Isuzu 4ja1, Workshop Manual

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6E-94 Engine Control System (4JH1)
DTC P0243 (Symptom Code 3) (Flash Code 64)
Circuit Description
The engine control module (ECM) controls the
turbocharger wastegate valve based on the barometric
pressure in order to reduce turbocharger spinning
speeds at high altitude area. The ECM controls the
turbocharger wastegate valve diaphragm by acting the
regulated vacuum pressure via controlling the solenoid
valve. The vacuum pressure sensor monitors the
regulated vacuum pressure to the turbocharger
wastegate valve. The ECM calculates desired vacuum
pressure and it compares the calculated desired
vacuum pressure to the actual value to determine the
solenoid valve position. When the actual vacuum
pressure is higher than the desired value, the solenoid
valve is closed to decrease the vacuum pressure. An
expected vacuum pressure amount should be detected
while the engine running. If the ECM detects the actual
vacuum pressure amount is higher than desired
vacuum pressure amount, this DTC will set.
Condition for Running the DTC
•
The ignition switch is ON.
•
The barometric pressure (BARO) is between 0
hPa and 3500 hPa.
•
The intake air temperature (IAT) is between -50°C
(-58 °F) and 200°C (392°F).
•
The engine coolant temperature (ECT) is between
-50°C (-58 °F) and 150°C (302°F).
Condition for Setting the DTC
•
The ECM detects that the vacuum pressure is 50
hPa higher than the desired vacuum pressure for
3 seconds. This indicates excessive high vacuum
pressure.
Action Taken When the DTC Sets
•
The ECM illuminates the malfunction indicator
lamp (MIL) when the diagnostic runs and fails.
•
The ECM limits fuel injection quantity.
•
The ECM uses an EGR solenoid valve control
substitution of 10%.
Condition for Clearing the MIL/DTC
•
The ECM turns OFF the MIL when the diagnostic
runs and does not fail.
•
A history DTC clears after 40 consecutive driving
cycles without a fault. Or clear with the scan tool.
Diagnostic Aids
•
If an intermittent condition is suspected, refer to
Intermittent Conditions in this section.
•
Misrouted vacuum hoses will cause this DTC to
set.
Test Description
The numbers below refer to the step number on the
diagnostic table.
4. A skewed vacuum pressure sensor value (shifted to
a high pressure) can set this DTC. The Vacuum
Pressure on the scan tool should read near doubled
barometric pressure (BARO) with the key ON and
engine OFF.
5. A skewed BARO sensor value (shifted to a lower
pressure) may set this DTC. The BARO on the scan
tool should read near surrounding barometric pressure.
DTC P0243 (Symptom Code 3) (Flash Code 64)
Schematic Reference:
Engine Controls Schematics
Connector End View Reference: Engine Controls
Connector End Views or Engine Control Module (ECM)
Connector End Views
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 the scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine and let idle for 30 seconds.
4. Monitor the Diagnostic Trouble Code (DTC)
Information with the scan tool.
Is DTC P0105 (Symptom Code 1, 2, 7 or 9) or
P0243 (Symptom Code 4 or 8) set?

Go to Applicable
DTC Go to Step 3