ECM limits fuel injection quantity
Condition for Clearing the DTC
• Refer to DTC Type Definitions for Condition for
Clearing the SVS Lamp/ DTC - Type C.
Diagnostic Aids
• Use the Temperature vs. Resistance table to test
the exhaust temperature sensor at various
temperature levels to evaluate the possibility of a
skewed sensor.
• Fuel system problem (e.g. fuel injector damage)
may set this DTC.
Notice: This DTC is caused by an excessively high
exhaust temperature condition, which was most likely
caused by uncontrolled burning while regeneration
process of DPD filter. Excessive high exhaust gas
temperature may damage DPD filter.
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views
Value(s) Yes
—
Go to Step 2
—
Go to Applicable
DTC
—
Go to Step 5
—
Go to Step 5
1A-187
No
Go to Diagnostic
System Check -
Engine Controls
Go to Step 3
Go to Step 4
Go to Diagnostic
Aids