Saab 9-5

since 1997 of release

Repair and car operation

Search of malfunctions - the general information and preliminary checks

Systems of ignition and a food are the interconnected components of a control system of the engine therefore some of its components can carry out also certain functions concerning functioning of a power supply system.

General information

Systems of ignition and a food have the general diagnostic system intended for preservation of codes of malfunctions (DTC) and carrying out diagnostics. At refusal identification the control unit writes down the corresponding DTC code representing some sequence of signals which can be считана by means of the special scanner in memory of the processor.

Reading of information which is storing in memory of ECM, in most cases allows to define the reasons of failures in operation of the engine of the car. The analysis of only a few information with application of the list of codes (see.) the refusal source at level of a concrete element, or a chain of its electroconducting allows to localize specifications.

Preliminary checks

If malfunction arose soon after performance of service of any knot, first of all, it is necessary to investigate carefully this knot and the components located in the neighbourhood, - is not excluded that the cause of failure is connected with elementary violation of quality of contact connection.

By search of causes of infringement of serviceability of functioning of the engine (for example, falling of the developed capacity) always it is meaningful to check a compression in cylinders. Watch also that replacement of air and fuel filters was made according to the maintenance schedule (see. Head of Control and routine maintenance of the car).

Do not forget to clear memory of the control unit after reading of codes of malfunctions and introduction of the corresponding corrections.

Open a cowl and check reliability of fixing of tips of wires on polar plugs of the battery, make sure of lack of signs of oxidation of terminal connections. In case of need make the appropriate measures on the debugging, the failed components replace. Study a condition of tires of grounding and their terminal connections not less attentively, - contact surfaces of the corresponding elements of weight (the power unit / body panels) should be absolutely pure and free from corrosion traces.

Attentively examine all visible electroconducting in an impellent compartment, check reliability of contact connections. Having strongly pronounced signs of damage electroconducting replace, having tracked correctness of laying of plaits; in case of need tighten weakened fixture of knots about which isolation frayed.

It is necessary to remember that current-carrying veins of electroconducting can appear damaged in the absence of signs of damage of isolation, - in a similar situation external survey will not give positive results. Similar damages can result from a pulling of wires, or at violation of routes of their laying.

To restore the damaged electroconducting it is possible by a vpaivaniye on a site of break of a shunting vein, - the soldering provides reliability of electric contact. For repair of isolation use an insulating tape, or plant on a wire a piece of a thermoshrinkable tube. The best (though not the cheapest) way of elimination of all interfaced to damage of electroconducting of refusals is replacement of the failed wire.

Having finished regenerative repair / having picked up replacement, track correctness of laying of the corresponding plaits, special attention giving to the sites of routes passing near warmed-up surfaces and moving components in an impellent compartment. Track reliability of fixing of plaits in all provided intermediate clamps.

Check a condition of all available terminal connections, check reliability of fastening of contact sockets of electroconducting. At identification on an internal surface of the socket of traces of corrosion (white or green deposits, a rust raid), and also at excessive pollution, remove the socket from the corresponding plug and carefully clear, having in case of need used special spray. Seriously damaged sockets are subject to replacement, in certain cases in a set with an electroconducting plait.

After cleaning of the socket of traces of corrosion fill it before installation to the place of preserving greasing.

On cars considered in the real Management the inductive sensor of provision of a cranked shaft (CKP) by means of which position VMT of the piston of the first cylinder is defined is used. Excessive pollution or a zapyleniye of the sensor can be at the bottom of ignition admissions.

Attentively examine hoses and tubes of all vacuum lines of an impellent compartment. Check reliability of a tightening of fixing collars, make sure of absence of deformations, cracks, cuts, stratifications and other physical damages of hoses and tubes. Attentively study shtutserny knots on existence of signs of violation of tightness. It is necessary to give special attention to a condition of the lines laid near keen edges. Losses of depression are usually accompanied by characteristic whistle at which identification it is necessary to grease a suspected site of a hose with soap solution, - it is possible to consider a source of leak found if when drawing solution stability of turns of the engine raises. Tighten weakened collars, replace the damaged lines.

Estimate a condition and check passableness of hoses of PCV system (see. Head of the Power supply system and production of the fulfilled gases). Excessive pollution or violation of passableness of hoses involves violation of stability of turns of the engine, especially idling.

Moving from a fuel tank to the fuel distributive highway (via the fuel filter) along fuel pipelines, attentively study a condition of fuel lines. Special attention give to places of a joint of tubes where cracks through which leaks start to develop more often are formed. The damaged sections of fuel lines replace.

Uncover an air purifier and check a condition of a filtering element. Excessively polluted filter is capable to increase considerably total aerodynamic resistance of an inlet air path that directly affects capacity developed by the engine. In case of need replace filtering element.

Start the engine and leave it working at single turns.

Moving from an air inlet to an air purifier and further - to the throttle case, make sure of lack of signs of development of leakages of air in an inlet path. For identification of sources of leaks it is possible to use soap solution again. Make necessary corrections.

Tire out the car on the lift and study a condition of components of system of release of OG. Make sure of lack of signs of development of leaks, - it is simplest to reveal thinnesses of a final path it is possible by a blockage of its exhaust outlet, - characteristic whistle and smoke will help to localize the damaged site. Tighten weakened collars / replace the failed sealing laying, replace the damaged sections.

At the final stage of check at the working engine serially pull contact sockets of its electroconducting, - change of kind of work of the engine will testify to bad quality of contact, - make necessary corrections, replace the failed sites of electroconducting.

If during carrying out preliminary checks to identify a cause of infringement of stability of operation of the engine it is not possible, the car should be driven away on HUNDRED for performance of more careful diagnostics with use of the special equipment.