Electronic car security systems 2

Electronic car security systems

Without keyword

Electronic car security systems 3

The principle of operation of the steering wheel position sensor is quite simple. Consider this as an example of SAS mounted on BMW cars. The sensor consists of two potentiometers located at an angle of 90 °.

The readings from these two potentiometers cover one complete turn, fig. eleven

Electronic car security systems 4

steering, all data from potentiometers are repeated after +/- 180 °. The SAS sensor understands this and accordingly calculates the steering speed. The full angle of the steering wheel position thus consists of the current potentiometer reading added to the number of full turns of the steering wheel in one direction or another. So that the exact position of the steering wheel is available at any time, there is a continuous monitoring of all movements of the steering wheel – even when the car is stationary. To achieve this, voltage is constantly applied to the angle sensor from terminal No. 30. This means that the steering wheel tracking continues even with the ignition switched off. The steering angle fixed by potentiometers remains available even after turning off the power; data on the number of steering wheel turns after a power failure is lost. In order for the steering angle sensor to understand the actual relative position of the steering wheel and the wheels of the car after the power supply is cut off, the control unit integrates software that can calculate this indicator based on the speed of the wheels of the car and the current reading of the steering angle. On some car models, it is enough to rotate the steering wheel 2-3 times to the right and left on a motionless vehicle. On others, adaptation of the SAS sensor is required. This procedure is possible both with the help of a diagnostic scanner and without it. If this procedure is not performed, the control unit cannot determine the exact relative position of the steering wheel and wheels. When the vehicle starts to move and reaches a speed of approximately 20 km / h, the corresponding DSC warning lamp will light up on the dashboard. The process of monitoring the state of the steering angle determination system starts immediately when the ignition is turned ON and if the steering speed is not known, the DSC system immediately switches to passive mode, and the corresponding DTC is written to the computer memory. On cars with a conventional single-axis drive, a situation is possible when, after the start of movement, the DSC control unit manages to calculate the correct steering angle at that moment the DSC warning lam on the dashboard will go out, and the system will begin to function normally. On all-wheel drive vehicles, the warning system works somewhat differently. DTC DTC is recorded immediately when power to the rudder position sensor (SAS) is interrupted. The system immediately switches to passive mode and when the ignition is turned on, the DSC warning lamp on the dashboard lights up, even on a stationary car.

But not only the power cut is the main cause of a malfunction in the system, additional checks of the proper state of the system are carried out periodically by the DSC control unit. The algorithm, as already mentioned above, is based on the readings of the ABS wheel speed sensors and the current values ​​of the steering wheel position sensor SAS. In the memory of the DSC system EEPROM control unit, standard values ​​are written that are compared with the current data from the sensors in real time. If the values ​​do not match, then the system naturally switches to passive mode with all the ensuing consequences. Everyone who is engaged in car repair must have met with a situation when the wheels of the car are level, and the steering wheel is shifted to one or the other side. This is a prime example of a mis-calibration of the SAS sensor. Such a situation can arise both during normal operation of the car and during repair and maintenance work with steering elements of the car, as well as during service procedures for adjusting the geometry of the wheels.

Zero Point Calibration without the diagnostic scanner on Toyota vehicles is calibrated to zero position using the following algorithm.

The car should be on a flat surface with a slope of less than 1 degree. To be motionless. On cars with an automatic transmission, the gear selector must be in the “P” position and the parking brake is activated, on cars with a manual transmission, activate the parking brake. During the procedure, do not change the position of the steering wheel or rock the car. The wheels of the vehicle must be in the forward position..

1. Turn the ignition ON, but do not start the engine.

2. Using a jumper, connect and disconnect the Ts and CG contacts more than 4 times in the DLC3 diagnostic connector for 8 seconds, Fig. 12

Electronic car security systems 5

3. Verify that the VSC indicator on the dashboard is flashing to indicate a previous calibration has been reset..

4. Turn off the ignition “OFF”.

5. Verify that the Ts and CG pins in the DLC3 diagnostic connector are disconnected..

6. Turn on the ignition ”ON”.

7. Verify that the VSC indicator on the dashboard lights up after turning the ignition on and goes out after about 15 seconds.

