Subaru Forester

1997-2005 of release

Repair and operation of the car

Subaru Forester
+ Subaru Forester cars
+ Maintenance instruction
+ Routine maintenance
+ Engine
+ Cooling systems, heating
+ Power supply system and release
+ Engine electric equipment
- Control systems of the engine
   Specifications
   System of onboard diagnostics (OBD) - the principle of functioning and codes of malfunctions. Signals in chains of management
   ESM - the general information, assessment of a state and replacement
   Information sensors, the relay and actuation mechanisms - the general information
   System of catching of fuel evaporations (EVAP)
   System of recirculation of the fulfilled gases (EGR)
   System of the operated ventilation of a case (PCV)
   Conductor of a jellied mouth of the fuel tank
   The catalytic converter - the general information, check of a state and replacement
+ Gear shifting box
+ Coupling, transmission line
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

System of onboard diagnostics (OBD) - the principle of functioning and codes of malfunctions. Signals in chains of management

Data on diagnostic units

Check of serviceability of functioning of components of systems of injection and decrease in toxicity of the fulfilled gases is made by means of the universal digital measuring instrument (multimeter).

Use at diagnostics of the considered systems of a digital multimeter with a high impedance significantly increases the accuracy of the measurements performed in the low-volt range

Use of the digital measuring instrument is preferable for several reasons. First, on analog devices it is rather difficult (sometimes, it is impossible), to define result of the indication to within the 100-th and thousand shares while at inspection of the contours including electronic components in the structure, such accuracy is of particular importance. The second, not less important, the fact that the internal contour of a digital multimeter, has rather high impedance is the reason (internal resistance of the device makes 10 megohms). As the voltmeter is connected to the checked chain in parallel, the accuracy of measurement of subjects is higher, than smaller current will pass through actually device. This factor is not essential at measurement of rather high values of tension (9 ÷ 12 V), however becomes defining at diagnostics of the elements giving low-voltage signals, such as, for example, l-probe where it is about measurement of shares of volt.

Parallel observation of parameters of signals, resistance and tension in all chains of management is possible by means of the splitter included consistently in the socket of the control unit of the engine. At the same time on the switched-off, working engine or during the movement of the car, measurement of parameters of signals on splitter plugs is performed from what the conclusion about possible defects is drawn.

The special diagnostic scanners or testers with a certain cartridge intended for work with system of onboard diagnostics of the second generation of OBD II, the special Subaru Select Monitor (SSM) scanner or the personal computer with a special cable and the program as OBD browser are used to diagnostics of electronic systems of the engine, automatic transmission, ABS, SRS (www.obd-2.com, www.obd-2.de).

Universal K-L-line adapter

Connection of the personal computer to the diagnostic socket

The universal K-L-line (www.autoelectric.ru) adapter, serves for coordination of signals of RS-232 port and ISO-9141 interfaces (K-line) and ALDL. Various cables necessary for diagnostics of concrete make of the car can be connected to sockets of the adapter. The switches and elements of indication installed in the adapter allow to choose necessary operating modes and approximately to estimate work of output lines. So, the luminescence of a green light-emitting diode with L-line marking, demonstrates connection of the line L with the car case. The luminescence of a red light-emitting diode with marking of K-line indicates the high potential which is present at this moment at the line K. At the established connection with the car the blinking of indicators can be imperceptible for an eye because of the high speed of exchange. Connection to the computer is made directly to the 25-contact COM port or by means of "The RS-232 25 cable Comte. - 9 Comte." in 9-contact SOM port.

Some scanners, besides usual operations of diagnostics, allow to print out, at connection with the personal computer, the schematic diagrams of electric equipment which are stored in memory of the control unit (if are put), to program anticreeping system and control units, to observe signals in car chains in real time.

You can also download the free version of a browser of OBD II for diagnostics of your car from our website arus.spb.ru

Reading of the codes of malfunctions which are written down in memory of system of self-diagnostics on some models can be made also on the Check the Engine indicator on the control panel.

