The automatic transmission goes into emergency mode. How to remove the automatic transmission emergency mode. Visual inspection and soldering of contacts

Old automatic transmissions were very reliable mechanisms. Initially, they did not have any complex electronics and control systems. The gears were simply shifted alternately, depending on the readings of a pair of sensors, there was no control system, sports modes, and so on. But according to modern trends to improve fuel efficiency and vehicle efficiency, more and more changes have been made to them. Since the end of the 80s, automatic transmissions were gradually transferred to electronic control, and in the mid-90s, electronic control units (in fact, computers) began to be installed on them, an economy mode, sports and a mode for winter appeared, the steps became more and more.

The complication and fine tuning of systems made modern automatic transmissions very reliable.

In the 2000s, automatic transmissions came to a modern form - they began to work in tandem with the engine, controlled by one or two electronic control units, the control itself was transferred to the hydraulic block of the box. The complication and fine tuning of systems made modern automatic transmissions much less reliable.

Like any computer, the electronic control unit can make a mistake, "glitch". In this case, the emergency mode will disappear after stopping and starting the engine. In some cases, it helps to reset the terminal from the battery. It is not always possible to remove the error in this way. If this did not happen, then it’s time to go for diagnostics.

In emergency mode, the car loses its dynamics, the gear does not turn on, slowly picks up speed, the control lamps are on, indicating that something is wrong with the automatic transmission.

You cannot drive in emergency mode - it exists only to drive several kilometers to the service. Usually, in an automatic transmission in emergency mode, only the third speed is turned on, at which starting from a place and driving takes place. It is not recommended to accelerate over 60 in this gear, the engine and gearbox will be very hot. Getting under way in third gear is also difficult, especially in winter.

When the "HOLD" lamp blinks, the automatic transmission goes into Emergency Mode

If the activation of the emergency mode is accompanied by the appearance of any non-passing extraneous noise from the box, it is better to use a tow truck. Serious car services that repair automatic transmissions provide a tow truck free of charge.

If a breakdown occurs on the highway, where it is problematic to find a car service, then you can take a chance and try to drive in an emergency box. Only here the result of this may be different - from "it did not get any worse" to the purchase of a new automatic transmission. You should ride, without accelerating more than 80 km / h, smoothly accelerating and braking, trying once again not to sink the gas pedal to the floor.

Reasons for leaving the box in emergency mode

Modern automatic transmissions are complex mechanisms. Unlike their predecessors, modern copies are closely connected to the engine, controlled by electronics and have a lot of sensors and protections.

The first and most common reason for the transition of the box to the emergency mode of the automatic transmission is an abnormal oil level. It occurs due to a leak in the automatic transmission, oil overflow or abnormal operation of the valve body. If we are not talking about the valve body, it is easy to fix. Leaks in the automatic transmission can be both mild and serious - for example, damage to the automatic transmission case or the gasket between the engine and the automatic transmission is out of order.

Emergency mode occurs due to a leak in the automatic transmission

Such repairs will not be cheap. In mild cases, some gasket or seal is usually responsible for the oil leak.

Low oil level in the box is very dangerous. Some gearbox assemblies cease to be lubricated normally and begin to wear out, contaminating the entire automatic transmission with their fragments. Other units begin to overheat and this also does not affect them in the best way. As a result, a chain reaction occurs - the weakest and most distant parts break, then all the rest. High oil levels are also dangerous. At best, excess oil will be thrown out through the breather. At worst, it will foam and simply lose its properties, bringing the automatic transmission to the same picture as with oil starvation.

This can also include the operation of the automatic transmission on "non-native" oil. Some automatic transmissions are so optimized and tuned that they simply cannot operate on oil with slightly different characteristics.

The second reason is that the self-diagnosis system has identified problems with the hydraulic or mechanical part of the automatic transmission. Most often it is the wear of the clutches. The electronic diagnostic system will be able to correctly indicate a breakdown only in some cases. In any case, you will need to remove the box and inspect its insides for wear and damage.

One of the reasons for the emergency mode of the automatic transmission is problems with the hydraulic part.