8. After 2 seconds after turning off the VSC indicator on the dashboard, turn off the ignition.

9. Use a jumper to connect the Ts and CG contacts to the DLC3 diagnostic connector.

10. Turn on the ignition ”ON”.

11. After turning on the ignition, make sure that the VSC indicator on the dashboard lights up for 4 seconds after turning on the ignition, and then starts to flash at intervals of 0.13 seconds.

12. Wait approximately 2 seconds while the VSC indicator on the dashboard flashes and turn off the ignition.

13. Remove the jumper from the DLC3 diagnostic connector.

14. Make a test drive by car for 5 minutes to ensure that the zero position calibration of the Steering angle sensor is successful. When you turn on the ignition and start the engine, the VSC indicator on the dashboard should light up briefly and turn off.

If during the test drive the VSC indicator on the dashboard lights up again, this means that the SAS zero calibration failed or the system has a malfunction. Try the calibration procedure again. If it also fails, check the system with a diagnostic scanner for DTCs.

Also, the category of basic sensors of electronic systems for additional safety of the car should include speed sensors WSS ABS systems installed on each wheel of the car. As the ABS system evolved, the type of sensors used changed, and if at the very beginning it was simple inductive sensors, which gradually replaced Hall sensors, which now in turn have to give way to new, more advanced MRE sensors. Our colleague Mikhail Evgenievich Kudryavtsev, the address of the article on the Internet autodata.ru/article/all/nissan_pathfinder_2007_mre_sensor/, described very well and in detail the principle of their action in his article “Nissan Pathfinder 2007 MRE sensor open circuit in the ABS harness”

I would also like to add that the waveform of the MRE sensors changes depending on the direction of the vehicle (forward / backward) and the signal is not taken from a conventional ring gear, but from a disk with magnetized fragments of different polarity.

What should significantly increase their reliability and accuracy of readings, Fig. thirteen

Electronic car security systems 6

The main sensors of electronic systems of additional safety of the car, fig. 14

Electronic car security systems 7

For service and repair, it is sometimes necessary to disable electronic safety systems. On many models, you can turn off by selecting the appropriate switch position on the dashboard located in the area, selecting the appropriate ON / OFF position. But not on all models such a switch is provided, and for example on the new Toyota camry there is a special procedure for turning the service mode on and off. In this mode, the TRC and VSC systems can be forcibly turned off either using a portable diagnostic tool or by simultaneously applying the parking brake and depressing the brake pedal. Information on changes in service mode can be found in the following maintenance recommendations..

Switch to service mode (TRC and VSC systems off).

TRC and VSC systems can be turned off in the order described below:

• Using the parking brake and brake pedal:

1. Make sure the ignition is off and the gear lever is set to ”P”.

2. Turn on the ignition (ON) and start the engine..

3. Perform steps 4 to 8 within 30 seconds after starting the engine.

4. Apply the parking brake..

5. Press the brake pedal twice and release it.

6. Turn the parking brake on and off twice by depressing the brake pedal.

7. Press and release the brake pedal twice while the parking brake is applied. Note: each of items 6 and 7 should be completed within 15 seconds..

8. Make sure that the slip warning lamp ”Slip” and the message ”CHECK VSC SYSTEM” are turned on on the multi-information display. Otherwise, repeat the procedure from step 1.

9. Electronic safety systems TRC and VSC can be returned to normal operation by turning the ignition off.

• When using a portable diagnostic tool:

1. Make sure the ignition is off and the gear lever is set to ”P”.

2. Turn on the ignition (ON) and start the engine..

3. Connect the portable diagnostic tool to the DLC3 connector and turn off the TRC and VSC systems from the corresponding service menu.

4. Electronic safety systems TRC and VSC can be returned to normal operation by turning the ignition off.

Diagnostics of electronic safety systems on the example of Toyota cars.