Purpose of conclusions of the diagnostic socket.

Diagnostic socket of system of onboard diagnostics of OBD II

conclusion No.

Appointment

1
Plus batteries. Energized at any position of the lock of ignition.

4
Signal from the control unit to Subaru Select Monitor (tester of diagnostics of Subaru)

5
Signal from Subaru Select Monitor to the control unit

6
Clock signal of Subaru Select Monitor

10
Line K, ISO 9141 CARB

12
The case - an alarm conclusion

13
Connection with the case

General description of the OBD II system

Several diagnostic devices making monitoring of separate parameters of systems of decrease in toxicity and fixing the revealed refusals in memory of the onboard processor in the form of individual codes of malfunctions are a part of the OBD system. The system makes also check of sensors and actuation mechanisms, controls vehicle service cycles, provides a possibility of storing even of the failures which are quickly arising in the course of work and cleaning of the block of memory.

The models described in the present manual are equipped with system of onboard diagnostics (OBD). A basic element of system is the onboard processor more often called by the electronic module of management (ESM), or the module of management of functioning of the power unit (RSM). RSM is a brain of a control system of the engine. Basic data arrive on the module from various information sensors and other electronic components (switches, the relay, etc.). On the basis of the analysis of the data arriving from information sensors and according to the basic parameters put in the processor memory, RSM develops commands for operation of various operating relays and actuation mechanisms, carrying out thereby adjustment of working parameters of the engine and providing maximum efficiency of its return at the minimum fuel consumption. Data read-out of the processor memory of OBD-II is made by means of the special scanner connected to the 16-contact diagnostic socket of reading of the database located under the dashboard from the driver's party of the car.

On separate models, reading of the codes of malfunctions which are written down in memory of system of self-diagnostics can be made by means of a lamp "Check the engine".

Special guarantee certificates with the extended validity extend to service of components of control systems of engine/decrease in toxicity of the fulfilled gases. It is not necessary to make attempts of independent performance of failure diagnostics of RSM or replacement of components of system, to an exit of terms of these obligations, - address specialists of company car repair shops.

Reading of codes of malfunctions

Information contents of categories of a code

Characteristic

Value

Look P 0 3 8 0 from left to right:

1
category

P
power unit

B
body

With
chassis

2 category
Code source

0
standard – the set SAE

1
expanded – the set Subaru

3 category
System

0
system in general

1
admixture of air (air/fuel induction)

2
fuel injection

3
system of ignition or admissions of ignition

4
additional control of release (auxillary emission
control)

5
speed of the car and management х.х.

6
entrance and output signals of the control unit

7
transmission

4,5 categories
Serial number of malfunction of a component or chain (00-99)

At detection of the malfunction repeating in a row on two trips, RSM issues the command for inclusion of the control lamp which is built in in an instrument guard "Check the engine", called also by the indicator of refusals.

The lamp will continue to burn until memory of system of self-diagnostics is not cleared of the codes of the revealed malfunctions brought in it.

If the lamp blinks with a frequency of 1 Hz - the system registered the admissions of ignition able to lead to damage of the catalytic converter.

At the included ignition, the stopped engine and the connected check mode socket - the lamp blinks with a frequency of 3 Hz.

Reading of codes of malfunctions in the OBD-II system can be made in various ways. The main way is reading by means of the devices described above connected to the diagnostic socket.

The socket of the mode of testing (1) and the 16-contact diagnostic socket of the database (DLC) located under the dashboard near a steering column.
The blinking code can be считан on a control lamp, after connection of the test socket, as shown in an illustration.

Without starting the engine, include ignition, - a control lamp "Check the engine" has to light up, otherwise it should be replaced and to go out after start of the engine. The lamp can not die away for the reason incompleteness of the closed stopper of a mouth of the fuel tank.

