Honda Accord

1998-1999 of release

Repair and operation of the car

Поради риболовлі

Check of serviceability of a state and replacement of the oxygen sensor (l-probe)

The l-probe located in a final path of the engine traces the content of oxygen in a stream of the fulfilled gases. At contact of molecules_{O 2}with a sensitive element of a probe the sensor develops an amplitude signal in the range from 0.1 to 0.9 V, depending on concentration of oxygen. And, to value 0.1 B there corresponds the high contents_{O 2}(the grown poor mix), and to value 0.9 B - low (the enriched mix). RSM continuously controls the signal arriving from the oxygen sensor, in case of need giving out commands for correction of composition of air and fuel mix due to change of duration of opening of injectors of injection. The optimum ratio of components of gas mixture guaranteeing the minimum fuel consumption at the most effective functioning of the catalytic converter makes 14.7 parts of air on 1 part of fuel, - its module of management and tries to support constantly, being guided by information arriving from a l-probe. On the considered models of cars two oxygen sensors are used; the primary is located in a final collector of the engine, and secondary - below the catalytic converter. By comparison of level of the content of oxygen on sites of the final highway is higher and below the RSM catalytic converter defines also efficiency of functioning of the last.

It should be noted that the oxygen sensor is capable to develop alarm tension only being heated-up up to the normal working temperature (about 320 °C). While the sensor is in a cold state, RSM works in the mode of the OPENED CONTOUR.

If at heated-up up to the normal working temperature and/or the engine working within not less than two minutes the oxygen sensor develops a stable signal with an amplitude below 0.45 V (at turns not less than 1500 in a minute), the system of self-diagnostics brings the corresponding code of malfunction (P0131 or P0132) in memory of RSM. The corresponding code is brought also in case of detection of malfunction in a sensor heater chain (see the Section System of Onboard Diagnostics (OBD) - the principle of functioning and codes of malfunctions).

In case of violation of serviceability of functioning of a l-probe or its chain of RSM passes into the mode of the opened contour, ignoring information arriving from sensors and supporting composition of air and fuel mix at some set level providing sufficient efficiency of return of the engine.

Serviceability of functioning of the oxygen sensor depends on performance of set of some certain conditions:

a) Electric parameters: Stability of the amplitude signal of a low voltage developed by the sensor in big degree depends on quality of contact connections of a chain of a l-probe which should be checked first of all in case of problems;
b) Supply of external air: The design of a l-probe provides free circulation of external air in the sensor. At installation of a probe always check passability of air channels;
c) Working temperature: RSM starts reacting to information arriving from a l-probe only after the sensor is heated-up up to the normal working temperature (about 320 °C). It is necessary not to lose sight of this fact when checking serviceability of functioning of a probe;
d) Quality of fuel: Correct functioning of a l-probe becomes possible only on condition of application for gas station of the car of UNLEADED fuel!

In addition to the conditions listed in the previous paragraph at service of a l-probe it is necessary to observe some special precautionary measures:

a) The oxygen sensor is equipped tightly with the piece of an electrical wiring which is built in in it and equipped with the contact plug which attempts of a detachment can lead to an irreversible exit of the sensor out of operation;
b) Try not to allow hits in blinds of the sensor or its electric socket of dirt and greasing;
c) Do not use any solvents for cleaning of the oxygen sensor;
d) Handle a l-probe extremely carefully, do not drop it and try not to shake;
e) The silicone protective cover has to put on on the sensor strictly definitely not to be melted and not to break serviceability of functioning of a probe.

CHECK

PERFORMANCE ORDER

1. Find the electric socket of the sensor. From a reverse side of the socket enter the unbent office paper clip into a nest of contact of an alarm wire (the plug No. 1 [+]), enter the second paper clip into a nest of the plug No. 2 (weight). Connect the positive probe of the voltmeter to the first paper clip, negative connect to the paper clip entered into the grounding plug. Cock the parking brake, transfer the AT selector lever to situation "P", on models with RKPP choose neutral transfer. A car front also establish to Poddomkratta it on props.

2. Start the engine and start tracing changes of alarm tension of the oxygen sensor.

try not to touch to warmed by surfaces of system of production of the fulfilled gases.

Slower fluctuations of tension of a secondary l-probe are a consequence of operation of the catalytic converter as the connected atoms of oxygen in molecules of CO2 and H2O influence a sensitive element of a probe in much smaller degree, than atoms as a part of molecules of CO and NOX.

3. At the initial stage the cold sensor has to develop a constant signal with an amplitude of 0.1 ÷ 0.2 In (the mode of the opened contour). About two minutes later the engine will reach the normal working temperature and the indication of the sensor will start fluctuating ranging from 0.1 to 0.9 B (the mode of the closed contour). If the system does not pass into the mode of the closed contour, or passes with is inadmissible a big delay (the lazy sensor), replace a l-probe.
4. Check also serviceability of functioning of the heater of the oxygen sensor. Disunite the socket of an electrical wiring of a probe and connect an ohmmeter between heater plugs (the plug No. No. 3 and 4). Nominal resistance makes 10 ÷ 40 Ohm.
5. Check serviceability of giving of food for the heater. Disunite the electric socket and measure tension on it from a plait between the plug No. 4 and weight. At the included ignition (do not start the engine) the voltmeter has to fix battery tension. If food is absent, check a condition of an electrical wiring on a chain site between the main relay, RSM and the oxygen sensor.
6. At negative results of the listed above checks, replace a faulty l-probe.

REPLACEMENT

PERFORMANCE ORDER

The l-probe reversing on the cold engine can appear the extremely difficult in view of thermal compression of metal of a final collector / pipe of system of release. In order to avoid risk of damage of components before starting removal of the sensor warm up the engine during a couple of minutes - try not to burn about the warmed surfaces in the course of procedure performance.

1. Disconnect a negative wire from the battery.

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

2. The car also establish to Poddomkratta it on props.
3. Accurately disunite the socket of an electrical wiring of the oxygen sensor.

4. Accurately turn out a probe from a final collector (primary sensor) or assemblies of the catalytic converter (the secondary sensor).

5. Before a sensor vvorachivaniye into place grease its carving part with the anti-taking sealant (new sensors are usually already covered with the relevant structure).
6. Screw the sensor on the regular place and strongly tighten it.
7. Connect an electrical wiring.
8. Lower the car on the earth and make its trial runs. Check memory of the module of management for existence of codes of malfunctions.