The device, service, Nissan Maxima QX repair - System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions//Maxim's Nissan (from 1993 g) accessories-sale.ru

Nissan Maxima QX

since 1993 of release

Repair and car operation



Nissan Maxima QX
+ Nissan Maxima brand Cars
+ Maintenance instruction
+ Settings and routine maintenance
+ Engine
+ Systems of cooling, heating
+ Power supply system and release
+ engine Electric equipment
- Control systems of the engine
   General information
   System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions
   Removal and RSM installation
   Check of serviceability of a condition, replacement and adjustment of the sensor of provision of a butterfly valve (TPS)
   Check of a condition and replacement of the sensor of measurement of weight of an air stream (MAF)
   Check of a condition and replacement of the sensor of absolute pressure in the pipeline (MAR)
   Check of a condition and replacement of the sensor of temperature of soaked-up air (IAT)
   Check of a condition and replacement of the sensor of temperature of cooling liquid of the engine (eats)
   Check of a condition and replacement of the sensor of provision of a cranked shaft (SKR)
   Check of a condition and replacement of the sensor of provision of a camshaft (SMR)
   Check of a condition and replacement of the sensor switch of pressure in system of hydrostrengthening of a wheel (PSP)
   Check of a condition and replacement of the oxygen sensor (l-probe)
   Check of a condition and replacement of the sensor of a detonation
   Check of a condition and replacement of the sensor of temperature of fuel of speed of movement of the car (VSS)
   Check of a condition and replacement of the sensor of speed of movement of the car (VSS)
   Check of a condition and replacement of components of system of stabilization of turns of idling
   Control system of functioning of the capacity valve
   System of operated ventilation of a case (PCV)
   System of a retsirkulyatsiya of the fulfilled gases (EGR) - the general information, check of a condition and replacement of components
   System of catching of fuel evaporations (EVAP) - the general information, check of a condition and replacement of components
   The catalytic converter - the general information, check of a condition and replacement
+ Transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
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System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions

Data 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 of a digital measuring instrument preferably 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 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 rather high 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 is higher, than the smaller parasitic current will pass through actually device. This factor is not essential at measurement of rather high values of tension (9 ÷ 12 In), however there is defining at diagnostics of elements giving out low-voltage signals, such, as, for example, an oxygen sensor where it is a question of measurement of shares of volt.

The most convenient devices for diagnostics of control systems by the engine of modern models of cars are manual input readers of skanerny type. Scanners of the first generation serve for reading of codes of malfunctions of OBD-I systems. Before application the input reader should be checked on compliance of model and year of release of the checked car. Some scanners are multipurpose, at the expense of possibility of change of a cartridge depending on model of the diagnosed car (Ford, GM, Chrysler, etc.), others are adhered to requirements of the regional authorities and intended for use in certain regions of the world (Europe, Asia, the USA etc.).


With introduction in production meeting the requirements of the last legislations on environmental protection of system of onboard diagnostics of the second generation (OBD-II) input readers of a special design started to be issued. Some producers adjusted release of the scanners intended for use by amateur mechanics in house conditions, - ask in shops of automobile accessories.

The scanners of other type intended for reading from memory of the onboard processor by direct connection to the diagnostic socket of the main plait of electroconducting of the car are issued also.


General description of OBD system

All models described in the real Management are equipped with system of onboard diagnostics (OBD). On models 1993 and 1994 of вып. the OBD-I system is applied, since 1995 all cars began to be completed with systems of diagnostics of the second generation (OBD-II).

Basic element of both systems is the onboard processor more often called by the electronic 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 data arriving from information sensors and according to put in memory of the processor in base parameters, 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.

On service of components of control systems of engine/decrease in toxicity of the fulfilled gases special guarantee certificates with the prolonged validity period extend. It is not necessary to undertake attempts of independent performance of problem diagnostics of RSM or replacement of components of system, to an exit of terms of these obligations, - address to specialists of firm car repair shops of the Toyota company.

Information sensors

The sensor of provision of a camshaft (SMR) - the Sensor develops information signals on the basis of which analysis of RSM defines the current phase of a gazoraspredeleniye and frequency of rotation of the engine, using received information at management of sequence of injection and ignition of an air and fuel mix in combustion chambers.