Worn out clutches will quickly make the oil burn, it will saturate the rest of the clutches, and at one point the automatic transmission will "stop" completely until it is pumped out. Broken gear teeth or frayed metal parts will quickly disable neighboring ones, and where it was necessary to change one small part, the entire gear will have to be changed.

The third reason is a malfunction of the electronic control unit, wiring or sensors. And this is the real scourge of modern automatic transmissions. Most often it is a bad contact of one of the loops. Most of the contacts in automatic transmissions are very small and thin wires, tracks less than a millimeter thick and loops thinner than a sheet of paper. Damaging such wiring is as easy as shelling pears. Such a small nuisance, in addition to the emergency mode, can give not frail symptoms in the form of kicks, jerks, slippage and loss of gears. The transition to emergency mode in this case is chaotic. The automatic transmission can safely drive for a week, and on weekends it goes into emergency mode on every bump.

A worse option is worn valve body channels. Dirty oil will eventually foul the channels of the hydraulic plate, wedging the plungers. Or some oil seal starts to leak.

Dirty oil contaminates the channels of the hydraulic plate

The result is one - the valve body goes crazy and opens the valves to the fullest, starting to drive a huge amount of oil through itself. Oil filled with metal debris takes on properties similar to sandpaper. The aluminum channels of the hydraulic plate wear out very quickly, and very soon the hydraulic block suffers damage incompatible with further life. The abnormal pressure that he begins to apply to the box is also not good for her. A chain reaction begins, which ultimately leads to expensive repairs.

If the transition to the emergency mode of the automatic transmission is carried out only to cold or hot, the problem may be in the temperature sensor.

When you turn on the forward gear, the box goes into an accident due to the failure of the input or output shaft rotation sensors.

If the box does not come out of emergency mode at all, the electronic control unit is most likely covered.

The most disgusting thing about such breakdowns is the enormous complexity of diagnosis. The car's self-diagnosis system may not show the cause at all. And local experts will shrug their shoulders, offering to change one or the other. And the reason for everything will be a small torn wire in the very depth of the valve body.

If the box does not come out of emergency mode, then the electronic control unit is covered

What to do if the box goes into emergency mode?

The first thing to do is to "reset" the error. To do this, stop the car, turn it off, wait a few seconds and start again. Next, you need to drive a few kilometers in a quiet mode and see if the error repeats itself.

The second thing to do is look at the oil level and condition. The level measurement procedure may differ depending on the vehicle model.

And finally, the third - if the automatic transmission emergency mode has not stopped - you must immediately go to the diagnostics in a normal service.

Audi A6 and C7

On Audi A6 and C7 cars, the most common reason for the automatic transmission to go into emergency mode is the failure of the solenoids and poor contacts. This is due to the new design of the Audi A6 and C7 automatic transmission, in which the electronic control unit is combined with a hydraulic plate. The electronic control unit of the Audi A6 and C7 constantly overheats, which does not have a particularly good effect on its work and resource. The solenoids in the Audi A6 and C7 automatic transmissions last about 6-8 years and then they must be changed.

The electronic control unit of the Audi A6 is constantly overheating

But if the automatic transmission of the Audi A6 and C7 has not skated so much yet, the reason is in the sensor or contacts. You cannot do without diagnostics of the Audi A6 and C7. Riding with an emergency automatic transmission on the Audi A6 and C7 is not a good idea, the boxes are not cheap.

BMW E90

The "wrong" oil can "get things done" in the BMW E90. Symptoms may include the transition of the automatic transmission BMW E90 to emergency mode, the activation of the engine cooling fan, jerking when driving, locking the selector after switching to position P, clicks when switching to N or P.

Surprisingly, counterfeit or deliberately inappropriate oil is to blame for everything. After flushing the BMW E90 automatic transmission and changing the oil to the original car, it will work as it should.

Volkswagen Vento

A Vento car can behave very strangely due to poor contact. The Vento automatic transmission will switch gears at 4000 rpm (in sport or economy mode, no difference). Vento's quarter speed will be activated at speeds over 100 km / h, and will immediately reset to low when braking. The temperature sensor can also cause the Vento automatic transmission to fail.

