Repair instructions Calibration of accelerator linkage General advice on working with EDC Changing the control unit Calibration of EDC unit NOTE! The figures in the repair instructions below ap- ply to the TWD1231VE, but the principles are the same for the TWD740VE. The engine must be calibrated when controlled by the accelerator potentiometer. Follow the instructions below, to avoid damage to the EDC system control unit. When calibrating, it is a good idea to install a switch (1) between pin 2 in the “Female Connector“ in the junction box, and the positive battery terminal, as in the adjacent sketch.
The voltage can also be taken from the positive (+) terminal in the junction box, or from the battery. The switch should be spring biased and “normally open“. Never turn off the main switch when the en- gine is running. Never undo the battery cables when the en- gine is running. When the batteries are quick charged, turn the main switch off or undo the battery ca- bles. During normal maintenance charging, the main switch does not need to be turned off. Only batteries may be used for start help. Quick starting units can give excess voltag- es and damage the control unit. Disconnect the main switch before undoing the 42 pin connector on the control unit.
If you discover any damage on the cable har- nesses, undo the connector on the control unit. Calibration 1. Set the accelerator to idling. 2. Erase any fault codes (please refer to the “Function checking with diagnosis button“ chapter). 1. Control unit 2. Fuel fine filter 3. Connector 4. Hose connector, charge pressure Control unit with connectors 3. Switch off system voltage. 4. Press switch (1). Keep the switch depressed and switch the current on. Then keep the switch de- pressed for a further 3 seconds. IMPORTANT! Always undo the connector on the control unit before doing any welding. 1. Clean the filter bracket carefully. 5. Release the switch.
The diagnosis lamp should now flash, as a confirmation that the EDC sys- tem is in calibration mode. When a connector is undone from a sensor, be careful to ensure that the connector pins are not exposed to oil or other fluids. This can cause contact problems. 6. Move the accelerator to full throttle position. Keep the control in this position. Acknowledge by pressing the switch for at least 3 seconds. DIAGNOSTIC BUTTON 7. Move the accelerator to idling position. Keep the control in this position. Acknowledge by pressing switch (1) for at least three seconds. 8. Finish calibrating by pressing the switch again. The diagnosis lamp will stop flashing and calibra- tion is completed. 2.
Remove the control unit connector, by insert- ing a screwdriver between the red catch arm and the connector. Turn the screwdriver to partly pull the catch arm out of the connector. 28 25