Having checked 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 the test socket. Start the car and be passed 1 min. with a speed more than 10 km/h, serially including all transfers. Stop, without switching off the engine. On 40 sec. lift turns till 2000 in min. Consider the blinking codes (address Specifications).

Cleaning of memory of OBD

When entering a code of malfunction in memory of RSM on an instrument guard of the car the control lamp "Lights up check the engine". The code remains written down in memory of the module.

For cleaning of memory of ESM connect the scanner to system and choose the CLEARING COEDS function (Removal of codes) in its menu. Further follow the instructions highlighted on the device or at once for 30 seconds take from the nest in the assembly block EFI safety lock. Alternatively cleaning of memory of system can be made by removal of a fusible insert (the main safety lock of system of onboard power supply), it is possible also just to disconnect a positive wire from the battery.

It is not desirable to make cleaning of memory of OBD by a detachment of a negative wire from the battery as it will lead to deleting of adjusting parameters of the engine and violation of stability of its turns for a short time after primary start.

If the stereosystem established on the car is equipped with a security code before disconnecting the battery make sure that you have the correct combination for input of the audio system in action!

Shutdown of the battery also leads to removal of settings of the receiver for favourite radio stations.

In order to avoid damage of ESM its shutdown and connection should be made only at the switched-off ignition!

Track that memory of system was cleared before installation on the engine of new components of systems of decrease in toxicity of the fulfilled gases. If before start of system after replacement of the failed information sensor not to make cleaning of memory of refusals, RSM will bring in it a new code of malfunction. Cleaning of memory allows the processor to make change-over on new parameters. At the same time the first 50 ÷ 20 minutes after primary start of the engine some violation of stability of its turns can take place.

Application of an oscillograph for observation of signals in chains of control systems

Digital multimeters perfectly are suitable for check of the electric chains which are in a static state, and also for fixing of slow changes of the traced parameters. When conducting the dynamic checks which are carried out on the working engine and also at identification of the reasons sporadic failures the oscillograph becomes absolutely irreplaceable tool.

Some oscillographs allow to keep oscillograms in the built-in module of memory with the subsequent conclusion of results to the press or their transfer to the carrier of the personal computer already in stationary conditions.

The oscillograph allows to observe periodic signals and to measure tension, frequency, width (duration) of rectangular impulses, and also levels of slowly changing tension.

The oscillograph can be used for: Identifications of failures of unstable character. Checks of results of the made corrections. Monitoring of activity of the l-probe of a control system of the engine equipped with the catalytic converter. The analysis of the signals developed by the l-probe which deviation of parameters from norm is unconditional the evidence of violation of serviceability of functioning of a control system in general - on the other hand, correctness of a form of the impulses given a lambda probe can serve as a reliable guarantee of lack of violations in a control system. Reliability and simplicity of operation of modern oscillographs do not demand any special special knowledge and experience from the operator. Interpretation of the obtained information can be easily made by elementary visual comparison of the oscillograms removed during check with given below typical for various sensors and actuation mechanisms of automobile control systems of temporary dependences.

Parameters of periodic signals

Characteristics of any periodic signal

Everyone, removed by means of an oscillograph signal can be described by means of the following key parameters:

Amplitude: A difference of the maximum and minimum tension (V) of a signal within the period; Period: Duration of a cycle of a signal (ms) Frequency: Number of cycles per second (Hz); Width: Duration of a rectangular impulse (ms, microsec); Porosity: The repetition period relation to width (In foreign terminology the return is applied porosity the parameter called by a running cycle, expressed in %) a signal Form: Sequence of rectangular impulses, single emissions, sinusoid, sawtooth impulses, etc.;

Usually characteristics of the faulty device strongly differ from reference that allows the operator easily and quickly visually to reveal the refused component.

Signals of a direct current - only signal tension is analyzed.