When an ECU detects electronic additional safety systems malfunctions in ABS systems with electronic brake force distribution (EBD), emergency brake assist, traction control (TRC) or directional stability control (VSC), the corresponding warning lamps and messages on the multi-information display indicate a faulty unit , fig. fifteen

Electronic car security systems 8

In the event of a malfunction in the ABS, EBD and emergency brake booster systems, the TRC and VSC systems are disabled. Accordingly, the main indicator lamp and the slip indicator lamp “Slip” are turned on, and the message “CHECK VSC SYSTEM” is displayed on the multi-information display.

At the same time, electronic trouble codes (DTCs) are recorded in the system memory. DTCs can be read by the number of flashes of the ABS warning lamp or by the output of codes on the multimedia information display by connecting a jumper to the Tc and CG terminals of the DLC3 connector or using a diagnostic tool.

This system provides an active diagnostic mode for sensor signals. The function is activated by connecting a jumper to the Tc and CG terminals of the DLC3 connector or using a scan tool. The ABS warning lamp and VSC warning lamp flash at intervals of 0.25 s. This monitoring function checks the deceleration sensor, yaw sensor, brake master cylinder pressure sensor and speed sensor.

An example of information output on a multi-information display, fig. 16

The system status code is displayed. The DTC is displayed.

In case of certain malfunctions, the operation of electronic additional safety systems goes into emergency mode. Here are some reasons for such a transition..

• In the event of a malfunction of the ABS system and / or the emergency brake booster, the ECU of the electronic additional safety systems blocks the inclusion of additional brake systems (ABS, emergency brake booster, TRC, VSC).

• In the event of a malfunction of the electronic brake force distribution (EBD) system, the ECU of the electronic safety systems blocks the operation of this system. Even in this case, the effective operation of the brake system is ensured, with the exception of additional brake systems (ABS with EBD, brake assist, TRC, VSC).

• In the event of a malfunction of the Traction Control System (TRC) and / or the Stability Program (VSC), the electronic control unit blocks the inclusion of these systems.

• In the event of a malfunction in the communication line between the ECU of the electronic safety systems and the steering angle sensor, the yaw and deceleration sensors or the engine ECU, the ECU of the electronic safety systems blocks the functioning of the traction control system (TRC) and the exchange rate stability (VSC) system.

• If the engine ECU registers certain DTCs (this list varies by model and year of manufacture), then it blocks the functioning of the traction control (TRC) and the electronic stability control (VSC).

Also, in certain cases, when critical DTCs are detected (from the point of view of the car manufacturer), not only the TRC and VSC electronic safety systems can be disabled, but also a forced power reduction occurs through direct control to the throttle motor directly from the engine ECU to limit the maximum engine speed. The so-called mode “LIMP MODE”.

The power limitation mode is also activated in extreme situations arising on the road and when the TRC and VSC systems are turned on. When you turn on the VSC system of directional stability, the ECU of the electronic safety systems sends a VSC enable signal to the engine ECU.

Upon receipt of this signal, the engine ECU adjusts the throttle position to change engine power, Fig. 17

Electronic car security systems 9

Well, in conclusion, very briefly about what the ABS system is with the electronic brake force distribution (EBD) system.

The ECU of the electronic safety systems calculates the speed of each wheel, the deceleration rate, and also recognizes the wheel lock based on signals from the wheel speed sensors, the vehicle’s rotation speed and the deceleration. Depending on whether the wheels slip or not, the ECU of electronic safety systems regulates the brake fluid pressure in the working cylinder of each wheel, including the check and pressure valves in one of three modes: decrease, hold and increase pressure.

The table shows a good example of an ABS system with electronic brake force distribution (EBD) in various operating modes. Fig. 18

Electronic car security systems 10

Of course, this is not complete information about the structure and functioning of the additional safety systems of the car ABS, TRC and VSC, but just a thesis overview of the main points. To learn more deeply and how to understand it is possible only through the daily practice of working with these systems in the repair and maintenance of cars.

Successful to all repairs and trouble-free maintenance of their cars.

