Isuzu 4HL1 Workshop Manual page 116

1A-114 Engine Control System
Step
Check the AP sensor signal circuit for +B
short.
1. Starter switch "OFF".
2. Disconnect the ECM.
6
3. At the ECM connector pins, measure the
resistance.
Was the resistance within range?
Repair or replace the faulty harness.
7
Is the action complete?
Check the harness between ECM and AP
sensor for open wiring or short.
1. Starter switch "OFF".
2. Disconnect the ECM.
3. Disconnect the AP sensor connector.
4. Jumper the AP sensor connector pins
and measure the resistance at the ECM
connector.
8
Was the resistance within range?
Repair or replace the faulty harness.
9
Is the action complete?
Check the AP sensor.
1. At the AP sensor connector
10
measure the resistance.
Was the resistance within range?
Replace the AP sensor.
11
Is the action complete?
Review the DTC.
1. Certainly connect the AP sensor and
ECM connectors.
12
2. Using Tech 2, clear the DTC.
3. Perform test run and review the DTC.
Is DTC24 detected?
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
13
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Action
pins,
Value(s)
Pins 84-109/
114/115/116:
∞ Ω
Go to Step 10
Verify repair and
—
go to Step 12
Pins 94-84
(jumpered:
pins 1-2): 0 Ω
Pins 84-91
(jumpered:
pins 2-3): 0 Ω
Pins 94-90
(jumpered:
pins 1-3): 0 Ω
(not jumpered):
∞ Ω
Pins 94/84/
90-108
(not jumpered):
∞ Ω
Pins 94/84/
90/108-
ground
(not jumpered):
∞ Ω
Go to Step 10
Verify repair and
—
go to Step 14
Pins 1/2/3-
ground: ∞ Ω
Go to Step 12
Verify repair and
—
go to Step 14
—
Go to Step 13
—
Verify repair and
go to Step 14
Yes No
Go to Step 8
—
Go to Step 9
—
Go to Step 11
—
Refer to
Diagnostic Aids
—