Isuzu 4HL1 Workshop Manual page 138

1A-136 Engine Control System
Step
Check the circuit ground common or common
power circuit to ITP, EGR position and
common rail pressure sensors for open wiring
or short.
1. Starter switch "OFF".
2. Disconnect the ECM.
3. Disconnect the ITP sensor connector.
7 4. Jumper the ITP sensor connector 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 ITP sensor and
ECM connectors.
9
2. Using Tech 2, clear the DTC.
3. Perform test run and review the DTC.
Is DTC43 detected?
Check the ITP sensor output voltage.
1. Install Tech 2.
2. Starter switch "ON", and display the
engine data.
10
3. Observe the "Intake Throttle Valve"
display for output voltage.
Was the voltage within range?
Check the ITP sensor output voltage.
11
Is the voltage 5 V or more?
Check the ITP sensor SIG circuit for +B short.
1. Starter switch "OFF".
2. Disconnect the ECM.
12
3. At the ECM connector pins, measure the
resistance.
Was the resistance within range?
Repair or replace the faulty harness.
13
Is the action complete?
Action Value(s)
Pins 64-63
(not jumpered):
∞ Ω
Pins 64-
ground
(jumpered):
Pins 1-
ground: 0 Ω
(not jumpered):
∞ Ω
Pins 63-
ground
(jumpered):
Pins 4-
ground: 0 Ω
(not jumpered):
∞ Ω
Go to Step 9
Verify repair and
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go to Step 9
—
Go to Step 10
Approx. 4 V
Go to Step 18
—
Go to Step 12
Pins 69-109/
114/115/116:
∞ Ω
Go to Step 14
Verify repair and
—
go to Step 18
Yes No
Go to Step 8
Refer to
Diagnostic Aids
Go to Step 11
Go to Step 14
Go to Step 13
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