Isuzu 4HL1 Workshop Manual page 127

Step
Check the idle up volume switch circuit
harness for open wiring or short.
1. Starter switch "OFF".
2. Disconnect the VIM.
3. Disconnect the idle up volume switch
connector.
4. Jumper the idle up volume switch
connector and measure the resistance at
8 the VIM connector.
Was the resistance within range?
Repair or replace the faulty harness.
9
Is the action complete?
Check the idle up volume switch.
1. Remove the idle up volume switch.
2. Test the continuity between idle up
10
volume switch connector pins,
Was the resistance within range?
Replace the idle up volume switch.
11
Is the action complete?
Review the DTC.
1. Certainly connect the idle up volume
switch and VIM connectors.
12
2. Using Tech 2, clear the DTC.
3. Perform test run and review the DTC.
Is DTC31 detected?
1. Replace the VIM.
IMPORTANT:
If necessary (for the vehicle equipped with
13
idle stop function), input the number of
startups to the replacing VIM.
Is the action complete?
Check DTC31 will not be set again.
1. Using Tech 2, clear the DTC.
14
2. Perform test run and review the DTC.
Is DTC31 detected?
Action
Engine Control System 1A-125
Value(s)
Pins 71-34
(jumpered:
pins 1-2): 0 Ω
(not jumpered):
∞ Ω
Pins 31-34
(jumpered:
pins 2-3): 0 Ω
(not jumpered):
∞ Ω
Pins 71-31
(jumpered:
pins 1-3): 0 Ω
(not jumpered):
∞ Ω
Pins 71/34/
31-ground
(not jumpered):
∞ Ω
Go to Step 12
Verify repair and
—
go to Step 14
Pins 1-2:
Discontinued
Pins 2-3:
Discontinued
Pins 1-3:
Continued
Go to Step 12
Verify repair and
—
go to Step 14
—
Go to Step 13
—
Verify repair and
go to Step 14
—
Refer to
Diagnostic Aids
and go to Step 2
Yes No
Go to Step 9
Go to Step 11
Refer to
Diagnostic Aids
Repair is
complete
—
—
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