Nissan Maxima QX

since 1993 of release

Repair and car operation

Check of a condition and replacement of the sensor of absolute pressure in the pipeline (MAR)

On models since 1996 вып. the sensor of absolute pressure in the pipeline complete with the MAR electromagnetic valve is used for tracking depth of depression in the inlet pipeline. Change of this parameter of rather barometric pressure grows out of changes of the current load of the engine and its turns. RSM uses signals arriving from the MAR sensor in the diagnostic purposes. At delivery by the module of management of tension on the MAR electromagnetic valve the last provides development of the vacuum signal switching the MAR sensor to measurement of barometric pressure. In the absence of tension on the valve the MAR sensor makes reading of depth of depression in the pipeline which any change will be transformed to the alarm tension right there transferred to RSM. The amplitude of a signal developed by the sensor can change in a range from 0.5 In at completely closed butterfly valve, to 5.0 In at completely open (low depth of depression). Also certain dependence of amplitude of a signal developed by the sensor on the barometric pressure defined by height of position of the car above sea level takes place. The sensor and the MAR electromagnetic valve are established on back (from transmission) an end face of the left (forward) head of cylinders. RSM distinguishes some types of violations of functioning of the sensor, to each of which OBD appropriates an individual code of malfunction.

CHECK

Performance described below procedure can lead to entering in memory of OBD of malfunction which will be highlighted by a control lamp “Check the engine”. On termination of check and the corresponding regenerative repair do not forget to clear memory of system (see. The section System of onboard diagnostics (OBD) - a principle of functioning and codes of malfunctions).

MAR sensor

PERFORMANCE ORDER

1. Disconnect from the MAR sensor a vacuum hose and connect to the last the vacuum gage. Start the engine on single turns, - about 5 seconds later the measuring instrument should register depression, otherwise check the vacuum hose connecting the sensor to the electromagnetic valve on existence of cracks and signs of violation of passableness. If a hose as it should be, it is necessary to make check of a condition of the electromagnetic valve. In the presence of depression pass to condition check actually the MAR sensor.
2. Disconnect from the MAR sensor electroconducting. Connect the voltmeter to plugs red (+) and black (-) wires on the socket. At the included ignition (the engine do not start) the measuring instrument should issue the indication in 5.0 In, otherwise check a chain condition on a site between the socket and RSM. If electroconducting and contact connections as it should be, the car has to be driven away on car repair shop for carrying out diagnostics of a condition of the module of management and performance of the corresponding regenerative repair.
3. Switch off ignition and connect to the sensor electroconducting. Connect positive щуп the fan to the plug of a white wire from a reverse side of the socket (for more details see. Head Onboard electric equipment), negative щуп earth on weight. Include ignition (the engine do not start), - tension in a range from 3.2 to 4.8 Century should take place.
4. Disconnect from the sensor a vacuum hose and instead of it connect the manual vacuum pump. Create on the sensor depression by depth about 203 mm Hg. The amplitude of alarm tension developed by the sensor should fall to value 1.0 ÷ 1.4 In, otherwise replace assembly.

Electromagnetic valve

PERFORMANCE ORDER

1. Disconnect a hose of a source of depression of the inlet pipeline from the MAR electromagnetic valve. Connect to a hose the vacuum gage. Start the engine on single turns, - the measuring instrument should register depression, otherwise check a hose condition on existence of cracks and signs of violation of passableness. If a hose as it should be, pass directly to check of a condition of the valve.
2. Disconnect from the MAR electromagnetic valve electroconducting and make sure available tension of the battery between two plugs of the socket at the included ignition (a distance do not start). If tension is absent, address to schemes of electric connections (see. Head Onboard electric equipment) also check the corresponding chain on existence of signs of breaks on a site between the assembly block of safety locks and the valve socket (first of all, naturally, it is necessary to check a condition of safety locks).

3. If tension of the battery takes place, remove the electromagnetic valve and pass to diagnostics of its condition out of the car. By means of pair of wires crossing points equipped with safety locks connect the valve to the 12-voltny power supply. At the moment of tension giving the valve should publish clearly distinguishable click, being accompanied opening of the air channel between unions A and V.Pri otsutstvii of tension should open the channel between unions A and Page. The faulty valve is subject to replacement.

And — To the MAR sensor
In — To an inlet air line
With — To a source of depression of the inlet pipeline

REPLACEMENT

PERFORMANCE ORDER

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 equipment introduction in action!

2. Disconnect electroconducting from the sensor and/or the MAR electromagnetic valve.
3. Turn out screws of fastening of the sensor and/or the MAR electromagnetic valve. Disconnect a vacuum hose (and) and remove the corresponding assembly.
4. Installation is made upside-down.