Isuzu 4HL1, Workshop Manual

Page: 127 / 267

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