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The three most stupid electronic assistants annoying drivers 16

The three most stupid electronic assistants annoying drivers

The three most stupid electronic assistants annoying drivers

The future has already come, and no one is surprised by the available innovative technologies that the global automotive industry offers us. Moreover, many electronic functions have ceased to be a privilege of premium products, and are offered in mass segment machines. But are these “smart” options really necessary for the Ukrainian driver and is it worth it to overpay a lot of money?

We readily believe that the design of the world’s leading engineers, the purpose of which is to facilitate and secure the lives of drivers, is dictated exclusively by good intentions. But in reality, many of the electronic assistants in modern machines do not perform their functions partially or in full and are rightly perceived as another way to squeeze money out of the buyer.

The point here is not only in the specific Ukrainian road conditions, but also in the psychology of our drivers, who in any situations, and even more so in extreme ones, are accustomed to trust only themselves. As a result, inexperienced ones shy away from any interference of electronics in the process of controlling the machine, and in experienced it causes extreme irritation.

Dead zone monitoring

During movement, the sensors record vehicles moving in parallel in the driver’s blind zone, and the system warns him about this with flashing light signals on the side mirrors. The idea in itself is competent, but only the setup of this system in the vast majority of cases is such that the dead zone is stretched to unreasonably maximum sizes.

As a result, the electronics are triggered long before the entry of the neighboring car into the blind zone of the driver, which is why the signals blink almost constantly during movement. As a result, the driver does not pay attention to them and, as a matter of habit, changes his mind, relying only on his own strength.

Markup Tracking

Sometimes a car, following in its lane, slightly changes its trajectory and runs into the marking wheels. In some models, electronics warns the driver about this with a slight vibration of the steering wheel, and in other cases, the system independently steers and returns the car to its previous motion vector.

But, firstly, on our roads there is far from always perfect marking so that its sensors can fix it. And secondly, if the driver is not able to independently control the ramp, then why would he even drive?

The three most stupid electronic assistants annoying drivers 17

Driver Fatigue Control

The most useless function for which the buyer has to pay can be considered the driver’s fatigue control assistant. Many of our compatriots who had to drive cars with this option, probably in the literal and figurative senses, wondered what kind of electronic algorithm is capable of recording human fatigue.

In fact, the signs of recognition are not the trickiest – usually this is a certain frequency and manner of driving the steering wheel during a long mileage of a one-time trip. For no reason, a symbol in the form of a cup of coffee starts flashing on the dashboard, or an inscription with a caring offer to relax. This annoys a lot of people and even offends, because common sense still suggests that no one except the person himself is able to determine whether he is tired or not.

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St. Petersburg motorists do not favor electronic CTP - Car insurance 23

St. Petersburg motorists do not favor electronic CTP – Car insurance

St. Petersburg motorists do not favor electronic CTP - Car insurance

St. Petersburg motorists do not favor electronic CTP

As of February 24, in Russia in electronic form 100 thousand contracts of compulsory motor insurance were concluded. The leader in the number of purchased electronic insurance remains the Krasnodar Territory. In the region, 17,333 electronic motor vehicle policies were sold. 9495 people purchased online insurance in the Volgograd region, 6972 in Rostov.

The northern capital took only 30th place, and Leningrad region – 58th in the list of regions in terms of the number of e-insurance policies sold. CTP via the Internet was bought only by 840 residents of St. Petersburg and 200 motorists of the Leningrad region.

Recall, on July 1, 2015, an electronic insurance system was launched in Russia. MTPL in the network at the initial stage could only be extended. This opportunity was used by no more than 200 people a day. Everything changed on October 1 – by this time the e-OSAGO sales system was finalized.

Customers have the opportunity to migrate from the insurer to the insurer. And already in October, on average, 300 new auto-citizen electronic contracts were concluded daily, in November – 800 each. In 2016, experts predict a further increase in demand for electronic auto insurance.

As before, the main buyers of e-CTP are residents of remote settlements where there are no representatives of insurance companies. Actively behaves young people and representatives of the IT sector. Legal entities do not yet have access to the e-insurance system. However, it is stated that the situation will change as of July 1 of this year..