Signals of this sort are developed by the following devices:

Sensor of temperature of cooling liquid of the engine (ECT)

The sensor of temperature of the soaked-up air (IAT)

Sensor of provision of a butterfly valve (TPS)

The warmed-up l-probe (the oxygen sensor)

Measuring instrument of a volume expense of a stream of air (VAF)

Measuring instrument of mass of air (MAF)

Signals of alternating current - are analyzed amplitude, frequency and a form of a signal.

Sensor of a detonation (KS)

Inductive RPM meter of the engine

Frequency-modulated signals - are analyzed amplitude, frequency, a form of a signal and width of periodic impulses. Sources of similar signals are the following devices:

Inductive sensor of provision of a bent shaft (CKP)

Inductive sensor of position of the camshaft (CMP)

Inductive sensor of speed of the movement of the car (VSS)

The RPM meters working at Hall's effect and provisions of shaft

Optical RPM meters and provisions of shaft

Digital sensors of thermometric measurement of mass of air (MAF) and absolute pressure in the inlet pipeline (MAP)

The signals modulated on width of an impulse (ShIM) - are analyzed amplitude, frequency, a form of a signal and porosity of periodic impulses. Sources of similar signals are the following devices:

Fuel injectors

Devices of stabilization of turns of idling (IAC)

Primary winding of the coil of ignition

Electromagnetic valve of a purge of a coal adsorber (EVAP)

Valves of system of recirculation of the fulfilled gases (EGR)

The coded sequence of rectangular impulses - amplitude, frequency, a form of the sequence of separate impulses are analyzed.

Signals of this sort are generated by the module of memory of self-diagnostics of ECM of a control system of the engine. By the analysis of width and a form of impulses, and also calculation of their quantity in each of groups there can be schitana the codes of malfunctions which are stored in memory (on an illustration - a code 1223). Amplitude and a form of a signal remain constants, the written-down value will be given until memory of the module is not cleared.

Signal of a code of malfunction of the module of self-diagnostics of a control system of the engine (code 1223)

Interpretation of signals

The form of the signal given by an oscillograph depends on a set of various factors and can change considerably. In a look told before starting replacement of the suspected component in case of discrepancy of a form of the removed diagnostic signal with the reference oscillogram, it is necessary to analyse carefully received result:

Digital signal

Analog signal

Tension

Zero level of a reference signal cannot be considered as absolute basic value, - "zero" real signal, depending on concrete parameters of the checked chain, it can be shifted rather reference (see [1]) within a certain admissible range (see [2] and [1]).

Full amplitude of a signal depends on the supply voltage of the checked contour and also can vary rather reference value in certain limits (see [3] and [2]).

In chains of a direct current amplitude of a signal is limited to supply voltage. It is possible to give a chain of system of stabilization of turns of idling (IAC) which alarm tension does not change with change of turns of the engine in any way as an example.

In chains of alternating current signal amplitude already unambiguously depends on the frequency of work of a source of a signal, so, amplitude of the signal given by the sensor of provision of a bent shaft (CKP) will increase with increase in turns of the engine.

In a look told if amplitude of the signal removed by means of an oscillograph is excessively low or high (up to trimming of top levels), it is only enough to switch the working range of the device, having passed to the corresponding scale of measurement.

When checking the equipment of chains with electromagnetic management (for example, the IAC system) at power off tension throws (see [4]) can be observed which can be ignored quietly in the analysis of results of measurement.

It is not necessary to worry also at emergence of such deformations of the oscillogram as bevelling of the lower part of the forward front of rectangular impulses (see [5]) if, of course, the fact of a vypolazhivaniye of the front is not a sign of violation of serviceability of functioning of the checked component.

Frequency

Frequency of repetition of alarm impulses depends on the working frequency of a source of signals.

The form of the removed signal can be edited and brought to a look, convenient for the analysis, by switching on an oscillograph of scale of temporary development of the image.

At observation of signals in chains of alternating current temporary development of an oscillograph depends on the signal source frequency (see [3]) determined by engine turns.

As it was already told above, for reduction of a signal to a legible look it is enough to switch the scale of temporary development of an oscillograph.