The temperature sensor can become the cause of the emergency mode of the Volkswagen Vento automatic transmission

ZF 4hp16

A simple and even miniature automatic transmission for small front-wheel drive vehicles. Automatic transmission ZF 4hp16 under repair is quite rare and almost eternal. If the ZF 4hp16 went into an accident - almost one hundred percent of its solenoids have survived. Sometimes the ZF 4hp16 comes across burnt clutches and a gear shift sensor. In emergency mode, it is worth looking at the ZF 4hp16 oil and remembering how long it has changed with the filter.

AL4

On cars of the Renault-Peugeot-Citroen concern with this "wonderful" box, a lot of interesting things can happen. The automatic transmission goes into error, and then the sport and snow modes light up at the same time. Snowflake and sport are bad signs for this automatic transmission and they usually signal pressure problems. And these are most likely dead solenoids or a valve body worn out by dirty oil.

Illumination of the automatic transmission emergency mode lamp on the instrument panel is a common problem for many car owners. It indicates critical unit malfunctions, due to which the box may need to be repaired. In this case, the car moves only in third gear.

Why does the automatic transmission emergency mode appear?

This can happen due to the following reasons:

Lack or excess of oil in the box is automatic, which affects the operation of the computer, which is why the light comes on. If there is an excess of fluid, it just needs to be removed, and the deficiency may indicate the presence of oil leaks that should be eliminated.
Faults in the hydraulic or mechanical components of the box. Emergency mode can be activated due to physical damage to the unit, for example, wear of the clutches. In this case, the sump is removed, the condition of the oil is assessed. Based on the condition of the oil, a decision is made to remove and disassemble the automatic transmission.
Breakdown of electronic or hydraulic systems. They occupy the lion's share of all cases of emergency mode occurrence. They should be considered separately. At a minimum, diagnostic equipment must be connected.

Electrical malfunctions and automatic transmission emergency mode

Among the frequent problems with the electronic control system, which leads to an emergency mode, the following are distinguished:

Damage to the temperature sensor. Because of it, the emergency mode glows constantly or after the transition to the operating temperature.
Damage to the wiring and block connection chips. The mode is constantly on or appears without much consistency. The problem is eliminated by a long inspection of the wiring and all the chips.
Breakdowns of various sensors: ABS, camshaft, air flow. Emergency mode is on permanently or from time to time, but not when changing gears. Computer diagnostics determine the cause.
Defective output or input shaft rotation sensors. The problem makes itself felt when switching to "D" with a simultaneous thud. You can fix it after diagnosing and replacing the device.
Defective control unit. It takes place if the emergency mode is permanently enabled and does not disappear. Computer diagnostics do not always determine the problem, so they resort to a trial replacement of the unit.

Remember that an automatic transmission is a complex unit, the same problems in the operation of which may indicate different breakdowns. Only experienced craftsmen with special equipment can determine them.

The transition of the gearbox to emergency mode occurs when serious failures occur to protect the power plant from damage and signal the car owner about the need to visit a service station. At the same time, the car refuses to pick up speed, the gears are not switched when the "D" mode is selected. On the dashboard, the Check AT, HOLD, Check Engine, O / D OFF indicators light up. The fault may disappear after restarting the engine. Emergency operation allows you to deliver the car to the place of repair on its own, without resorting to the services of a tow truck.

The "HOLD" indicator lights up

Abnormal transmission oil level

For normal operation of the gearbox, there is a certain range of the required amount of transmission fluid. An abnormal oil level that can cause an automatic transmission emergency mode may be:

overflow when the transmission is above the recommended level;
underfilling, which occurs when the amount of oil in the box decreases below normal.

Excess fluid in the automatic transmission leads to foaming. Rubbing surfaces are less lubricated and scuffs form at the points of contact. Increased wear of transmission parts occurs. Excess oil can be discharged through the breather. The malfunction is eliminated by draining excess oil. After that, it is necessary to reset the error recorded in the memory of the electronic control unit.

