Diagnostic block
A - contact connected to ground;
B - diagnostic contact for signaling the ECU;
G - contact for controlling the electric fuel pump;
M - contact for issuing information (serial data channel)
Issuance of code 12 by a control lamp "CHECK ENGINE"
The diagnostic block is used to communicate with the computer. It is located under the glove box on the right side next to the computer.
Fault codes stored in the ECU memory can be read either with a special diagnostic tool or by counting the number of lamp flashes "CHECK ENGINE". To read the codes with a lamp, you must connect the contact "IN" (see fig. Diagnostic block) diagnostic pads with ground. The easiest way to close it to ground is by connecting it to a contact "A", which is connected to the engine ground.
When contacts "A" And "IN" are interconnected, the key in the ignition switch must be turned to position III (Ignition), but the engine should not run. Under these conditions, the lamp "CHECK ENGINE" should flash code 12 three times in a row. This should happen in this order: flash, pause (1–2 s), flash, flash - long pause (2–3 s), and twice more (see fig. Issuance of code 12 by a control lamp "CHECK ENGINE").
Code 12 indicates that the ECU diagnostic system is working. If code 12 is not displayed, then there are problems in the diagnostic system itself.
After displaying code 12, the lamp "CHECK ENGINE" Displays fault codes three times if they exist, or simply continues to display code 12 if there are no fault codes.
If more than one fault code is stored in the ECU memory, then they are displayed 3 times each.
Attention! At the end of the diagnostics, open the contacts "A" And "IN" diagnostic pads is allowed 10 seconds after the ignition is turned off.
Erasing codes
The codes are erased from the computer memory either after the repair is completed or in order to see if the malfunction occurs again. To erase, it is necessary to turn off the power to the computer for at least 10 s.
The power can be turned off either by disconnecting the wire from the terminal "minus" battery, or by removing the ECU protection fuse from the fuse box.
Attention! In order not to damage the computer, it is necessary to turn off and turn on its power only when the ignition is off.