Isuzu 4HL1 Workshop Manual page 207

Step
Check the idle position switch circuit (switch to
switch connector) for open wiring.
1. Disconnect
connector.
7
2. Measure the resistance between the idle
position switch connector pins while
operating the switch with a finger.
Was the resistance within range?
Check the idle position switch circuit (ground
circuit) for open wiring.
1. Measure the resistance between idle
8
position switch connector (ECM side) pin
2 and ground (e.g., frame or body).
Was the resistance within range?
Check the idle position switch circuit (ECM to
switch connector) for open wiring.
1. Disconnect the ECM.
2. Jumper the idle position switch connector
9
pin and measure the resistance at the
ECM connector.
Was the resistance within range?
Repair or replace the faulty harness.
10
Is the action complete?
Review the DTC.
1. Certainly connect the idle position switch
and ECM connectors.
11
2. Using Tech 2, clear the DTC.
3. Perform test run and review the DTC.
Is DTC241 detected?
1. Replace the ECM.
IMPORTANT:
If necessary (for the vehicle equipped with
12
idle stop function), input the number of
startups to the replacing ECM.
Is the action complete?
Check DTC241 will not be set again.
1. Using Tech 2, clear the DTC.
13
2. Perform test run and review the DTC.
Is DTC241 detected?
Action
the idle position switch
Engine Control System 1A-205
Value(s)
Switch-on
(switch is
released):
50 Ω, max.
Switch-off
(switch is
pressed): ∞ Ω
Go to Step 8
0 Ω
Go to Step 9
Pins 110-87:
0 Ω
Go to Step 11
—
Go to Step 13
—
Go to Step 12
—
Verify repair and
go to Step 13
—
Diagnostic Aids
and go to Step 2
Yes
Go to Step 10
Go to Step 10
Go to Step 10
Refer to
Diagnostic Aids
Refer to
Repair is
complete
No
—
—