There are several reasons why there is not enough transmission fluid in the box:

Not enough oil was added during maintenance. Diagnosed by level check. To eliminate the malfunction, it is enough just to top up to the norm. In this case, it is important to use a similar transmission. Otherwise, a chemical reaction may occur between the automatic transmission additives, which will entail a significant deterioration in properties;
The automatic transmission case has mechanical damage. What to do in this case depends on the extent of the damage. If you continue to add oil, then the box will go into emergency mode at regular intervals. To detect a malfunction, an oil leak similar to the one shown below should be detected. Elimination of a breakdown can be equal to the cost of a new automatic transmission;
Failure of the gasket between the engine and the box. It is diagnosed at the place of leakage. Elimination requires replacement of the gasket. It is not so easy to do this, since it may require a complete dismantling of the power plant with related units. It is possible to shoot separately the machine only on some cars. It is recommended to visit the service station, where the craftsmen will make repairs using special equipment;
Does not hold the seal. Repair can be done independently by replacing the failed element.

With oil starvation, accelerated wear of the contacting surfaces occurs. Detached debris contaminates the transmission and increases the severity of damage. The automatic transmission overheats and creates an additional load on the engine. Prolonged driving with low oil levels can result in costly repairs.

Hydraulic malfunction or physical damage to the automatic transmission

During self-diagnostics, the electronic control unit can detect a malfunction in the mechanical part of the automatic transmission, as a result of which it goes into emergency mode. Friction clutch wear is the most common reason why the gearbox switches to abnormal mode. Electronic diagnostics do not always work correctly and rarely show an exact breakdown. It is necessary to disassemble the automatic transmission and visually inspect every detail.

Broken gear teeth or pieces of friction clutches increase the wear of associated automatic transmission components. Prolonged driving in a car in which the box has switched to emergency mode leads to costly overhauls, therefore, before the car owner has removed and inspected the automatic transmission parts, operating the car is not recommended.

Failure of electronics

The culprit for problems with the electronic component of the gearbox can be:

sensors;
connecting loops;
contact sockets.

The contacts of the sensors can oxidize or come off, and this becomes the reason why the automatic transmission has gone into emergency mode. The wiring used has a small cross-section and is prone to fray and break off. As a result, information ceases to flow to the ECU.

To diagnose the culprit of the automatic transmission in emergency mode, you need to read the error using a special scanner. Self-diagnosis is not always able to indicate a faulty sensor, therefore it is recommended to visually inspect in what condition all the available circuit elements are. If it is impossible to determine the breakdown, it is recommended to alternately change the meters and check whether the emergency mode is turned on or not.

Abrasion of the valve body channels

The box in which the oil has not been changed in a timely manner has contamination of the hydraulic plate channels. The machine works with seized plungers. Through the channels, the transmission is supplied with increased pressure. Small debris in the liquid will damage the aluminum channels. In this case, the box can work in emergency mode.

In order for the problem with contamination not to arise unexpectedly, it is required to monitor the condition of the transmission fluid. The machine only requires high quality oil. Modern machinery has become highly susceptible to improper maintenance. Measures must be taken before the automatic transmission goes into emergency mode.

Regardless of the reasons why the automatic transmission switched to emergency mode, it is imperative to visit a service center or fix the breakdown yourself. If there is a suspicious rattle, it is necessary to turn on the emergency gang and call a tow truck, despite the fact that the machine allows you to move on. In this case, the continuation of operation becomes dangerous for the entire power plant, as it causes accelerated wear of its components. It is important to remember that the breakdown does not go away on its own.

If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.

Automatic transmission emergency mode is when only one (second or third) gear works, which is a signal of a malfunction or a failure in the transmission. One gear remains working so that the car owner can get to the parking lot or car service. A breakdown is signaled by an emergency "check" icon (Check Engine) on the instrument panel.

Automatic transmission of cars.

Valve body channels wear

The work on shifting gears in the automatic transmission is carried out with the help of ATF circulating under the pressure generated by the pump. Its distribution to the mechanical units of the box takes place in the valve body using a system of solenoid valves, through special channels to create high pressure.

