Toyota Land Cruiser 100 / Amazon, Lexus LX 470

Since 1997 of release

Repair and car operation

System of onboard diagnostics (OBD) – ринцип functioning and codes of malfunctions

Data on diagnostic devices

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 (internal resistance of the device makes 10 million Ohm). As the voltmeter is connected to a checked chain in parallel, accuracy of measurement by that above, than the smaller parasitic current will pass through actually device. The given factor is not essential at measurement concerning high values of pressure (9 – 12), 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.

With introduction in manufacture meeting the requirements of last legislations on preservation of the environment of system of onboard diagnostics of the second generation (OBD-II) input readers of a special design have started to be issued. Some manufacturers have adjusted release of the scanners intended for use by mechanics-fans in house conditions, – ask in shops of automobile accessories.

The general information

The scheme of an arrangement of components of control systems of the engine and decrease in toxicity of the fulfilled gases on models with engine V8

Electronic systems of injection and decrease in toxicity of the fulfilled gases in the course of the functioning at car operation are crossed with the various other systems which are responsible for efficiency of return of the engine. All listed systems include in the structure a set of information gauges and the electronic module of management (ЕСМ) (address to an illustration above).

This sort of systems can be compared on the structure to the central nervous system of a human body where the brain role plays the management module (ЕСМ), and as the nervous terminations information gauges act. Gauges send signals on ЕСМ which analyzes the arriving information and develops reciprocal commands on updating of corresponding working parametres.

Let's consider the specific example allowing more clearly to imagine a principle of functioning of system: built in in system of release the ljambda-probe continuously traces maintenance level About _{2 in a} stream of the fulfilled gases of the engine. If percentage of oxygen considerably deviates some entered into memory of system of control value, ЕСМ immediately receives the corresponding information and on the basis of its analysis develops a command on corresponding updating of duration of opening of injectors of fuel, carrying out thereby adjustment of structure of an air-fuel mix. Duration of the described procedural cycle makes fractions of a second that provides due efficiency of functioning of system. As a result, efficiency of return of the engine is constantly supported at the greatest possible level.

Reading of codes of malfunctions OBD-II

In system OBD-II five-place codes of the revealed malfunctions are brought in memory of the processor (ЕСМ).

It is necessary to notice that the system of onboard self-diagnostics is capable to find out not all possible refusals, – in case of need do not hesitate to address for consultations on firm car repair shops of company Toyota. During search of the reasons of decrease in efficiency of return of the engine, increase of the expense of fuel or level of toxicity of the fulfilled gases (the given infringements usually are not accompanied by operation of a control lamp «Check up the engine») it is necessary to make first of all all complex of standard checks about revealing of the reasons listed in Section, devoted to diagnostics of malfunctions of systems and car knots in introduction to the present Management and only after that to be switched to system OBD.

It is necessary to remember that use OBD-II demands from the operator of base knowledge in the field of automobile electronics, non-observance of safety measures at reference ЕСМ and other electronic components can lead to an irreversible exit of system out of operation.

In the table resulted more low the list of diagnostic codes OBD-II of the most typical refusals of system is presented. If to reveal and eliminate a cause of a failure independently it is not possible, the car should be driven away on a car repair shop for the purpose of carrying out of diagnostics with application of the special diagnostic equipment.

Clearing of memory OBD-II

For clearing of memory ЕСМ connect to system the scanner and in an apportion of its menu choose function «CLEARING CODES» («Removal of codes»). Further follow the instructions highlighted on the device, or at once for 30 seconds take from the nest in the assembly block safety lock EFI. Alternatively clearing of memory of system can be made by removal of a fusible insert (the main safety lock of system of onboard power supplies), the battery established near to the positive plug (the Onboard electric equipment see) (it is possible to disconnect simply also from the battery a positive wire).