Isuzu 4ja1, Workshop Manual

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6E-68 Engine Control System (4JH1)
DTC P0105 (Symptom Code 7) (Flash Code 34)
Circuit Description
The vacuum pressure sensor is installed to the
turbocharger wastegate control hose and it detects the
regulated vacuum pressure to the turbocharger
wastegate valve. The vacuum pressure sensor is a
transducer that varies voltage according to changes in
the vacuum pressure inside the vacuum hose. The
vacuum pressure sensor has the following circuits.
•
5 volts reference circuit
•
Low reference circuit
•
Vacuum pressure sensor signal circuit
The engine control module (ECM) supplies 5 volts to
the vacuum pressure sensor on the 5 volts reference
circuit. The ECM also provides a ground on the low
reference circuit. If the ECM detects an excessively high
vacuum pressure sensor 5 volts reference voltage, this
DTC will set.
Condition for Running the DTC
•
The ignition switch is ON.
Condition for Setting the DTC
•
The ECM detects that the vacuum pressure
sensor 5 volts reference circuit voltage is more
than 5.2 volts for 2.5 seconds.
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.
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.
DTC P0105 (Symptom Code 7) (Flash Code 34)
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.
4. Monitor the Diagnostic Trouble Code (DTC)
Information with the scan tool.
Does the DTC fail this ignition?

Go to Step 3
Go to Diagnostic
Aids
3 1. Test the 5 volts reference circuit between the
engine control module (ECM) (pin 1 of C-57
connector) and the vacuum pressure sensor (pin
3 of C-124 connector) for a short to battery or
ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?

Go to Step 5 Go to Step 4
4 Important: Replacement ECM must be
programmed.
Replace the ECM. Refer to Engine Control Module
(ECM) Replacement in this section.
Did you complete the replacement?

Go to Step 5

5 1. Reconnect all previously disconnected harness
connector(s).
2. Clear the DTCs with the scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Monitor the DTC Information with the scan tool.
Did the DTC fail this ignition?

Go to Step 3 Go to Step 6