In certain cases characteristic changes of a signal are developed specularly rather reference dependences that is explained by reversibility of polarity of connection of the corresponding element and, in the absence of the ban on change of polarity of connection, can be ignored in the analysis.

Typical signals of components of control systems of the engine

Modern oscillographs are usually equipped with only two alarm wires in a compartment with a set of the various probes allowing to carry out connection of the device practically to any device.

The red wire is connected to a positive pole of an oscillograph and is usually connected to the plug of the electronic module of management (ECM). The black wire should be connected to reliably grounded point (weight).

Injectors

Control of composition of air-fuel mix in modern automobile electronic systems of injection of fuel is exercised by timely adjustment of duration of opening of electromagnetic valves of injectors.

Duration of stay of injectors abroach is defined by duration of the electric impulses developed by the module of management given on an entrance of electromagnetic valves. Duration of impulses is measured in milliseconds and usually does not exceed the limit of the range of 1 ÷ 14 ms.

Impulse of management of opening of an injector of injection of fuel

Often on the oscillogram it is possible to observe also a series of the short pulsations following directly the initiating negative rectangular impulse and supporting the electromagnetic valve of an injector abroach, and also the sharp positive throw of tension accompanying the moment of closing of the valve.

Serviceability of functioning of ECM can be easily checked by means of an oscillograph by visual observation of changes of a form of the operating signal at a variation of working parameters of the engine. So, duration of impulses at an engine provorachivaniye on single turns has to be slightly higher, than during the operation of the unit on low turns. Increase in turns of the engine has to be followed by corresponding increase in time of stay of injectors abroach. This dependence is especially well shown when opening a butterfly valve by short pressing the accelerator pedal.

PERFORMANCE ORDER

1. By means of the thin probe from the set attached to an oscillograph connect a red wire of the device to the injector ECM plug of a control system of the engine. Reliably ground the probe of the second alarm wire (black) oscillograph.
2. Analyse a form of the signal engine which is read out during a provorachivaniya.
3. Having started the engine, check a form of the operating signal on single turns.
4. Having sharply pressed the accelerator pedal, lift the frequency of rotation of the engine to 3000 rpm, - duration of the operating impulses at the time of acceleration has to increase considerably, with the subsequent stabilization at the level equal, or slightly smaller peculiar to idling turns.
5. Bystry closing of a butterfly valve has to lead to the oscillogram flattening confirming the fact of an overshoot of injectors (for systems with fuel supply trim).

At cold start the engine needs some enrichment of air-fuel mix that is provided with automatic increase in duration of opening of injectors. In process of warming up duration of the operating impulses on the oscillogram has to be reduced continuously, gradually approaching value, typical for single turns.

In systems of injection in which the injector of cold start is not applied at cold start of the engine the additional operating impulses which are shown on the oscillogram in the form of pulsations of variable length are used.

Typical dependence of duration of the operating impulses of opening of injectors on the working condition of the engine is presented in the table given below.

Condition of the engine	Duration of the operating impulse, ms
Single turns	1.5 ÷ 5
2000 ÷ 3000 rpm	1.1 ÷ 3.5
Full gas	8.2 ÷ 3.5

Inductive sensors

The typical oscillogram of the signal developed by the inductive sensor

PERFORMANCE ORDER

1. Start the engine and compare the oscillogram removed from an exit of the inductive sensor with given on an illustration reference.
2. Increase in turns of the engine has to be followed by increase in amplitude of the pulse signal developed by the sensor.

Electromagnetic valve of stabilization of turns of idling (IAC)

In automotive industry electromagnetic IAC valves of a set of various types giving signals of also various form are used.

The common distinctive feature of all valves is the fact that porosity of a signal has to decrease with increase of the load of the engine connected with inclusion of the additional consumers of power causing decrease in turns of idling.

If porosity of the oscillogram changes with increase in loading, however at inclusion of consumers violation of stability of turns of idling takes place, check a condition of a chain of the electromagnetic valve, and also correctness of the given ECM of a command signal.

