10.8.3. Electronic control unit (controller)
EBU is located under the dashboard and represents the operating center of an electronic control system of the engine. 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 EBU:
– situation and frequency of rotation of a bent shaft;
– position of the camshaft;
– temperature of cooling liquid;
– temperature and pressure of the soaked-up air;
– provision of a butterfly valve;
– content of oxygen in the fulfilled gases;
– existence of a detonation in the engine;
– car speed;
– tension in onboard network of the car;
– request for turning on of the conditioner.
On the basis of the obtained information of EBU 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 fans;
– conditioner compressor coupling;
– system of diagnostics.
EBU includes output chains (nozzles, various relays and so forth) by their short circuit on "weight" via output transistors of the controller. The only exception – a chain of the relay of the fuel pump. The electrogasoline pump is powered via the power relay. In turn, a winding of the relay EBU by means of short circuit of one of conclusions to "weight" operates.
EBU is equipped with the built-in system of diagnostics. He can distinguish malfunctions in work of ESUD, warning about them the driver through a control lamp of "Check engine" (check the engine). Besides, EBU stores the diagnostic codes indicating malfunction of a concrete element of system and the nature of this malfunction to help experts with performing diagnostics and repair.
For data exchange with EBU the diagnostic socket close to the assembly block under the dashboard serves. The scanner for reading of information on the mistakes which are stored in memory of EBU for check of sensors and executive mechanisms in real time, for control of executive mechanisms, and also reprogramming of EBU is connected to the diagnostic socket.
In the controller there are following types of memory:
– programmable read-only memory (PROM);
– operational memory device (OMD);
– electrically reprogrammiruyemy memory device (ERPZU).
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 is non-volatile.
Operational Memory Device (OMD). It is EBU "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 also 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.
Electrically reprogrammiruyemy memory device (ERPZU). It is used for temporary storage of codes passwords of anticreeping system of the car (immobilizator). The codes passwords accepted by EBU from the control unit of an immobilizator are compared to the codes stored in ERPZU therefore launch of the engine is allowed or forbidden.
In ERPZU such operational parameters of the car as the general run of the car, the general fuel consumption and operating time of the engine register.
ERPZU registers also some violations of operation of the engine and car:
– operating time of the engine with an overheat;
– operating time of the engine on low-octane fuel;
– operating time of the engine with excess of the most admissible frequency of rotation;
– operating time of the engine with admissions of ignition of fuel-air mix which existence is indicated by a control lamp of a control system of the engine;
– operating time of the engine with the faulty sensor of a detonation;
– operating time of the engine with the faulty sensor of concentration of oxygen;
– time of the movement of the car with excess of most allowed speed in the period of a running in;
– time of the movement of the car with the faulty sensor of speed;
– the number of shutdowns of the rechargeable battery at the switched-on ignition lock.
ERPZU is non-volatile memory and can store information without giving of food on the controller.
The controller is located in the left part of a box of airinflow.
For replacement of EBU you will need the screw-driver with a flat edge.
1. Disconnect a wire from the minus plug of the rechargeable battery.
2. Having hooked the screw-driver, remove the guard covering the controller.
3. Wring out a latch of a clamping level of the controller...
6. Disconnect a block from the controller and take out the control unit from an airinflow box.
7. Establish the removed details as it should be, the return to removal.