What is the oil aging sensor in the CVT, where it is located and how to reset
Variator gearboxes (CVT) have only relatively recently begun to actively appear on new cars. Even experts admit that such transmissions are optimally suited only for urban conditions and for operation without increased load.
But since the demand for urban models is rapidly growing, no one is surprised by the proposals to equip them with CVT boxes. Under certain conditions, it is very practical and convenient transmission options.
As in all boxes, oil is used here. It has a certain service life. Although in the manual of many manufacturers it is specified that the grease in the variator is poured for the whole service life. In reality, this is not quite the case. The conditions in Russia are quite harsh, which causes the oil to age faster. The aging of the oil is monitored by a so-called aging sensor or meter. There is a lot of talk about it, but not everyone fully understands what they are talking about.
What is it?
First, you need to get into the essence of the oil aging meter in the variator and understand its functional purpose.
The counter or aging sensor is a special algorithm that is required to diagnose the condition of the vehicle and determine the mode of operation of the variable speed gearbox. This algorithm writes information into the memory of the box electronics. Then the service station specialists can read it and understand whether it is necessary to change the oil in the CVT or not.
This counter is not a physical sensor. It’s just a software algorithm tied to a lot of controllers connected to the ECU.
As vehicle and transmission conditions increase in severity, the interval for changing the CVT fluid flow rate decreases.
Where is the meter located
When trying to perform diagnostic or repair work related to the variator, the motorist tries to locate this controller. He believes that the device may be out of order, or he should connect to it directly to read the information.
In reality, the meter can only conventionally be considered as a sensor. It analyzes the oil and its condition, i.e. ageing, relying on different information from the ECU. Physically, there is no way you can find this device in the box of variator or anywhere else. It just doesn’t exist.
Although they call it a sensor or counter, it’s actually a programmed algorithm.
How is the information read out?
This is a rather interesting question, which has to be answered.
There are several opinions as to how and in what units the counting is done. There are versions, according to which the calculation is made by minutes, kilometers or hours. But they are all wrong.
Oil aging is counted in conventional units.
It’s a kind of score that many people associate with kilometers, analogous to mileage. But it is not correct to say that 1 point equals 1 kilometer travelled.
The algorithm is programmed to count these points, based on the service life of the box and other additional factors. The main one is temperature.
To do this, we need to take a simple example. The car is equipped with a CVT box, and is operated in normal city conditions, no additional excessive load in the form of a trailer or bad road surface. This keeps the temperature inside the variator within normal limits, i.e. in the 85-95 degree Celsius range. Each CVT box has its own temperature standards.
If the conditions are like that, then the meter will only count 1 point or 1 conventional unit for one kilometer or 1 minute of travel.
But as soon as the temperature starts to rise, the number of points per minute or 1 km increases proportionally.
When the temperature in the variator reaches about 120 degrees Celsius, which is already far from normal, then the electronic control unit will record about 5-8 points for 1 minute. If the temperature turns out to be even higher, then the number of points will also increase.
The harsher the CVT conditions, the more points are added by the aging counter, and the sooner the time for changing the oil in the box is approaching.
Severe conditions for variator boxes include:
- driving in snow;
- trips with a trailer;
- Prolonged idling in traffic jams, etc.
All these things contribute to the temperature increase and the load on the CVT. That’s why the meter runs faster.
Some automakers prescribe in the owner’s manual the interval, at which the CVT oil is changed. It is not the mileage, but the number of points on the counter that is taken into account. Most often there are figures in the neighborhood of 50-60 thousand conventional units.
It is only wrong to think that 50,000-60,000 points is the equivalent of 50-60,000 km. The points are usually added up much faster.
Is it necessary to zero the counter
Motorists who operate cars with variator gearboxes installed on them are naturally interested in one question. It concerns whether or not resetting the counter is required.
Here the answer is unequivocal. On cars with CVTs, zeroing is a mandatory procedure. If you are serviced by an authorized dealer, the specialists will be able to zero the sensor and start a new countdown of aging. Doing the reset yourself is more difficult.
Many service manuals prescribe that you have to reset the oil aging sensor in the transmission to zero. There are 2 main reasons why this is done:
- This information gives an indication of what mode of operation the car and the variator itself is in. That is, experts and just motorists can find out if there are problems on the CVT since its last reset.