The sensor (and) the provision of a cranked shaft (SKR) - On all models since 1995 вып. two SKR sensors whereas on earlier models one such sensor was applied only are used. Signals arriving from sensors are used by RSM as basic at definition of turns of the engine and positions VMT of the piston of each of cylinders. On the basis of received information of RSM exercises administration of sequence of injection and ignition of an air and fuel mix in combustion chambers. In OBD-II systems signals developed by SKR sensors are used also at problem diagnostics of the power unit.

The sensor of temperature of cooling liquid of the engine (eats) - on the basis of information of RSM arriving from the sensor carries out necessary corrections of structure of an air and fuel mix and a corner of an advancing of ignition, and also supervises EGR system work.
The sensor of temperature of EGR - information Arriving from the sensor is used at determination of intensity of a retsirkulyatsiya of the fulfilled gases to the reception highway of the engine.

The sensor of temperature of fuel - RSM uses information issued by the sensor at problem diagnostics of components of system.

The sensor of temperature of soaked-up air (IAT) - RSM uses information arriving from the IAT sensor at adjustments of parameters of injection, installations of a corner of an advancing of ignition and at management of EGR system functioning.

The detonation sensor - the Sensor represents a piezoelement reacting to change of intensity of vibrations of the engine. On the basis of the analysis of information of RSM arriving from the sensor carries out corrections of a corner of an advancing of ignition for the purpose of timely elimination arising in chambers of combustion of a detonation of the air and fuel mix fraught with premature wear of internal components of the engine.

The sensor of absolute pressure in the pipeline (MAR) (model since 1996 вып.) - The sensor supervises variations of depth of depression in the inlet pipeline, connected with changes of turns of a cranked shaft and load of the engine, and will transform received information to a peak signal. Information arriving from the sensor is used by the management module at engine problem diagnostics.

The measuring instrument of weight of air (MAF) - the MAF Sensor defines volume and weight parameters of an air stream arriving in the inlet pipeline. As a sensitive element in the sensor the filament is used. RSM uses information delivered by MAR and IAT sensors at thin adjustments of parameters of injection.

The oxygen sensor (l-probe) - the Sensor develops a signal which amplitude depends on a ratio of amount of oxygen (About 2), the engine containing in fulfilled gases and external air. On the basis of information of RSM arriving from the sensor defines parameters of an air and fuel mix, in due time carrying out its enrichment or pauperization.

The sensor switch of pressure of working liquid of system of hydrostrengthening of a wheel (PSP) - on the basis of information of RSM arriving from the PSP sensor switch provides increase of turns of idling (at the expense of IAC valve operation) for the purpose of compensation of increasing loads of the engine, connected with functioning of the steering hydraulic booster at commission of maneuvers.

The sensor of provision of a butterfly valve (TPS) - the Sensor is located on the case of a throttle and connected to a butterfly valve axis. By amplitude of given-out TPS of a signal of RSM determines a corner of opening of a butterfly valve (copes the driver from a gas pedal) and as appropriate corrects supply of fuel to inlet ports of chambers of combustion. Failure of the sensor, or weakening of its fastening leads to interruptions of injection and violations of stability of turns of idling.

The sensor of speed of movement of the car (VSS) - As appears from its name, the sensor informs the processor on the current speed of movement of the car.

Other, controllable RSM parameters - Besides given out by the sensors listed above on RSM also additional information on functioning of various knots and the systems defining performance data of the engine arrives. To number other, systems and knots, management of which functioning carries out RSM, the following belongs:

a) Air central air;
b) ABS;
c) Storage battery (target tension);
d) EVAP system;
e) Ignition switch;
f) Sensor switch of permission of start;
g) Grounding chains;
h) Control system of transmission functioning.

Actuation mechanisms


The relay of management of functioning of the coupling of coupling To/in - RSM carries out To/in compressor shutdown during intensive acceleration.

Control lamp “Check the engine” - RSM makes inclusion of this control lamp at emergence of refusals of functioning of a control system by the engine.