At present, in Russia 15 insurers sell CTP online. A single “tariff corridor” has been established for all companies. But there is no need to talk about full-fledged price competition within its framework: insurance is mainly sold at maximum price tags. Rosgosstrakh PJSC (about 50% of all sold electronic auto insurance), RESO-Garantia Insurance Company and Military Insurance Company remain the leaders in sales of e-policies.

An electronic policy cannot be faked – this is called one of the main advantages of acquiring insurance online. According to the Russian Union of Auto Insurers, up to 10% of paper blanks of “auto citizens” are fake. In St. Petersburg and the Leningrad Oblast, alas, there are many points of sale of fictitious insurance. Buying a policy online minimizes the risk of running into scammers.

The downside of e-MTPL is the need to print a PDF-form of an electronic policy, to carry with you and present in case of checking on the roads. While the patrol crews of the traffic police are not equipped with the means to automatically check for insurance policies by vehicle number. However, such devices will soon appear.

According to insurers, in 29 constituent entities of the Russian Federation, the number of sold CTP insurance policies has exceeded one thousand. In the top ten regions, apart from Krasnodar, Volgograd and Rostov, there are also Stavropol, Voronezh and Nizhny Novgorod regions, the Ivanovo region, the Republic of Tatarstan and Bashkortostan.

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Some general information about the standard electronic anti-theft system of the car 25

Some general information about the standard electronic anti-theft system of the car

Some general information about the standard electronic anti-theft system of the car

Some general information about the standard electronic anti-theft system of the car

The standard immobilizer works on the principle of restricting access to the engine ECU using password access. It should not be confused with other security equipment. It is an independent system, which has nothing to do with the anti-theft device, either hardware or software, and works as a completely independent level of protection. Anti-theft system corresponds to antі-theft and a separate ECU.

There are few exceptions when a standard anti-theft is combined with an immobilizer or they somehow interact (for example, “Jaguar” or “Chrysler”). A distinctive feature of immo is its “presence” in the engine management program. Engine control with a standard immobilizer is carried out with additional commands that are performed by the microprocessor of the ECU engine. Therefore, by manipulating the wiring it is impossible to hack. The hardware system is mapped to its own control unit (ECU immobilizer) or its main circuits built into other ECU.

The word “immobilizer” itself is sometimes used not in meaning or do not fully understand its meaning. Based on the publications, one can understand that the immobilizer is a kind of “immobilizer” of a car. And the immobilizer actually “immobilizes” not the car, but the engine ECU. And of course, you should not call immobilizers any physical blocking device, since such a stretch, possibly just a publicity stunt, in any case causes confusion.

Abnormal anti-theft systems are also referred to as physical blocking devices. They block using thyristors, relays and the like electrical circuits. Electronic anti-theft systems are called alarms for a reason, their main purpose is to create psychological light and noise effects. But, for the purpose of advertising and better promotion, additional anti-theft is still called immobilizers. At the same time, sellers refer to the English-language inscription on the package – “aftermarket іmmobіlіzer”. But the meaning of these terms is different, but about the translation of the word – aftеrmarkеt – contingent, are silent.

But the effectiveness of additional security systems autumn is small. Devices of the “artеrmarket іmmobіlіzer” class are their subspecies, and differ from ordinary alarms only in the presence of an increased number of physical interlocks and the absence of lights and sirens. “Аrthermarket іmmobіlіzer” operates on the basis of the same disconnectors, which facilitates theft of the car, since the disconnector can be replaced with “your” motor harness.
Back to the language. In domestic publications, the distinctive term “immobilizer” often means “immobilizer”. This word was due to inconsistencies in the meanings of the words “immobilizer” and “immobіlіzer”. In fact, an immobilizer is an immobіlіzer in Russian.

