Go To Step - Isuzu 4HL1 Workshop Manual

Diagnostic Aids
Poor connection or damaged harness may cause
intermittents. Check for the following conditions and, if
the fault is detected, repair or replace the faulty portion.
• Poor connection
connectors for backed-out pins, improper mating,
broken locks, improperly formed or damaged pins,
and poor pin-to-wire connection.
• Damaged harness: Inspect the wiring harness for
rubbed-through wire insulation or wire broken
inside the insulator. If the harness appears to be
OK, observe the display on Tech 2 while moving
Step
Perform the "On-Board Diagnostic (OBD)
System Check".
1
Was the OBD System Check performed?
Check the ECM connector for installation and,
if mounted improperly, install the device
2
certainly.
Is the action complete?
Review the DTC.
1. Using Tech 2, check and store the DTC.
2. Clear the DTC.
3
3. Perform test run and review the DTC.
Is DTC84 detected?
Check the CAN communication circuit.
1. Starter switch "OFF".
2. Disconnect ECM and VIM connectors.
3. Jumper the VIM connector and measure
the resistance at the ECM connector.
Was the resistance within range?
4
Repair or replace the faulty harness.
5
Is the action complete?
at ECM: Inspect
Action
connectors and wiring harnesses related to the
sensor. A change in the display will indicate the
location of the fault.
Test Description
harness
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. If the DTC is not detected, the possible cause is
intermittent (intermittent fault).
4. If pins are jumpered and the resistance reads ∞ Ω,
the cause is open wiring. If pins are not jumpered and
the resistance reads 0 Ω, the cause is short.
Value(s)
—
—
—
ECM pins 89-
97 (jumpered:
VIM pins 26-
27): 0 Ω
(not jumpered):
∞ Ω
ECM pins 89-
ground
(jumpered:
VIM pins 27-
ground): 0 Ω
(not jumpered):
∞ Ω
ECM pins 97-
ground
(jumpered:
VIM pins 26-
ground): 0 Ω
(not jumpered):
∞ Ω
—
Engine Control System 1A-167
Yes

Go to Step 2

and go to Step 2
Go to Step 3
Go to Step 4 Diagnostic Aids
Go to Step 6
Verify repair and
go to Step 10
No
Refer to OBD
System Check
—
Refer to
Go to Step 5
—