Like any working fluid, ATF loses its properties over time, becoming contaminated with wear products - metal dust and microchips. The chemical structure of the liquid and its color change, and a characteristic odor appears.

If the ATF is not replaced in time, the microparticles floating in it, working as an abrasive, leave scratches and scuffs on the surface of the valve body channels. The diameter of the channels affects the pressure, and any change in their inner surface leads to disturbances in the movement of fluid inside the valve body. This leads to a violation of the operation algorithm of the electronic control unit (automatic transmission ECU), which controls the distribution of flows.

Valve body malfunction is determined by some signs:

If the oil in the automatic transmission is not changed on time, unpleasant consequences can happen.

the appearance of grinding sounds when changing gear;
jerks and blows when moving the selector knob;
jerks at idle;
the engine may stall when the selector is shifted to driving mode.

Repair of the box unit consists in removing, cleaning and purging the channels. On different brands and models, the repair has its own characteristics, in some cases it is required to dismantle the automatic transmission.

In order to gain access to the valve body, drain the transmission fluid and remove the pan. After that, the electrical connectors are disconnected, the valve body is unscrewed and dismantled, which consists of several metal plates connected by bolts. It should be disassembled carefully, without losing the technological springs.

During operation, dirt and friction products are deposited on the channel walls. You can clean them with gasoline, but it is better to use liquid to clean the carburetors. The cleaned plates are carefully examined. With severe wear of parts, the entire unit must be replaced.

All procedures should be carried out in a clean room: during assembly, dust and small debris should not get inside. In the repaired box, the oil filter is changed, and fresh ATF is poured inside.

Changing the transmission oil level

This is another common reason why the automatic transmission goes into emergency mode. Even if the quality of ATF is maintained, an excess or insufficient amount of it negatively affects the operation of the transmission. When overflowing, the liquid foams, which changes its density and initial properties (cooling and lubricating), pressure drops. When underfilling, the necessary pressure is also lost, and the liquid is more quickly contaminated with wear products and overheating.

To bring the transmission fluid level back to normal, it is necessary to drain the excess or, conversely, top up. In this case, only ATF of the brand that is already filled in the box should be used. With a complete oil change, it is necessary to remove the automatic transmission pan to remove all residues.

When changing the oil in the automatic transmission, remove the sump to remove all residues.

If for several days the liquid level is stable at one mark, this indicates that there is no leak in the circulation system. If the level drops, you must carefully inspect all joints and gaskets for the presence of greasy streaks. In suspicious places, tighten the clamps, replace the gaskets or seal the connection.

Malfunctions of mechanics and electronic control system

Failure to comply with the timing of replacing the transmission fluid leads to mechanical damage to the automatic transmission. At low pressure, the friction of the clutches on the disc is maximum, the surface structure is disturbed, they "burn", and the gaps increase. This causes the box to kick. Car owners should pay attention to any oddities and changes in the car's behavior:

the car does not go forward, while the reverse gear is maintained;
no reverse;
the movement of the car in "neutral";
kickdown does not work;
"Kicks" when switching gears while driving, increased vibration;
the engine stalls or troit when driving mode is turned on.

Normal wear and tear combined with untimely maintenance can lead to mechanical failures:

jamming of valve body valves;
wear of friction discs and brake bands;
destruction or wear of the cuffs in the pistons of the friction disc packs;
wear of the splines in the clutch drum housing;
wear of the splines in the hub of the torque converter turbine and slipping of the gearbox shaft;
wear of the splines on the stator shaft of the torque converter;
deformation or destruction of blades on the reactor or turbine wheel of the torque converter.

Hydromechanical gearbox.

The mechanical part of the transmission is controlled by a programmable ECU by transmitting signals through the loops of wires. Failure of the unit itself is possible due to the effects of an aggressive environment, since over time the tightness of the protective casing of the electronic board can be violated. The readings are taken by sensors, which sometimes fail.

