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Nissan Maxima QXsince 1993 releaseRepair and operation of the car |
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Nissan Maxima QX + Cars of the Nissan Maxima brand + Maintenance instruction + Settings and routine maintenance + Engine + Cooling systems, heating + Power supply system and release + Engine electric equipment + Control systems of the engine + Transmission + Coupling and power shafts - Brake system General information System of anti-blocking of brakes (ABS) - the general information and codes of malfunctions Replacement of brake shoes of disk brake mechanisms Removal and installation of supports of disk brake mechanisms Check of a state, removal and installation of a brake disk Replacement of boots of drum brake mechanisms of back wheels Removal and installation of wheel cylinders Removal and installation of the main brake cylinder Replacement of the dosing valve regulator Check of a state and replacement of brake lines and hoses Pumping of the brake system Check of serviceability of functioning/tightness, replacement and adjustment of the vacuum amplifier of brakes Adjustment of the parking brake Replacement of a cable(s) of the drive of the parking brake Adjustment of a pedal of a foot brake Check of serviceability of functioning and replacement of the sensor switch of stoplights + Suspension bracket and steering + Body + Onboard electric equipment |
System of anti-blocking of brakes (ABS) - the general information and codes of malfunctions Hydraulic scheme of system of anti-blocking of brakesGeneral information When the vehicle is equipped with the brake system of usual type, sharp squeezing of a pedal of a foot brake leads to blocking of wheels. At the same time coupling of a protector with a paving is broken, and the car can start to skid, losing controllability. The system of anti-blocking of brakes (ABS) prevents premature blocking of wheels, continuously operating the speed of their rotation during braking due to modulations of pressure of hydraulic liquid in each of brake mechanisms. The principle of functioning of system is rather simple. Each of wheels is equipped with the individual RPM meter. The sensor consists of a rotor (a ring with the teeth which are evenly located on its perimeter) and a sensitive element in the form of the podmagnichenny coil. The sensitive element of the sensor fixes the moments of passing of rotor teeths by it and will transform the obtained information to the electric signals which are continuously transferred to ECU ABS. By results of processing of the arriving signals the control unit obtains information on the relative speed of rotation of each of wheels. While all four wheels rotate with an identical frequency, ABS stays in a passive state. As soon as any of wheels begins to be blocked, ECU fixes change of the entering signal and develops the command for operation of the modulator which is instantly dumping pressure of hydraulic liquid in the brake mechanism of the corresponding wheel. As soon as normal rotation of a wheel is restored, the processor stops functioning of the modulator. Actually the scheme of functioning of ABS is much more difficult, than it can seem therefore authors of the present manual do not recommend to owners of cars to make attempts of independent performance of repair of system. In case of malfunctions it will be most reasonable to address specialists of car service. The function chart explaining the principle of action of a hydraulic part of ABS is given in an illustration for reference. ABS components Pressure modulator The modulator consists of the electrodriving hydraulic pump, and three electromagnetic valves switches (two left and right lobbies and back). The electric pump provides supply of hydraulic liquid in tanks and the modulator controlling process of changes of pressure in contours of the brake system. The pump is placed in the general casing with assembly of the modulator. Electromagnetic valves switches play a role of actuation mechanisms, actually and providing the required modulations of pressure in a hydraulic path of the brake system during ABS functioning. Wheel sensors Special sensors which equipped car wheels when passing by their sensitive elements of teeths of the rotating rotors develop a frequent comb of electric impulses. The analog amplitude signal of the corresponding parameters arrives on the control unit (ECU) of ABS which will transform it to a digital form and on the basis of the analysis of the accepted information determines the frequency of rotation of each of wheels. Forward wheel sensors fasten on rotary fists in close proximity to the external CV JOINTS of rotors pressed in assemblies. Sensors of back wheels of a pribolchena to holders of stupichny assemblies whereas rotors are built in naves. Electronic control unit (ECU) of ABS The electronic control unit which is often called also