1A-240 Engine Control System
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 at ECM: Inspect harness
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
connectors and wiring harnesses related to the
sensor. A change in the display will indicate the
location of the fault.
Step
Action
Value(s)
Yes
No
1
Perform the "On-Board Diagnostic (OBD)
System Check".
Was the OBD System Check performed?
—
Go to Step 2
Refer to OBD
System Check
and go to Step 2
2
Check the injector connector for installation
and, if mounted improperly, connect it
certainly.
Is the action complete?
—
Go to Step 3
—
3
Review the DTC.
1.
Using Tech 2, check and store the DTC.
2.
Clear the DTC.
3.
Perform test run and review the DTC.
Is DTC278 detected?
—
Go to Step 4
Refer to
Diagnostic Aids
4
Check the common 2 injector drive circuit
(ECM to intermediate connector) for open
wiring.
1.
Disconnect the ECM.
2.
Disconnect the injector connector.
3.
Jumper the injector connector and
measure the resistance at the ECM
connector.
Was the resistance within range?
Pins 4-
ground
(jumpered:
2/3-ground):
0
Ω
(not jumpered):
∞
Ω
Pins 5-
ground
(jumpered:
2/3-ground):
0
Ω
(not jumpered):
∞
Ω
Pins 4-5
(not jumpered):
0
Ω
Go to Step 5
Go to Step 8
5
Check the intermediate connector for fault.
1.
Disconnect ECM side and injector side
connectors from the intermediate
connector.
2.
Remove the intermediate connector from
the engine block.
3.
Jumper the intermediate connector that
was connected to the injectors and
measure the resistance at the
intermediate connector that was
connected to the ECM pins.
Was the resistance within range?
Pins 1-2/3/4
(jumpered:
1-2/3/4): 0
Ω
(not jumpered):
∞
Ω
Pins 2-3/4
(jumpered:
2-3/4): 0
Ω
(not jumpered):
∞
Ω
Pins 3-4
(jumpered:
3-4): 0
Ω
(not jumpered):
∞
Ω
Go to Step 7
Go to Step 6
Summary of Contents for 4HL1
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