Signal transmission can also be interrupted due to corrosion in the connector strips or if there is a break (or corrosion inside the insulation) of the electrical wiring, the integrity of which can be checked using a tester, having at hand the electrical or wiring diagram of the car. Having found an open circuit, they solder the ends of the open circuit and insulate the junction well so that moisture and dirt do not get on the metal of the wire.

Oxidized connector pins must be thoroughly cleaned to remove accumulated dirt and corrosion. Pay attention to the condition of the insulating gaskets. If it is not possible to replace them, a silicone sealant should be used.

What to do if the automatic transmission goes into emergency mode

Influence on vehicle movement

When the emergency mode is turned on, only one high-speed gear remains operational. The car does not lose speed, and many people have a question whether it is possible to drive in such a situation. Using a car will make the problem worse.

When the box goes into emergency mode, you must slowly, at a speed of no more than 40 km / h, get to the service or to the parking lot if you plan to carry out diagnostics yourself. For this, the manufacturers have provided for the possibility of working in emergency mode of one gear.

You need to start the check by determining the error code - cars with electronic control and monitoring systems have a self-test function. By connecting the autoscanner to the dedicated connector of the electronic unit, you can display the required readings on the display.

The scan result and the table of error codes will tell you in which direction to search further. The fault lies either in the electrical part and control, or in the mechanical or in the solenoid valve system. Next, you need to decide whether to continue the diagnosis yourself.

When the malfunction is detected and eliminated, it is necessary to reset the error in the ECU memory, otherwise, during normal operation of the transmission units, the “check” on the panel will mislead the driver.

Let's start with the fact that today there are several types of automatic transmissions:, and. At the same time, for each type of gearbox, various malfunctions are characteristic, and quite often and regardless of the type of gearbox, the automatic machine "rises" into emergency mode.

In this article we will look at the classic automatic transmission with (hydromechanical automatic transmission), what is the emergency mode for an automatic machine of this type, and also why the automatic transmission goes into an "accident".

Read in this article

Automatic transmission emergency mode: what is it

So, the transition of the gearbox to emergency mode occurs if there is a breakdown or malfunction of the unit. In other words, turning on the emergency mode on the machine signals the occurrence of certain malfunctions.

At the same time, notifications or warning lamps check AT, HOLD, check engine, etc. light up on the instrument panel. If the automatic transmission "got" into an accident, the car stops dynamically accelerating, the sharp response to pressing the gas pedal disappears, the gears are not switched in D mode, etc. The fact is that in this mode the car starts off and moves only in third gear.

At the same time, the emergency mode itself can be considered protective, since its inclusion allows you to prevent a number of more serious damage to the automatic transmission. Even the emergency mode of the automatic transmission retains the ability to continue driving on its own to the nearest service station.

In other words, you cannot constantly drive in the automatic transmission emergency mode, but you can get to the car service without either a tow truck. Now let's look at why and when the automatic transmission emergency mode turns on, the reasons for its activation, as well as options and ways to solve the problem.

Automatic transmission gets into emergency mode: reasons

Let's start with the fact that modern automatic transmissions are quite a complex unit. At the same time, as practice shows, there are several main reasons why the automatic transmission "falls" in an accident.

First of all, a low or high level of ATF in the box can lead to malfunctions, as a result of which the emergency mode is activated by the command of the automatic transmission ECU.

A decrease in level can occur as a result of leaks, while an excess occurs often due to errors during maintenance of the box. For example, overflowing fluid in an automatic transmission leads to foaming, and a lack of oil leads to starvation.

The result is a decrease in pressure and deterioration of lubrication, rubbing surfaces at the points of contact wear out heavily. The electronics fixes deviations from the norm, the emergency mode is turned on, an error is recorded in the ECU by the box.

For this reason, if the box goes into emergency mode, it is necessary. It is also recommended to carry out a self-diagnosis of the automatic transmission (with such an opportunity and the presence of skills to carry out this operation).

Another cause can be malfunctions associated with the operation of hydraulic devices, as well as problems with the mechanics. For example, the automatic transmission emergency mode can turn on if the automatic transmission case is damaged, slipping, worn out, skidding or "burned", there are problems with the gas turbine engine, etc.

