Isuzu 2008MY N Series Workshop Manual page 76

Circuit/ System Testing DTC P0080
Step
Did you perform the Diagnostic System Check
1
- Engine Controls?
1. Install a scan tool.
2. Perform the Exhaust Throttle Control with a
scan tool.
2
3. Command the solenoid valve ON and OFF.
Does the solenoid valve click with each
command?
1. Turn OFF the ignition.
2. Remove the exhaust throttle solenoid valve.
3. Turn ON the ignition, with the engine OFF.
3
4. Monitor the DTC Information with a scan tool.
Is DTC P0079 set, but not DTC P0080?
1. Test the control circuit between the ECM (pin
102 of E-12) and the solenoid valve (pin 1 of
J-59) for a short to battery or ignition voltage.
4
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Replace the exhaust throttle solenoid valve.
5
Did you complete the replacement?
Important:
programmed and learned.
6
Replace the ECM. Refer to ECM Replacement.
Did you complete the replacement?
1. Reconnect
harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Perform the Exhaust Throttle Control with a
7
scan tool.
5. Command the solenoid valve ON and OFF.
Does the exhaust throttle solenoid valve click
with each command?
Observe the DTC Information with a scan tool.
8
Are there any DTCs that you have not
diagnosed?
Action
Replacement ECM
all previously disconnected
Engine Control System (4HK1)
Value(s)
—
—
—
—
—
must be
—
—
—
Yes
Go to Diagnostic
System Check -
Go to Step 2 Engine Controls
Go to Diagnostic
Aids
Go to Step 5
Go to Step 7
Go to Step 7
Go to Step 7
Go to Step 8
Go to DTC List
1A-73
No
Go to Step 3
Go to Step 4
Go to Step 6
—
—
Go to Step 3
System OK