10.7.3. Controller (electronic control unit)

The controller (electronic control unit) represents the operating center of system of injection of fuel. It continuously processes information from various sensors and operates the systems influencing toxicity of the fulfilled gases and operational indicators of the car.
The following information comes to the controller:
– situation and frequency of rotation of a bent shaft;
– mass consumption of air engine;
– temperature of cooling liquid;
– provision of a butterfly valve;
– content of oxygen in the fulfilled gases;
– existence of a detonation in the engine;
– tension in onboard network of the car;
– car speed;
– position of the camshaft;
– request for turning on of the conditioner (on cars in alternative execution).
On the basis of the obtained information the controller operates the following systems and devices:
– fuel feeding (nozzles and electrogasoline pump);
– system of ignition;
– idling regulator;
– adsorber of system of catching of vapors of gasoline;
– engine cooling system fan;
– system of diagnostics.
The controller includes output chains (nozzles, various relays, etc.) by their short circuit on "weight" via output transistors of the controller. The only exception — a chain of the relay of the fuel pump, only on a winding of this relay the controller gives tension of +12 Century.
The controller is equipped with the built-in system of diagnostics. He can distinguish malfunctions in work of system, warning about them the driver through a control lamp of a control system of the engine. Besides, the controller stores the diagnostic codes specifying areas of malfunction to help experts with carrying out repair.
The controller has the following types of memory:
– programmable read-only memory (PROM);
– operational memory device (OMD);
– electrically reprogrammiruyemy read-only memory (ERROM).
Programmable Read-only Memory (PROM). In it there is the general program which contains the sequence of working teams (control algorithms) and various calibration information. This information represents data of management of injection, ignition, idling, etc. which depend on the mass of the car, type and engine capacity, the transfer relations of transmission and other factors. PPZU call still the memory device of calibrations. Contents of PPZU cannot be changed after programming. This memory does not need food for saving information which is written down in it which is not erased at power off, i.e. this memory non-volatile.
Operational Memory Device (OMD). It is controller "notebook". The microprocessor of the controller uses it for temporary storage of the measured parameters for calculations and the interim information. The microprocessor can enter as required data in it or read out them.
The chip of the RAM is mounted on the printed circuit board of the controller. This memory volatile, demands uninterrupted food for preservation. At interruption in supply of food the diagnostic codes of malfunctions and settlement data which are contained in the RAM are erased.
The controller is located under the console of the dashboard and fastens to a board of a motor compartment.
For replacement of the controller you will need the screw-driver with a crosswise edge.
1. Disconnect a wire from the minus plug of the rechargeable battery.
2. Take away the fixing bracket …
3. … also disconnect a block of a plait of wires of system of injection of fuel from controller conclusions.
4. Turn out two nuts of hairpins of the controller …
5 … also remove the controller from the panel of its fastening.
6. Turn out three bolts of fastening of the panel of the controller and remove the controller panel.

So the controller removed from the car looks. Pay attention to its marking that when replacing to buy the controller with the same marking.

7. Install the controller and the panel of its fastening as it should be, the return to removal.