Usually in chains of stabilization of turns of idling the 4-polar step electric motor which description is given below is used. Check of 2-contact and 3-contact IAC valves is made in a similar manner, however oscillograms of the alarm tension given by them are absolutely unlike.

Step electric motor, reacting to the given ECM the pulsing operating signal, makes step correction of turns of idling of the engine according to the working temperature of cooling liquid and the current load of the engine.

Levels of the operating signals can be checked by means of an oscillograph which measuring probe is connected serially to each of four plugs of the step motor.

Warm up the engine up to the normal working temperature and leave it working at single turns.

For increase in load of the engine include head headlights, the air conditioner, or, - on models with the power steering, - turn a steering wheel. Turns of idling have to fall for a short time, however right there again be stabilized due to operation of the IAC valve.

Compare the removed oscillogram with given on an illustration reference.

The oscillogram of the operating signal of system of stabilization of turns of idling (IAC)

Lambda probe (oxygen sensor)

The oscillograms typical for the oxygen sensors of zirconium type which are most often used on cars in which basic tension 0.5B is not used are provided in the Section. Recently the increasing popularity is gained by titanic sensors which working range of a signal makes 0 ÷ 5 V, and the high level of tension is given at combustion of the grown poor mix, low, - enriched.

PERFORMANCE ORDER


1. Connect an oscillograph between the l-probe plug on ECM and weight. 2. Make sure that the engine is heated-up up to the normal working temperature.
3. Compare the oscillogram displayed the measuring instrument to the reference oscillogram of the signal given typical a lambda probe (the oxygen sensor) given on an illustration.

If the removed signal is not wavy, and represents linear dependence, then, depending on tension level, it demonstrates excessive reimpoverishment (0 ÷ 0.15 In), or reenrichment (0.6 ÷ 1 V) of air-fuel mix.

If on single turns of the engine the normal wavy signal takes place, try to squeeze out several times sharply gas loops, - fluctuations of a signal should not exceed the limit of the range of 0 ÷ 1 Century.

Increase in turns of the engine has to be followed by increase in amplitude of a signal, reduction - decrease.

Sensor of a detonation (KS)

PERFORMANCE ORDER

1. Connect an oscillograph between the plug of the sensor of a detonation of ECM and weight.
2. Make sure that the engine is heated-up up to the normal working temperature.

3. Sharply squeeze out the accelerator pedal and compare a form of the removed signal of alternating current to the reference oscillogram of the signal given by the typical sensor of a detonation (KS).

At insufficient image sharpness slightly knock on the block of cylinders around placement of the sensor of a detonation.

If it is not possible to achieve unambiguity of a form of a signal, replace the KS sensor, or check a condition of an electrical wiring of its chain.

Ignition signal at the exit of the amplifier

PERFORMANCE ORDER

1. Connect an oscillograph between the plug of the amplifier of ignition of ECM and weight.
2. Warm up the engine up to the normal working temperature and leave it working at single turns.

3. The sequence of rectangular impulses of a direct current has to be given for the screen of an oscillograph. Compare a form of the accepted signal to the reference oscillogram of the operating signal of the amplifier of ignition, paying close attention to coincidence of such parameters as amplitude, the frequency and a form of impulses.

At increase in turns of the engine the frequency of a signal has to increase in direct ratio.

Primary winding of the coil of ignition

The oscillogram of a signal on the plug of primary winding of the coil of ignition

PERFORMANCE ORDER

1. Connect an oscillograph between the plug of the coil of ignition of ECM and weight.
2. Warm up the engine up to the normal working temperature and leave it working at single turns.

3. Compare a form of the accepted signal to the yetalonny oscillogram of the operating signal of the amplifier of ignition, - positive throws of tension have to have constant amplitude.

Unevenness of throws can be caused by the excessive resistance of a secondary winding, and also malfunction of a condition of VV of a wire of the coil or a candle wire.