Isuzu 4ja1, Workshop Manual

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Engine Control System (4JH1) 6E-57
DTC P0100 (Symptom Code B) (Flash Code 65)
Circuit Description
The mass air flow (MAF) sensor is an air flow meter that
measures the amount of air that enters the engine. It is
fitted between the air cleaner and turbocharger. A small
quantity of air that enters the engine indicates
deceleration or idle speed. A large quantity of air that
enters the engine indicates acceleration or a high load
condition. The MAF sensor has the following circuits.
•
Ignition voltage circuit
•
5 volts reference circuit
•
Low reference circuit
•
MAF sensor signal circuit
The engine control module (ECM) monitors the MAF
sensor signal for voltage outside the normal range of
the MAF sensor. If the ECM detects an excessively low
MAF sensor signal voltage, this DTC will set.
Condition for Running the DTC
•
The ignition switch is ON.
•
The engine is running.
Condition for Setting the DTC
•
The ECM calculated MAF is lower than -18.6 kg/h
for 5 seconds. This indicates the ECM detects that
the MAF sensor signal voltage is smaller than a
predetermined range during engine run.
Action Taken When the DTC Sets
•
The ECM illuminates the malfunction indicator
lamp (MIL) when the diagnostic runs and fails.
•
The ECM uses a MAF substitution of 1600 mg/strk
for engine control.
•
The ECM uses an EGR solenoid valve control
substitution of 10%.
Condition for Clearing the MIL/DTC
•
The ECM turns OFF the MIL that 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.
Notice:
•
Wrong direction of MAF sensor installation will
cause this DTC to set.
•
Contaminated or restricted MAF sensor will cause
this DTC to set.
•
The MAF Sensor parameter on the scan tool will
only update with engine running.
Test Description
The number below refers to the step number on the
diagnostic table.
7. If the MAF sensor signal circuit between the ECM
and the sensor is short to ground or any low reference
circuits, the sensor 5 volts reference voltage low DTC
P0100 (Symptom Code 9) will set.
8. If the MAF sensor signal circuit between the ECM
and the sensor is normal, the sensor signal voltage high
DTC P0100 (Symptom Code C) will set.
DTC P0100 (Symptom Code B) (Flash Code 65)
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.
Does the DTC fail this ignition?

Go to Step 3
Go to Diagnostic
Aids
3 1. Turn OFF the ignition.
2. Inspect the ECM (10A) fuse (EB-4) in the engine
room fuse block.
Is the ECM (10A) fuse (EB-4) open?

Go to Step 4 Go to Step 5
4 Replace the ECM (10A) fuse (EB-4). If the fuse
continues to open, repair the short to ground on one
of the circuits that is fed by the ECM (10A) fuse (EB-
4) or replace the shorted attached component fed by
the ECM (10A) fuse (EB-4).
Did you complete the repair?

Go to Step 17
