1998-2003 of release

Repair and car operation

Lexus RX 300
+ Cars Lexus RX-300
+ Controls and operation receptions
+ Options and car routine maintenance
+ The engine
+ Systems of cooling of the engine, heating, ventilation and air conditioning
+ The power supply system and release of the fulfilled gases
- Systems of an electric equipment of the engine
   + Ignition and engine management systems
   - Diagnostics of systems of electronic control and the diagnostic equipment
      The general information
      Application of an oscillograph for supervision of signals in chains of control systems
   + Charge and start systems
+ Automatic transmission and interaxal differential
+ Transmissionnaja line
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Basic schemes of electric connections

Diagnostics of systems of electronic control and the diagnostic equipment

The general information

System of onboard self-diagnostics (OBD)

System OBD structure includes some the diagnostic devices making monitoring of separate parametres of systems of the car and fixing revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions.

Models described in the present Management are equipped by system of onboard diagnostics of the second generation (OBD II) which basic element is the onboard processor, more often named the electronic block of management (ECM).

ECM is a brain of a control system of the engine. The initial data arrives on the module from various information gauges and other electronic components (switches, the relay etc.). On the basis of the analysis of this data, and according to put in memory of the processor in base parametres, ECM develops commands on operation of various operating relays and actuation mechanisms, carrying out thereby updating of working parametres of the engine and providing peak efficiency of its return at the minimum expense of fuel.

Data read-out of system OBD II is made by means of the special scanner connected to a 16-contact diagnostic socket (DLC №3). By means of the same scanner clearing of memory of the processor is carried out also. Performance of procedures of reading of codes DTC and clearings of memory ECM will be reasonable to charge to experts HUNDRED.

Communication between ECM and DLC №3 is organised under standard ISO 9141-2. Contacts in DLC №3 are located according to standards SAE J1962 and ISO 9141-2.

Contacts of socket DLC №3
4 — Connection with the case
5 — the Case - an alarm conclusion
7 — Line K of the diagnostic data (ISO 9141-2)
15 — Line L of the diagnostic data (ISO 9141-2)
16 — Pressure of the battery through a safety lock (at any position of the lock of ignition)

Data on diagnostic devices

Check of serviceability of functioning of components of systems of injection and decrease in toxicity ОГ is made by means of a universal digital measuring instrument (multimeter). Use of a digital measuring instrument preferably for the several reasons. First, on analogue devices it is difficult enough (at times - it is impossible), to define result of the indication to within the 100-th and thousand shares while at inspection of the contours including in the structure electronic components, such accuracy takes on special significance. The second, the reason that fact is not less important that the internal contour of a digital multimeter, has high enough impedance. As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that above, than the smaller current will pass through actually device. The given factor is not essential at measurement concerning high values of pressure (912), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a ljambda-probe where it is a question of measurement of shares of volt.

Parallel supervision of parametres of signals, resistance and pressure in all chains of management is possible by means of a splitter included consistently in a socket of the block of engine management. Thus on the switched off, working engine or during car movement, measurement of parametres of signals on splitter plugs from what the conclusion about possible defects becomes is made.

For diagnostics of electronic systems of the engine, АТ, systems ABS, SRS and other special diagnostic scanners or testers with a certain cartridge (if it is provided), a universal cable and a socket can be applied. Besides, it is possible to apply the expensive specialised automobile diagnostic computer specially developed for full diagnostics of the majority of systems of modern cars to this purpose (for example, ADC2000 firms Launch HiTech). Also, it is possible to apply scanners and specialised diagnostic analyzers to this purpose, for example, FDS 2000, Bosch FSA 560 (, KTS500 (0 684 400 500) or the usual personal computer with the special adapter, a cable (for example, the complete set 1 687 001 439) and the established program browser OBD II.

Some scanners, besides usual operations of diagnostics, allow, at connection with the personal computer, to unpack stored in memory of the block of management basic schemes of an electric equipment (if those are put), to program anticreeping system, to observe signals in car chains in real time.