1997-2005 of release
Repair and car operation
+ Cars Subaru Forester
+ The maintenance instruction
+ Routine maintenance
+ The engine
+ Systems of cooling, heating
+ The power supply system and release
+ Engine electric equipment
- Control systems of the engine
System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions. Signals in management chains
ЕСМ - the general information, an estimation of a condition and replacement
Information gauges, the relay and actuation mechanisms - the general information
System of catching of fuel evaporations (EVAP)
System recycling the fulfilled gases (EGR)
System of operated ventilation картера (PCV)
The conductor of a jellied mouth of a fuel tank
The Katalitichesky converter - the general information, check of a condition and replacement
+ Gear change box
+ Coupling, трансмиссионная a line
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions. Signals in management chainsData on diagnostic devices
Check of serviceability of functioning of components of systems of injection and decrease in toxicity of the fulfilled gases is made by means of a universal digital measuring instrument (multimeter).
Use at diagnostics of considered systems of a digital multimeter with a high impedance essentially raises accuracy made in низковольтовом a range of measurements
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 мОм). 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 (9 ÷ 12), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, a l-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, automatic transmission, ABS, SRS special diagnostic scanners or testers with the certain cartridge, intended for work with system of onboard diagnostics of the second generation OBD II, special scanner Subaru Select Monitor (SSM) or the personal computer with a special cable and the program browser OBD (www.obd-2.com, www.obd-2.de) are applied.
Universal adapter K-L-line
Connection of the personal computer to a diagnostic socket
Universal adapter K-L-line (www.autoelectric.ru), serves for the coordination of signals of port RS-232 and interfaces ISO-9141 (K-line) and ALDL. The various cables necessary for diagnostics of concrete mark of the car can be connected To adapter sockets. The switches established in the adapter and indication elements allow to choose necessary operating modes and approximately to estimate work of target lines. So, the luminescence of a green light-emitting diode with marks L-line, testifies to connection of line L with the car case. The luminescence of a red light-emitting diode with marks K-line specifies in high potential which blinking of indicators is present during this moment on K.Pri's line of the established communication with the car can be imperceptible for an eye because of high speed of an exchange. Connection to the computer is made directly in 25-contact COM-port or with the help “Cable RS-232 25 конт. - 9 конт.” In a 9-contact CATFISH-PORT.
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 are put), to program anticreeping system and management blocks, to observe signals in car chains in real time.
II for diagnostics of your car you can download the free version of browser OBD also from our site arus.spb.ru
Reading written down in memory of system of self-diagnostics of codes of malfunctions on some models can be made also on the indicator “Check up the engine” on a control panel.
Appointment of conclusions of a diagnostic socket.
The general description of system OBD II
System OBD structure includes some the diagnostic devices making monitoring of separate parametres of systems of decrease of toxicity and fixing revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions. The system makes also check of gauges and actuation mechanisms, supervises vehicle service cycles, provides storing possibility even failures quickly arising in the course of work and clearing of the block of memory.
Models described in the present Management are equipped by system of onboard diagnostics (OBD). A system Basic element is the onboard processor, more often named the electronic module of management (ЕСМ), or the module of management of functioning of the power unit (РСМ). РСМ 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 the data arriving from information gauges and according to put in memory of the processor in base parametres, РСМ 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 memory of processor OBD-II is made by means of the special scanner connected to a 16-contact diagnostic socket of reading of a database, located under the panel of devices from the driver's party of the car.
Reading of codes of malfunctions
The information maintenance of categories of a code
At revealing of the malfunction repeating successively on two trips, РСМ gives out a command on inclusion of the control lamp built in in an instrument guard “Check up the engine”, named also the indicator of refusals.
Without starting the engine, include ignition, - a control lamp “Check up the engine” should light up, otherwise it is necessary to replace it, and to go out after engine start. The lamp can not die away for the reason of short closed stopper of a mouth of a fuel tank.
Having checked up serviceability of a condition of a lamp and the closed condition of a stopper of a mouth, again warm up the engine and switch off ignition. Close a test socket. Get the car and be passed 1 mines with a speed more than 10 km/hour, serially including all transfers. Stop, without switching off the engine. On 40 сек lift turns to 2000 in minute Consider blinking codes (address to Specifications).
Clearing of memory OBD
At entering of a code of malfunction in memory РСМ on an instrument guard of the car the control lamp “lights up Check up the engine”. The code remains written down in memory of the module.
For clearing of memory ЕСМ connect to system the scanner and choose in its menu function CLEARING COEDS (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), it is possible to disconnect from the battery a positive wire simply also.
Application of an oscillograph for supervision of signals in chains of control systems
Digital multimeters perfectly approach for check of electric chains being in a static condition, and also for fixing of slow changes of traced parametres. At carrying out of the dynamic checks which are carried out on the working engine, and also at revealing of the reasons sporadic failures by absolutely irreplaceable tool there is an oscillograph.
Some oscillographs allow to keep oscillograms in the built in module of memory with the subsequent conclusion of results to the press or their swapping to the carrier of the personal computer already in stationary conditions.
The oscillograph allows to observe periodic signals and to measure pressure, frequency, width (duration) of rectangular impulses, and also levels of slowly varying pressure.
The oscillograph can be used for:
Parametres of periodic signals
Each signal removed by means of an oscillograph can be described by means of the following key parametres:
Usually characteristics of the faulty device strongly differ from reference that allows the operator easily and quickly visually to reveal the refused component.
Alternating current signals - are analyzed amplitude, frequency and the signal form.
