Isuzu N 2008 Series Workshop Manual page 255

1A-252 Engine Control System (4JJ1)
Step
Connect a test lamp between the charge voltage
circuit (pin 2 of E5 or E8) and a known good
4
ground.
Does the test lamp illuminate?
Connect a test lamp between the charge voltage
circuit (pin 2 of E5 or E8) and battery voltage.
5
Does the test lamp illuminate?
1. Test the control circuits between the ECM and
the fuel injector for the short to ground.
• Cylinder #1: Between pin 119 of E12 and
1 of E5
6
• Cylinder #4: Between pin 117 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 121 of E12) and the fuel injector (pin
2 of E5 or E8) 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 121 of E12) and the fuel injector (pin
2 of E5 or E8) 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 #1
and #4 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 121 of E12).
4. Inspect for an open circuit or high resistance
on the charge voltage circuit between the
10
ECM (pin 121 of E12) and the cylinder #1 fuel
injector (pin 2 of E5) or cylinder #4 fuel injector
(pin 2 of E8).
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?
Action
injector must
Value(s)
—
—
—
—
—
1 MΩ
—
be
—
Yes
Go to Step 7 Go to Step 5
Go to Step 8 Go to Step 9
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
No
—