In this case, it is necessary to carry out an in-depth diagnosis of the automatic transmission. The check begins with computer diagnostics, but such a scan does not always allow you to get a clear idea of the nature and cause of the malfunction.

In this case, it may be necessary to dismantle the gearbox pallet in order to inspect for the presence of dirt, friction dust, metal shavings. In some cases, for troubleshooting, it will also be necessary to completely remove the automatic transmission and disassemble the unit in order to assess the degree of wear and the condition of individual elements.

The third reason for the transition of the machine to emergency mode is problems with the electronic control system of the automatic transmission. In this case, the symptoms can be different, the malfunction can be "floating" or persist permanently.

For example, it works fine on a cold box, but after warming up, the automatic transmission immediately goes into emergency mode. In such a situation, the culprit is often the temperature sensor, which requires replacement.

If the gearbox "falls" into emergency mode unexpectedly, that is, regardless of various factors and conditions, then the cause may be trivial damage to the electrical wiring, problems with contacts, etc. In this case, an experienced diagnostician checks the wiring and connections.

We also add that if the gearbox unexpectedly goes into emergency mode, and such a transition does not occur during gear changes, then the reason may be sensors (camshaft sensor, etc.). In this case, you need a comprehensive one.

Also, often problems with the automatic transmission arise when the driver moves the selector to position D or at the time of switching from 1st to 2nd gear. At this time, a blow is heard in the box, then the automatic transmission emergency mode is activated. In this situation, there is a high probability of damage to the shaft rotation sensors.

It should be remembered that the contacts of the sensors can oxidize or break off, thin wiring often breaks, loops wear out, etc. As a result, the connection with is lost. This is also one of the answers to the question of why the automatic transmission went into emergency mode.

To diagnose automatic transmission in emergency mode, it is better to read errors using a diagnostic scanner, since automatic transmission self-diagnosis is not always able to identify a problem. If the diagnostics give no results, then the breakdown should be looked for manually (by checking the sensors, "ringing" the circuits, etc.).

If the automatic transmission is in emergency mode all the time, while restarting the engine or resetting errors does not help, and the sensors and wiring are in order, then the possibility of problems with the transmission ECU should not be ruled out. In this case, they often resort to the method of replacing the block with a known worker for verification purposes.

A common cause of automatic transmission failure is contamination / damage to the channels, the appearance of scoring in the valve plate, and malfunctioning of the solenoids. In this case, the machine operates in emergency mode. The reason is the increased sensitivity to the quality of the oil in the automatic transmission and the pressure of the fluid.

To avoid such a breakdown, it is necessary in a timely manner. You also need to use only such ATF fluid that the manufacturer allows for use in a particular type of automatic transmission.

Remember, mixing transmission fluids from different manufacturers can lead to the additive packages reacting, as a result, the properties of the oil will change and the automatic transmission will malfunction.

It turns out that if the automatic transmission has switched to emergency mode, the oil level is normal, but its color, smell, viscosity and general condition are in doubt, then you should diagnose the box and be prepared, at least,

What is the bottom line

As you can see, there are a lot of reasons why the automatic gearbox emergency mode is turned on. At the same time, even rare activations of this mode, which are eliminated by restarting the internal combustion engine, indicate that the problem with the machine already exists and with a high degree of probability will only progress.

As for the errors and failures themselves, prolonged driving in a car in which the box went into emergency mode is not allowed. In other words, in this mode, you can only get to the car service, while avoiding the load on the automatic transmission.

Let us remind you once again that until the breakdown or malfunction is eliminated, the normal operation of a car with an automatic gearbox in emergency mode is prohibited! Moreover, if the automatic transmission has already "gone" into an accident, but when driving, extraneous sounds are heard during the operation of the machine (grinding, hum, crunching, bumps), then it is better to refuse to drive to the service on its own.

The optimal rhenium in such a situation would be to call a tow truck, since towing a car with a faulty automatic machine without hanging the driving wheels can lead to even more serious consequences for the automatic transmission, which is already faulty by itself and went into the "accident" mode.