by the processor is established in the luggage compartment of the car (models 1993 and 1994 of of the issue), or under a forward overlay of a threshold of a driver's door (model since 1995 by the issue). ECU, playing a role of the think-tank of system, accepts information arriving from wheel sensors and on the basis of its analysis exercises control of modulations of pressure in hydraulic paths of brake mechanisms of each of wheels, preventing their premature blocking. The processor continues to function and in the course of the normal movement of the vehicle, constantly controlling serviceability of a condition of the ABS components. Every time at start of the engine occurs short-term inclusion of a control lamp of ABS in an instrument guard of the car. The first diagnostic survey of a condition of the ABS components is carried out by the control unit when the speed of the movement of the vehicle reaches 6.4 km/h (4 miles/h). poll can be followed by a weak mechanical sound which should not attach significance. In case of identification of malfunctions of ECU provides inclusion of a control lamp of ABS, at the same time in the processor memory the corresponding code of malfunction which reading will allow to define further a refusal source is brought. Diagnostics and recovery repair At identification by the processor of malfunctions in system in an instrument guard lights up and remains to ABS included a control lamp. Diagnostics of malfunctions of anti-blocking system is among enough difficult procedures and authors of the present manual do not recommend to make it in house conditions. Nevertheless, it is possible to allocate a number of the elementary checks which can be quite successfully made by own forces of the owner of the car and allow to define qualitatively a cause of failure (see further). Models 1993 and 1994 of of the issue. a) Accelerate the car to 32 km/h (20 miles/h) and keep this speed of the movement within not less than one minute; b) Stop the movement, however you do not suppress the engine; c) Open the luggage compartment and count quantity of gleams of the control lamp of ABS which is built in in assembly of the control unit (ECU) on a light-emitting diode. In the presence in the processor memory of codes of malfunctions the control lamp will give series of continuous gleams with pauses on 5-10 seconds between them; d) Interpretation of the codes highlighted by a control lamp is given in the explanatory card (see below). e) Kill the engine. Models since 1995 of the issue. a) Accelerate the car to 32 km/h (20 miles/h) and keep this speed of the movement within not less than one minute; b) Stop the movement and kill the engine; c) Ground the plug L of the diagnostic DLC socket; d) Turn the ignition key in position of ON; e) 3.6 seconds later the control lamp of ABS will begin to highlight the two-digit codes of malfunctions of system which are stored in the processor memory. Each figure of a code is defined by a series short (for 0.4 seconds) the gleams of a lamp divided among themselves by pauses of the same duration, the second figure is separated from the first by a pause lasting 1.6 seconds. The moment of the beginning of reading is noted by delivery of a code 12 (one gleam, a pause, two gleams). Then again the pause after which the lamp begins to highlight the codes which are stored in memory of the control unit follows long (3.6 seconds). f) Interpretation of the codes highlighted by a control lamp is given in the explanatory card (see below).
a) Make sure of correctness of level of hydraulic liquid in the GTTs tank; b) Check a condition of contact connections of the corresponding electric chains; c) Check a condition of safety locks; d) Check a condition of the brake system (see the Head Nastroyki and routine maintenance); e) Check a condition of brake shoes; f) Check a condition of a pedal of a foot brake. Cleaning of the processor memory of ABS For cleaning of the processor memory turn off grounding of the plug L of the DLC socket, - the control lamp of ABS has to remain included. Make three serial grounding of the plug L within 12.5 seconds. Each subsequent grounding has to last for at least 1 second longer previous, - the control lamp has to be disconnected: a) If the control lamp after the made manipulations on grounding of the plug remains included, drive away the car on car repair shop for more detailed diagnostics and necessary recovery repair of ABS; b) If the lamp went out, make a short trip on the car, within at least 1 minute moving with a speed of 32 km/h (20 miles/h) and make sure that there was no repeated operation of a lamp. If the lamp joins again, drive away the car on car repair shop for performing diagnostics and recovery repair of ABS. Card of codes of malfunctions of ABS of models 1993 and 1994 of of the issue.
Grounding or contour of giving of food of ECU
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