The frequency-modulated signals - are analyzed amplitude, frequency, the form of a signal and width of periodic impulses. Sources of similar signals are following devices:
The signals modulated on width of an impulse (ШИМ) - are analyzed amplitude, frequency, the form of a signal and porosity of periodic impulses. Sources of similar signals are following devices:
The coded sequence of rectangular impulses - the amplitude, frequency, the form of sequence of separate impulses are analyzed.
Interpretation of signals
The form of a signal given out by an oscillograph depends on set of various factors and can change appreciably. In a kind told before to start replacement of a suspected component in case of discrepancy of the form of the removed diagnostic signal with the reference oscillogram, it is necessary to analyse the received result carefully:
In chains of a direct current the amplitude of a signal is limited to pressure of a food. As an example it is possible to result a chain of system of stabilisation of turns of idling (IAC) which alarm pressure does not change in any way with change of turns of the engine.
In chains of an alternating current the amplitude of a signal already unequivocally depends on frequency of work of a source of a signal so, the amplitude of the signal which is given out by the gauge of position of a cranked shaft (CKP) will increase with increase of turns of the engine.
In a kind told if the amplitude of a signal removed by means of an oscillograph appears excessively low or high (up to trimming of top levels), it is enough to switch only a working range of the device, having passed to a corresponding scale of measurement.
Frequency of repetition of alarm impulses depends on working frequency of a source of signals.
The form of a removed signal can be edited and led to a kind convenient for the analysis by switching on an oscillograph of scale of time development of the image.
As already it was told above, for signal reduction to a legible kind it is enough to switch scale of time development of an oscillograph.
In certain cases characteristic changes of a signal appear developed mirror concerning reference dependences that speaks реверсивностью polarity of connection of a corresponding element and, in the absence of an interdiction for change of polarity of connection, can be ignored at the analysis.
Typical signals of components of control systems of the engine
Modern oscillographs are usually equipped only by two alarm wires in a compartment with a set various probeов, allowing to carry out device connection practically to any device.
The red wire is connected to a positive pole of an oscillograph and usually connected to the plug of the electronic module of management (ECM). The black wire should be connected to reliably earthed point (weight).
Management of structure of an air-fuel mix in modern automobile electronic systems of injection of fuel is carried out by timely updating of duration of opening of electromagnetic valves of injectors.
Duration of stay of injectors abroach is defined by duration developed by the module of management of the electric impulses submitted on an input of electromagnetic valves. Duration of impulses is measured in milliseconds and usually does not fall outside the limits a range 1 ÷ 14 мс.
Often on the oscillogram it is possible to observe also a series of the short pulsations following directly behind the initiating negative rectangular impulse and supporting the electromagnetic valve of an injector abroach, and also the sharp positive throw of pressure accompanying the moment of closing of the valve.
Serviceability of functioning ECM can be checked easily up by means of an oscillograph by visual supervision of changes of the form of an operating signal at a variation of working parametres of the engine. So, duration of impulses at проворачивании the engine on single turns should be a little above, than at unit work on low turns. Increase of turns of the engine should be accompanied by respective increase in time of stay of injectors abroach. The given dependence is especially well shown at opening throttle заслонки by short pressing a gas pedal.
At cold start the engine requires some enrichment of an air-fuel mix that is provided with automatic increase in duration of opening of injectors. In process of warming up duration of operating impulses on the oscillogram should be reduced continuously, gradually coming nearer to value typical for single turns.
In injection systems in which the injector of cold start is not applied, at cold start of the engine the additional operating impulses shown on the oscillogram in the form of pulsations of variable length are used.
In the table resulted more low typical dependence of duration of operating impulses of opening of injectors on a working condition of the engine is presented.
The electromagnetic valve of stabilisation of turns of idling (IAC)
In motor industry electromagnetic valves IAC of set of the various types which are giving out signals also of the various form are used.
The general distinctive feature of all valves is that fact that porosity of a signal should decrease with loading increase for the engine, connected with inclusion of additional consumers of the capacity causing fall of turns of idling.
If porosity of the oscillogram changes with loading increase, however at inclusion of consumers infringement of stability of turns of idling takes place, check up a condition of a chain of the electromagnetic valve, and also correctness given out ECM a command signal.
Usually in chains of stabilisation of turns of idling the 4-polar step-by-step electric motor which description is resulted more low is used. Check of 2-contact and 3-contact valves IAC is made in a similar manner, however oscillograms of alarm pressure given out by them are absolutely unlike.
The step-by-step electromotor, reacting on given out ECM a pulsing operating signal, makes step updating of turns of idling of the engine according to working temperature of a cooling liquid and current loading on the engine.
Levels of operating signals can be checked up by means of an oscillograph, measuring probe which is connected serially to each of four plugs of the step-by-step motor.
Warm up the engine to normal working temperature and leave its working on single turns.
For increase in loading at the engine include head headlights, air conditioner, or, - on models with the wheel hydraulic booster, - turn a steering wheel. Idling turns should fall to short time, however there and then again to be stabilised at the expense of valve IAC operation.
Compare the removed oscillogram with resulted on an illustration reference.
Ljambda-probe (the oxygen gauge)
If the removed signal is not wavy, and represents linear dependence, that, depending on pressure level, it testifies to excessive repauperization (0 ÷ 0.15), or reenrichment (0.6 ÷ 1) an air-fuel mix.
At insufficient image sharpness slightly knock on the block of cylinders around placing of the gauge of a detonation.
If to achieve unambiguity of the form of a signal it is not possible, replace gauge KS, or check up a condition of electroconducting of its chain.
Ignition signal on an amplifier exit
At increase in turns of the engine frequency of a signal should increase in direct ratio.
Non-uniformity of throws can be caused excessive resistance of a secondary winding, and also malfunction of condition ВВ of a wire of the coil or a candle wire.