- If you reset the oil aging sensor on the variator after changing it, it makes it easier to determine the next replacement date in the future.
- On some cars, if you don’t reset the counter will trigger an error when you connect specialized diagnostic equipment.
From car owner’s point of view, this information is not really needed. But it is a good way to find out the details of a car with a variator, when buying a car on the secondary market.
Errors during connection of the diagnostic or a big number of points during a short period of exploitation allows to assume that the CVT has been exploited in very poor conditions, and that is why it may have serious problems in the nearest future. The buyer is more likely to refuse to buy such a car.
Alas, variators are still far from perfect. They are the most vulnerable and delicate gearboxes, very susceptible to stress. The delicacy of the CVT makes buyers in the aftermarket extremely careful about buying used cars with variators.
Only after making sure that the variator has not been stressed and has been operated as normal can you agree to a deal. The oil aging meter will be of no small help in this endeavor.
How the reset is performed
Currently, car manufacturers do not provide a special sequence of actions that would allow the car owner to reset the aging counter on their own without extraneous equipment, as it is done in the case of resetting the same service interval.
To reset CVT oil aging gauge, you need to connect an external adapter to the ECU.
It is optimal to do it through official service centers. Dealer service stations have specialized equipment suitable for a particular make of car.
Their analogues can be purchased via the Internet, but efficiency and operability of such adapters are under doubt. Not all of them are suitable and display the necessary information.
You can simply monitor the meter through the software installed on smartphones. The phone connects to the ECU through this software, and the display shows all the parameters.
Resetting the “oil aging meter” in Jatco variators on Nissan cars (myths and reality)
1. The marketers at Nissan are very smart. )))) Since in many countries of the world (especially in Europe) when buying a car in advance(!) Calculate the cost of vehicle operation (including all expenses for forthcoming scheduled maintenance for the next three years), Nissan decided to “remove” from maintenance cards financial expenses of vehicle owners for “changing of variator oil” altogether. That is, pay attention that the lack of recommendations from Nissan representatives to change the oil in variators NISSAN connected not with the fact that the variators are superreliable (!) and the oil in them is filled for the entire life of the car, but only with the desire to reduce the cost of routine maintenance.
As a result of this marketing move, the cost of operation of Nissan cars (a kind of “cost per kilometer”) looks more attractive than competitors, which increases the sales of new cars. As a rule, all the problems associated with untimely maintenance of variator transmission, start after the warranty period, when the manufacturer’s liability ceases to operate and then the burden of CVT Nissan repair costs falls on the owner of the car.
2. A logical question arises. And then how does Nissan itself not get “warranty replacement of the variator” on the vehicles they sell within their own warranty period? After all, everyone operates a variator differently. Someone pulls trailers, someone tows in snowdrifts, etc. In fact variator drives are much harder and transmission oil in it “wears out” faster (loses its properties quicker). You have to change it (and prolong its life), but how do you know when you have to change the oil in a variator? That’s when in the early 2000’s a genius move called “variator oil ageing counter” was invented.
Where is the “oil aging meter” in the variator?
Alas, but nowhere. The oil aging counter (sensor) is a special algorithm (in fact, a certain program), which takes into account the load on the transmission and serves to read from it the operating data needed for lubricant and consumable replacement, as well as for diagnostics. By the way, this algorithm does not take any action to increase or decrease pressure inside the variator. In simple words, it is needed only for the official dealer employee to understand in what operating modes your variator was operated. If the mode was heavy, then the liquid inside needs to be changed much more frequently.
That is, once again note that physically this sensor (as a certain part) does not really exist. Calculation is carried out by means of the car ECU and information from many sensors. That is, in simple words, since it does not physically exist, you will not find it installed in any part of the box. The information is accumulated inside the electronic control unit, written based on many parameters – such as real running time, shaft rotation, temperature, mileage, speed, etc. There is a special algorithm that works, which assigns points, by counting which you can draw a certain conclusion in the operation of this transmission.
How does the “oil aging meter” count?
