Isuzu N 2008 Series Workshop Manual page 192

Step
1. Test the vehicle speed signal circuit between
the ECM (pin 19 of J14) and the EHCU (pin 14
of J22) for a short to battery or ignition voltage.
4
2. Repair the circuit(s) as necessary.
Did you find and correct the condition?
Important: Replacement
programmed.
Replace the EHCU. Refer to EHCU in Section 4C1
5
ABS/ ASR.
Did you complete the replacement?
Important: Replacement
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. Start the engine.
7
5. Operate the vehicle within the Conditions for
Running the DTC. You may also operate the
vehicle within
observed from the Freeze Frame/ Failure
Records.
Did the DTC fail this ignition?
Observe the DTC Information with a scan tool.
8
Are there any DTCs that you have not diagnosed?
Action
EHCU must
ECM must
all previously disconnected
the conditions that
Engine Control System (4JJ1)
Value(s)
—
be
—
be
—
—
you
—
Yes
Go to Step 7 Go to Step 6
Go to Step 7
Go to Step 7
Go to Step 3 Go to Step 8
Go to DTC List
1A-189
No
—
—
System OK