Isuzu 4HL1 Workshop Manual page 143

Step
Check the circuit ground common or common
power circuit to ITP sensor, EGR position
sensor and common rail pressure sensors for
open wiring or short.
1. Starter switch "OFF".
2. Disconnect the ECM.
3. Disconnect the EGR position sensor.
7 4. Jumper the EGR sensor connector pin
and measure the resistance at the ECM
connector.
Was the resistance within range?
Repair or replace the faulty harness.
8
Is the action complete?
Review the DTC.
1. Certainly connect the EGR position
sensor and ECM connectors.
9
2. Using Tech 2, clear the DTC.
3. Perform test run and review the DTC.
Is DTC44 detected?
Check the EGR valve position sensor output
voltage.
10
Is the voltage 5 V or more?
Check the EGR valve position sensor circuit
for +B short.
1. Starter switch "OFF".
2. Disconnect the ECM.
11
3. At the ECM connector pins, measure the
resistance.
Was the resistance within range?
Repair or replace the faulty harness.
12
Is the action complete?
Action
Engine Control System 1A-141
Value(s)
Pins 64-63
(not jumpered):
∞ Ω
Pin 64-
ground
(jumpered:
2-ground):
0 Ω
(not jumpered):
∞ Ω
Pins 63-
ground
(jumpered:
1-ground):
0 Ω
(not jumpered):
∞ Ω
Go to Step 9
Verify repair and
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go to Step 9
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Go to Step 10
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Go to Step 11
Pins 63/68/
64-109/114/
115/116:
∞ Ω
Go to Step 16
Verify repair and
—
go to Step 17
Yes No
Go to Step 8
Refer to
Diagnostic Aids
Go to Step 13
Go to Step 13
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