E39 series BMW 5

since 1996-2001 of release

Repair and car operation

Description of system of onboard diagnostics

(In case of the equipment of your OBD II car on шильде under a cowl there should be a record "OBD II compliant" and there should be a 16-contact socket. As a rule, OBD II are equipped North American models, since 1996 of release and the European models, since 2000 of release)

The structure of OBD system includes some diagnostic devices making monitoring of separate parameters of systems of decrease in 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 sensors and actuation mechanisms, supervises vehicle service cycles, provides storing possibility even failures quickly arising in the course of work and cleaning of the block of memory.

Models described in the real Management are equipped with system of onboard diagnostics. 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 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. Data read-out of memory of the processor is made by means of the special scanner connected to the 16-contact diagnostic socket of reading of a database (DLC), located on the average console or to the 20-contact diagnostic socket located at the left in an impellent compartment.

In principle, reading written down in memory of system of self-diagnostics of codes of malfunctions can be made by means of a lamp “Check the engine”.

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.

Reading of codes of malfunctions

The DME codes (SAE J1979) are transferred by a 8-digit binary word (byte). Each category (bit) reflects result of check of a certain electric chain of a control system, and accepts value 0 - if the test passed, and 1 - if malfunction is found.

Example of information byte and value of its categories

Information contents of categories of the 5-digit SAE code

Type of P 0 3 8 0 from left to right:

1 category
   -  P power unit
   -  B body
   -  With the chassis
2 category code Source
   -  0 standard SAE
   -  1 set BMW
3 category System
   -  0 system as a whole
   -  1 podmeshivaniye of air (air/fuel induction)
   -  2 injections of fuel
   -  3rd system of ignition or ignition admissions
   -  4 additional control of release
   -  5th speed of the car and management х.х.
   -  6 entrance and target signals of the control unit
   -  7th transmission
4,5 categories Serial number of malfunction of a component or chain (00-99)

The black, 20-contact diagnostic X6002 socket is located under a cowl of an impellent compartment at the left (arrow)

Purpose of conclusions of the 20-contact diagnostic socket

Reading of codes of malfunctions

At detection of the malfunction repeating in a row on two 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 memory of system of self-diagnostics will not be cleared of the codes of the revealed malfunctions brought in it. Reading of codes of malfunctions in OBD system can be made by means of described above the devices connected to the diagnostic socket. Other ways are possible not on all models. The blinking code can be считан on a lamp “Check the engine”.