Computers and Control Systems: Service Precautions

PRECAUTIONS

WARNING: Approximately 110 V is generated for the injector drive actuation system. For this reason, electrical shock may result if the injector circuit is touched directly by hand. Turn the starter switch "LOCK" position if it is necessary to check or repair the computer, harnesses, or connectors.

1. BE CAREFUL NOT TO LET DIRT OR DUST GET INSIDE THE ACTUATOR OR MAGNETIC VALVES.
2. HARNESS WIRE CONNECTOR.
1. Multi-contact connectors suitable for the small electrical signals of electronic circuitry are used for wiring connections to the sensors, actuator and control unit. Be very careful when handling them.
- Before disconnecting any connectors, make sure that the starter switch is in the "LOCK" position.
- When disconnecting connectors, try to pull them out in a straight line, disengaging the lock and holding onto the housing.
- Do not try to disconnect connectors by gripping the wires or twisting them, as this could bend the contacts.
- Do not disconnect connectors unnecessarily.
- When using a circuit tester, apply the tester probe to the harness wire side only. Never stick the tester probe into the holes on the connector terminal side, as this could cause poor contacts when the connector is reconnected.







- Do not let water, oil or dust get on the connector when it is disconnected, as this could cause poor contacts when the connector is reconnected.
- Do not open the control unit cover. It could malfunction if dust or water gets inside.
- Take care to ensure that water, oil or dust do not get on or inside parts.
- When connecting in connectors, push them in all the way and make sure that the lock engages.

3. ERASING THE MALFUNCTION MEMORY STORED IN THE PAST, CHECK THE CURRENT MALFUNCTION BY PERFORMING A DIAGNOSIS OF THE PRESENT MALFUNCTION AGAIN.
4. AFTER COMPLETING THE MALFUNCTION ANALYSIS, ERASE THE MALFUNCTION MEMORY STORED IN THE PAST. OTHERWISE, THE MALFUNCTION LAMP IN THE DISPLAY WILL REMAIN LIT.
5. CONNECTOR DRAWING, ALL OF WHICH HAS A VIEW TO BE SEEN FROM THE CONNECTION SIDE, INSERT THE TESTING LEAD FROM THE BACKSIDE.
6. USING A CIRCUIT TESTER
- Use a circuit tester with an internal resistance of 100 kohms or greater in the voltage measuring range.

7. USING A SIGNAL CHECK HARNESS
- To prevent breakage of the ECU connector, connect the signal check harness and perform measuring by bringing the test lead into contact with the signal check harness side (contact box).

NOTICE: The terminal numbers in the text and in the illustrations correspond to the table as shown below.












8. CONNECT THE SIGNAL CHECK HARNESS.
1. Disconnect the connectors from the ECU.
2. Connect a signal check harness to the vehicle harness and the ECU.
SST: Signal check harness [99731-Z5003 (J-47233)]
3. COMPUTER (ECU) PIN ASSIGNMENT








9. RADIO INSTALLATION
- There is a danger that the control unit might malfunction if a high output radio transmitter (over 50 W) is installed in the vehicle.

10. USING A QUICK CHARGER
- Disconnect both battery terminals before using a quick charger.

11. AIR CONDITIONER INSTALLATION
- Be careful not to scratch or damage the engine, chassis or the harness inside the cab when installing an air conditioner. Also, make sure to reattach afterward any connectors that were disconnected during the installation process.

12. PERFORMING ELECTRIC WELDING
- Disconnect connector to the control unit before performing any electric welding.

13. OTHER
- Make sure to check the other connectors before connecting them in to prevent incorrect connections.
- Be careful not to allow the connectors to become soiled with dust, water, fuel or oil when performing inspections or removing and replacing parts.