So, the immobilizer is an access restriction system that is capable of blocking the operation of the ECU at the program level. No lock – and no immobilizer.
ECU immobilizer ring antenna.
We emphasize that silencing (lack of starting) does not occur due to blocking of control circuits. This happens only in the anti-theft, which are installed on the car during its operation. By software, a standard immobilizer blocks precisely the functions of the ECU engine at the microprocessor level. ECU again asks for the password after turning the ignition off and on again.

This technology has no equal among all autonomous anti-theft systems. On the one hand, there are no chains, because with their help you can start the engine. And on the other hand, the active region of radio pulses of exchange with a chip key does not exceed a few centimeters. This means that the pulses are difficult to intercept with a radio receiver, which is able to reproduce them further (code grabber). But the radio packages of standard anti-theft trinkets and additional alarms can be considered if there is a portable antenna for the scanning receiver and a fresh trinket battery at a distance of up to one hundred meters, or even closer.

Do not confuse radio receiving scanners that sort through the receiving frequencies with radio transmitters that sort through code combinations to select a password at a given frequency. Transmitting scanners are used independently, like code grabbers, unlike receiving grabbers..
There is a misconception about the high cost of radio interception equipment. Broadband receiving scanners are really quite expensive and rare. Therefore, code grabbers have long been invented to build on the basis of affordable and cheap pagers. It should be noted that pagers belong to the range of narrow decimeter radio frequencies, and they cannot be applied to the immobilizer, which operates at long-wave frequencies.
The earliest (until 1998) immobilizer models had a separate ECU manager. Later, the chains corresponding to it functionally became more often integrated in other ECUs, and sometimes, in parts, simultaneously in several ECUs and in different places of the car.

New generation immobilizers combine the principles of active transponder and remote action devices. This combination gives the immobilizer the flexibility of remote access means, which allows you to modify the access password each time the ignition is turned on, and a new password is generated automatically.

The novelty of such devices is keyless access, when the car opens when the owner approaches. When the driver is seated, the transponder is recognized, and the engine can be started with a simple click of a button. In the distant 1999, it was believed that in 5 years this technology would be applied not only in executive cars, but also in business and economy class. But after 5 years of distribution in low-cost cars, this technology never received.

Every year, the amount of information that is read and written to chip keys is increasing. Now, not only fixed data and ordinary service supplements of the exchange protocol are read, but also information about confirmation of transponder identification. The memory area of ​​the chip key also occupies the encryption key. The algorithm is getting complicated, and this area will also grow. Now the memory of the transponder may contain an indication that the key belongs to a car of a certain brand. The reality of our days is also the fixation in the key of car mileage (“BMW”). Etc.

The car owner does not need to take any action to turn the immobilizer off and on, and this is its convenience. This happens by itself when inserting / removing the key and turning on / off the ignition. Some car owners do not even suspect that their car is equipped with an immobilizer.

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Honda automatic transmission (MRPA) - electronic control system 31

Honda automatic transmission (MRPA) – electronic control system

Without keyword

We continue the story about the automatic transmission MRPA. The first part of the article talked about the mechanical structure of this box. This part of the article will focus on the electronic control of the gearbox..

The automatic transmission electronic control system includes: an electronic control unit, sensors and solenoid valves. Gear changes and torque converter lock-out are carried out at the command of the control unit. The control unit receives signals (information about the state of the elements) from sensors, switches and other control devices. The unit processes the received information and, in accordance with the program, provides control signals to the actuators of the engine control system and automatic transmission. Automatic transmission actuators are solenoid valves for gear shifting, pressure control and torque converter lock-up.

Honda automatic transmission (MRPA) - electronic control system 32

Signals of the electronic automatic transmission control system.

Honda automatic transmission (MRPA) - electronic control system 33

An arrangement of elements of an automatic transmission control system. 1 – engine control unit and automatic transmission, 2 – diagnostic connector, 3 – selector lever lock solenoid valve, 4 – manual shift mode sensor, 5 – safety block-
carriers in the cabin, 6 – fuse No. 9, 7 – fuse No. 10, 8 – fuse No. 5,
9 – pressure sensor of the working fluid in the clutch circuit 2, 10 – speed sensor of the output shaft of the gearbox, 11 – speed sensor of the input shaft of the gearbox, 12 – e / m pressure control valve “A”, 13 – start inhibit switch, 14 – pressure sensor of the working fluid in the clutch circuit 3, 15 – e / m gear shift valve “C”,
16 – e / m gearshift valve “E”, 17 – e / m gearshift valve “B”, 18 – e / m gearshift valve “A”, 19 – automatic transmission fluid temperature sensor, 20 – e / m valve “D” gear changes, 21 – e / m pressure control valves “B” and “C”.