The idea is very simple and ingenious at the same time. The sensor counts in some “Points” (we call them “parrots” in our professional slang) they are “conditional units” of work. Points are accumulated from the operation time (each minute – 1 point or 1 unit), but they (which is important) are corrected by the temperature inside the variator. For example, temperature:
Up to 90 degrees – 0 point From 90 to 100 – 1 point From 100 to 109 – 2 points From 110 to 119 – 4 points From 120 to 129 – 6 points From 130 to 139 – 8 points
It turns out that if you’re towing in mud or snow, heavy traffic in the summer, pulling cars and trailers behind you, sudden starts with overheating, and other violent actions, you gain – “conditional units” faster and your oil needs to be changed faster. For example, Nissan (as the manufacturer) recommends changing your variator oil at 60,000 points or u.s. Note, though, that 60,000 points (u.e.) may not always be 60,000 miles, especially in big cities with huge traffic jams. And the engineers at JATCO (which produces these variators and delivers them to the Nissan assembly line), recommend doing a partial oil change in the variator every 30,000-40000 km and a partial oil change with filter change every 60,000 km. Whom to believe more (and whether to change the oil in the variator by mileage or by points) is up to you.
How do you look at the oil aging meter (where do you see the points on your variator)?
As one option (by the way, the most common in Russia) – install on your head unit (GU) in the car or on your phone program CVTz50 (here in our blog about this program and why it is needed in general – www.drive2.ru/o/b/502024091054637980/ ).
Option number two. This data can be displayed (on the same remote control of the car or on a cell phone) in “Torque Pro” program.
Is it necessary to reset the counter?
If you are planning to change CVT fluid not by mileage, but by condition, and you want to monitor the remaining life of the CVT fluid, of course it is advisable to zero it every time you change the oil in the variator. For example, for Nissan cars in electronic service manual it is written (literally) – Delete CVT fluid deterioration date with CONSULT-III after changing CVT fluid.
Literally “Delete CVT fluid degradation date after changing CVT fluid” You can see in the same CVTZ50 program what the sensor is reset.
Does this sensor affect the CVT oil pressure?
Alas, it does not. In the Russian language internet, for some unknown reason, the common myth is that, supposedly, at a certain mileage (when the grease inside is starting to lose its properties), this sensor begins to adjust the pressure (increasing or decreasing) for better performance of the transmission as a whole. Unfortunately, this is not the case.
There is indeed a loss of viscosity of transmission oil from aging, there is even such an indicator as Suntistox (cSt), that is, speaking in Russian – “the fluidity of oil through a calibrated hole in the funnel” (cc per second). And this is not a fixed number, but always a range. These values need to be maintained throughout the entire service life (from change to change) and do not need to be readjusted. Variator manufacturers, in their turn, take into account the “degradation” of oils, and set clearances in friction pairs in advance, which work within the permissible ranges! And this, by the way, is equally true for both variator and engine. That is, you just need to change fluid at certain mileage and characteristics will be restored! And it’s not by pressure, it’s by mileage.
If you have changed the oil in the variator, but the variator is behaving strangely, what should you do?
First of all, it’s definitely not because you “reset” or “didn’t reset” this oil aging counter. It has no effect on the CVT oil pressure and therefore has no effect on normal/ abnormal transmission operation. Therefore if abnormal transmission operation begins, the first step is to measure the pressure in the CVT oil. We’ve described how to do this in detail on our blog here – Proper Variator Oil Pressure Measurement
Secondly, it is advisable not to delay and go to a CVT service center that specializes in the repair of variators and that you trust. For example here ( www.Jatco.su ) these diagnostics are free. Why is it better not to delay? Because it’s always cheaper to diagnose problems with variators at the initial (!) stages of failure than to do this when you will need to overhaul your alternator. It’s simple. If you want to save money, go in for diagnosis at the first sign of any problem. Don’t wait for it to go away.
Any questions and/or objections? Feel free to have a discussion in the comments below.
Are you having any problems with your variator? Then you’d better call us and come to us for diagnosis (we are in Moscow and St. Petersburg). Our phone in Moscow is 8 (499) 110 12 41 Our phone in St. Petersburg is 8 (812) 334 18 49.
Interesting and useful links . Our other interesting articles about variators on our blog (which will help you save money if you start having problems with your variator):