Isuzu 4JA1 Workshop Manual page 300

6E-46 Engine Control System (4JH1)
Step Action Value(s) Yes No
17 1. Turn OFF the ignition.
2. Reconnect all disconnected connectors.
3. Turn the ignition ON with the engine OFF.

4. Attempt to establish scan tool communications
with the ECM.
Does the scan tool communicate with the ECM? System OK Go to Step 3