Gear shift control

The electronic control unit constantly monitors the state of the automatic transmission elements and determines which gear should be engaged, then sends control signals to the solenoid valves “A”, “B”, “C”, “D” or “E” of the gear shift.

The gearshift logic control system is designed to control gearshifts at selector positions “D” or “D3”. The electronic control unit compares the real conditions of movement (based on the signals of the sensors) with the states recorded in the memory of the unit and, depending on the situation, sends control signals for making up or down switching.

When shifting gears, the electronic control unit switches on or off (OFF) certain solenoid valves (A, B, C, D or E). The combination of on and off valves is shown in the table “Solenoid valve operation when shifting gears”.

Table. Shifting solenoid valves.

Selector position Gear engaged Solenoid Valve Status
A IN FROM D E
D, D3, M Switching from position “N” Off On On Off Off
First gear engaged On On On Off Off
Shift between first and second gear Off On On Off Off
Second gear included Off On Off On Off
Shift between second and third gear Off On On On Off
Third gear engaged Off Off On Off Off
D, M Shift between third and fourth gear Off Off Off Off Off
Fourth gear engaged On Off Off Off Off
Shift between fourth and fifth gear On Off Off On Off
Fifth gear On Off On On Off
R Switching from position “P” or “N” Off On Off Off On
Reverse gear engaged On On Off Off On
Reversing Prohibition Control On On Off Off Off
P Parking Mode Enabled Off On Off Off On
N Neutral gear engaged Off On On Off Off

Gear Shift Logic

Upshift Management

When the car is moving uphill on a winding road with the selector position “D”, the electronic control unit increases the range of permissible speeds for the gear selected. This is to prevent frequent gear changes (between the second and third or between the third and fourth, as well as between the fourth and fifth). Thus, the car can move smoothly. The gearshift program recorded in the control unit automatically engages the most suitable gear and sets the appropriate speed deviation.

Downshift Control

While the vehicle is moving downhill with the selector position “D”, the electronic control unit increases the speed value for upshift to increase the range of permissible speeds for the selected gear. Such control, combined with engine braking, gives the most smooth movement. There are three shift modes on the downhill and their corresponding speed range. When driving downhill in fourth gear and depressing the brake pedal, the gear changes to the lowest permissible gear. Acceleration will shift to higher gear.

Honda automatic transmission (MRPA) - electronic control system 34

Upshift Management.

Honda automatic transmission (MRPA) - electronic control system 35

Downshift Control.

Pressure management

The electronic control unit controls the solenoid valves A, B and C. When shifting gears, the pressure is controlled by solenoid valves (A, B and C) to ensure smooth engagement (disengagement) of the couplings.

The electronic control unit monitors the state of the elements (by sensor signals), processes the received data and issues control signals to the solenoid valves A, B and C.

Torque Converter Lockout Control

The shift solenoid valve “E” controls the hydraulic valve responsible for turning the torque converter lockout on / off. The electronic control unit controls the torque converter lockout by means of the shift solenoid valve “E” and the pressure control solenoid valve “A”. When the shift solenoid valve “E” is turned on, the torque converter lock-up starts. To control the degree of blocking, using the pressure control solenoid valve “A”, the pressure of the working fluid supplied to the hydraulic lock-on valve is adjusted.

The torque converter lock is engaged in second, third, fourth and fifth gears in the “D” range, in second and third gears in the “D3” band, and also in third, fourth and fifth gears in the “M” band.

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    Automatic transmission does not shift gears – causes of malfunction and troubleshooting

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