The relay of management of functioning of fans of system of cooling - RSM exercises administration of functioning of fans of system of cooling on the basis of the analysis of the signals arriving from the sensor of temperature of cooling liquid.

Vacuum electromagnetic valves of management of EGR - On models till 1999 вып. RSM operates extent of opening of the vacuum EGR valve via the special intermediate electromagnetic valve.

The EGR valve - On models of 1999 вып. RSM exercises administration of a stream of a retsirkulyatsiya of the fulfilled gases via the electronic EGR valve.

The valve of a purge of a coal adsorber - This electromagnetic valve, working at the command of RSM, carries out a purge of a coal adsorber of EVAP system, deducing the fuel evaporations which have accumulated in it to the inlet highway of the engine.

The electromagnetic valve of management of turns of fast idling - This valve is applied on models since 1995 вып. also serves for increase in turns of idling in cold weather. In fact this valve carries out a role of an air zaslonka on carburetor models.

The forward support of a suspension bracket of the power unit - On the RSM some models supervises also rigidity of a forward support of the engine depending on speed of movement of the car. Minimization of vibrations is carried out by a choice of one of two installations of a support.

Injectors of injection of fuel - RSM provides individual inclusion of each of injectors according to an ignition established order. Besides, the module supervises duration of opening of the injectors, defined in the width of an operating impulse measured in milliseconds and defining amount of fuel injected into the cylinder. More detailed information on a principle of functioning of system of injection, replacement and service of injectors is provided in Head of the Power supply system and release.

The relay of the fuel pump - the Relay is activated by the management module at an ignition key povorachivaniye in the situation START/RUN. At inclusion of ignition of the relay carries out food giving on a gasoline pump which provides pressure lifting in a path of a power supply system of the car. More detailed information on location and a principle of functioning of the relay is provided in Heads Onboard electric equipment and Power supply systems and release.

The valve of stabilization of turns of idling (IAC) - the IAC Valve carries out a dosage of amount of the air which is restarted up bypassing a butterfly valve when the last is closed, or occupies the provision of idling. Opening of the valve and formation of a rezultiruyushchy air stream RSM operates.

The heater of the oxygen sensor - Control of functioning of this device carries out RSM. The heater makes a fast warming up of a l-probe to normal working temperature.

The power transistor - the Transistor carries out strengthening of a signal of the ignition developed by RSM and in the fullness of time makes instant grounding on mass of primary contour of system of ignition that causes generation of VV of the signal which is given out by the coil (ами) in a secondary chain of system is direct on spark plugs (for more details see. Head engine Electric equipment).

Electromagnet of management of functioning of the valve of capacity - On models 1993 and 1994 of вып. management of functioning of the valve of capacity carries out RSM by means of a special electromagnet.

The module of management of functioning of transmission (TSM) - TSM, being the module of management separate of RSM, receives signals from various information sensors, such as VSS, the sensor switch of permission of start, the sensor of turns of a shaft of the turbine, TPS, SMR, etc., and uses accepted data at definition of the moment of switching of transfer of AT demanded pressure in a path and the moment of blocking of the converter of rotation.

Reading of codes of malfunctions

At detection of the malfunction repeating in a row in spirit trips, RSM gives out command for inclusion of the control lamp built in in an instrument guard “Check the engine”, called also the indicator of refusals. The lamp will continue to burn until then, violation will not disappear, and will not be shown during three and more trips.

Reading of codes of malfunctions in OBD-II system can be made in two ways. In the first case it is necessary to provide access to RSM for the purpose of selector switching on highlighting of codes by means of diagnostic lamps / a control lamp “Check the engine”. RSM should be removed from the basic arm (without disconnecting electroconducting) and to operate according to the instructions provided below.


Models 1993 and 1994 of вып.


a) Include ignition (without starting the engine). A control lamp “Check the engine” on the dashboard should remain included that confirms food delivery on it from RSM and serviceability of the lamp.

