Isuzu N 2008 Series Workshop Manual page 257

1A-254 Engine Control System (4JJ1)
Step
1. Test the control circuits between the ECM and
the fuel injector for the short to ground.
• Cylinder #2: Between pin 118 of E12 and
1 of E7
6
• Cylinder #3: Between pin 120 of E12 and
1 of E8
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the charge voltage circuit between the
ECM (pin 116 of E12) and the fuel injector (pin
2 of E6 or E7) for the short to battery or
7 ignition voltage.
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
1. Test the charge voltage circuit between the
ECM (pin 116 of E12) and the fuel injector (pin
2 of E6 or E7) for the short to ground.
8
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Measure insulation resistance of the cylinder #2
and #3 fuel injector between each fuel injector
9
terminal and a known good ground.
Is the resistance more than the specified value?
1. Turn OFF the ignition.
2. Disconnect the ECM harness connector.
3. Inspect for an intermittent and for a poor
connection at the harness connector of the
ECM (pin 116 of E12).
4. Inspect for an open circuit or high resistance
on the charge voltage circuit between the
10
ECM (pin 116 of E12) and the cylinder #2 fuel
injector (pin 2 of E6) or cylinder #3 fuel injector
(pin 2 of E7).
5. Repair the connection(s) or circuit(s) as
necessary.
Did you find and correct the condition?
Important: Replacement
programmed.
Replace the appropriate fuel injector that was less
11
insulation resistance found at Step 9. Refer to
Injector in Section 1D Engine Fuel.
Did you complete the replacement?
Important:
programmed and learned.
12
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
Action
injector
Replacement ECM
Value(s)
—
—
—
1 MΩ
—
must be
—
must be
—
Yes
Go to Step 13 Go to Step 12
Go to Step 13 Go to Step 12
Go to Step 13 Go to Step 12
Go to Step 10 Go to Step 11
Go to Step 13 Go to Step 12
Go to Step 13
Go to Step 13
No
—
—