Removal and installation of engine control unit "J623" (without protective housing)
Switch on the ignition and select Tester. Press the following buttons on the display one after the other: 01 - Engine electronics, 01 - Guided functions, 01 - Basic setting, 01 - Engine control unit replacement. Switch off the ignition and remove the ignition key from the lock.
Note: During production, several versions of the J623 engine control unit brackets were installed. The order of operations for removal and installation remains unchanged.
Move the lock in the direction of arrow A and remove the control unit "arrow B". Unlock and disconnect the connectors of the engine control unit "J623".
Installation
Install the engine control unit with the lower edge forward "arrow A". The jumpers of the engine control unit "J623" must fall into the upper and lower recesses "arrow B".
After installing the engine control unit, the following work must be performed. Operate the engine control unit "J623" as follows: switch on the ignition and select Tester. Press the following buttons on the display one after the other: 01 - Engine electronics, 01 - Guided functions, 01 - Basic setting, 01 - Replacing the engine control unit.
Removal and installation of engine control unit "J623" (with protective housing)
Switch on the ignition and select Tester. Press the following buttons on the display one after the other: 01 - Engine electronics, 01 - Guided functions, 01 - Basic setting, 01 - Engine control unit replacement. Switch off the ignition and remove the ignition key from the lock. Unscrew the shear bolts "arrows" to remove the protective housing "1" as follows.
Cut a slot for a screwdriver in the head of the shear bolt "1" using a mini drill "2".
Note: The threads of the shear bolts are coated with thread locking compound. Heating the shear bolt while grinding the slot for the screwdriver makes it easier to unscrew. If the shear bolts do not unscrew, heat them with an industrial hair dryer.
Heating shear bolts with an industrial hair dryer
Set the temperature setting potentiometer "2" to maximum heat output and the two-position air quantity switch "3" to position 3.
Heat the head of shear bolt "1" for approximately 20-30 seconds.
Next, with the bolts loosened
Unscrew the shear bolt "1" with screwdriver "2".
Caution! Do not allow the engine control unit to come into contact with the positive terminal of the battery - risk of damage. During production, several versions of the "J623" engine control unit brackets were installed. The order of operations during removal and installation remains unchanged.
Move the lock in the direction of arrow A and remove the control unit "arrow B". Unlock and disconnect the connectors of the engine control unit "J623".
Installation
Installation is carried out in the reverse order. Install the engine control unit with the lower edge first "arrow A". The jumpers of the engine control unit "J623" must fall into the upper and lower recesses "arrow B". Be sure to close the engine control unit "J623" again with the protective cover. Clean the threaded holes for the new shear bolts from the remains of the thread locking agent. You can clean the threads with a tap. Use new shear bolts during installation. After installing the engine control unit, the following work must be carried out. Operate the engine control unit "J623" as follows: switch on the ignition and select Tester. Press the following buttons on the display one after the other: 01 - Engine electronics, 01 - Guided functions, 01 - Basic setting, 01 - Replacing the engine control unit.