 Violation of an order described below procedure can lead to casual cleaning of memory of RSM!


b) By means of a screw-driver turn the selector on RSM wall against the stop clockwise. Diagnostic lamps should start to blink, - after three gleams turn the selector against the stop counter-clockwise;
c) Attentively watch functioning of diagnostic lamps. The red light-emitting diode serves for highlighting of the first figure of a code of the malfunction, the second figure of a code is highlighted by the green diode. For example, the code (TPS chain) 43 will look as follows: four gleams of the red diode, then three gleams green. The code 55 highlighting testifies to absence of the violations revealed by system (see below in the present Section the card of codes of malfunctions);
d) At repeated inclusion of ignition after switching off it in the course of reading of codes the system automatically cancels results of previous search and procedure of reading it is necessary to begin anew. Remark: Engine start automatically blocks access to self-diagnostics system.

Models since 1995 вып.


a) Include ignition (without starting the engine). A control lamp “Check the engine” on the dashboard should remain included that confirms food delivery on it from RSM and serviceability of the lamp.

 Violation of an order described below procedure can lead to casual cleaning of memory of RSM!


b) By means of a screw-driver turn the selector on RSM wall against the stop clockwise. Diagnostic lamps should start to blink, - after three gleams turn the selector against the stop counter-clockwise;
c) Attentively watch functioning of a control lamp “Check the engine”. The lamp will highlight the first figure of a code a series long (approximately on 0.6 c) gleams, then, after a 2-second pause, will start highlighting of the second figure of a code in the form of a series short (on 0.3 c) gleams. For the purpose of definition of the highlighted code write down quantity of gleams of each series, so, the code 0403 (TPS chain) will look as follows: 4 long gleams, then, after a pause, three short. The code 0505 highlighting testifies to absence of the violations revealed by system (see below in the present Section the card of codes of malfunctions);
d) At repeated inclusion for zhiganiye after switching off it in the course of reading of codes the system automatically cancels results of previous search and procedure of reading it is necessary to begin anew. Remark: Engine start automatically blocks access to self-diagnostics system.

The second method means use of the special scanner, and is applicable only on the models equipped with OBD-II system (since 1995 вып.). with the help the scanner can be made deeper diagnostics of a condition of the engine and a thin assessment of its working parameters. Besides, the scanner allows to make reading of the data frozen by OBD system at the moment of emergence of unstable refusal.

 When using the scanner other form of record of codes is used, excellent from applied when reading by means of a control lamp “Check the engine”. In this case the type P0 or Р1 prefix (see the corresponding section of the table of the card of codes) is used. In the absence of near at hand scanner diagnostics of unstable violations of a control system of the engine can be made only in the conditions of a car-care center workshop.


Cleaning of memory ESM/RSM

After the violations revealed in the course of diagnostics will be eliminated, it is necessary to clear memory of RSM of the codes of malfunctions written down in it.

 It is not necessary to make memory cleaning by a detachment of a negative wire from the battery, is will lead also to loss of base parameters and violation of stability of turns of idling at first after engine start.


 When using scanner in OBD-II systems it is necessary to transfer the device to the CLEARING CODES mode and to operate according to instructions of manufacturers.


Models 1993 and 1994 of вып.

a) Consider the systems written down in memory codes of malfunctions;
b) Wait not less than two seconds, then turn the selector on RSM wall against the stop clockwise, - light-emitting diodes should start to blink;
c) After four gleams of diodes turn the selector against the stop counter-clockwise;
d) Switch off ignition.

Models since 1995 вып.


a) Consider the systems written down in memory codes of malfunctions;
b) Wait not less than two seconds, then turn the selector on RSM wall against the stop clockwise;
c) Wait yet less than two seconds and turn the selector against the stop counter-clockwise;
d) Switch off ignition.

Cleaning of memory should be made always before the first start of the engine after replacement of components of a control system with the engine. If in memory of the module the code of malfunction any of information sensors if after performance of replacement of the failed component to make engine start without memory cleaning was written down, the old code will remain in force and the system will be switched in a mode of base installations, having excluded the new sensor from among working components.

 Within the first 15 ÷ 20 seconds after the first start turns of the engine can remain unstable that is connected with restoration by the processor of performance data.


Identification of codes of malfunctions of system of an uparvleniye by the engine


The full map of possible codes of malfunctions is given in Specifications, not all from which can take place for a concrete complete set of the car.