All Nissan cars with CVT transmissions come equipped with the stepper motor. In comparison to a conventional automatic transmission, this type of transmission has fewer working parts.
A CVT transmits power using just two pulleys with variable diameter and a high-strength belt or chain, as opposed to up to nine fixed gears.
The stepper motor is connected to the ratio control valve and arm of a CVT (continuously variable transmission). Stepper motors are commonly seen in older vehicles with CVT transmissions. On certain modern automobiles, though, it has been phased out.
The ratio control valve modifies the pulley pressure to alter the transmission ratio.
The stepper motor can expand or contract to adjust the position of the ratio control valve because the transmission control module provides it a precise sequence of signals.
Your transmission will give either a P1778 or P1777 error code to the car’s computer if it notices a problem with these ratios. This will turn on the check engine light and alert you to a transmission issue with the car.
In This Article...
amc49
The output of the pump, which can only be stopped by a pressure regulator, has nothing to do with the stepper motor. The effective gear ratio can be changed as needed by the stepper, which regulates the spread of the primary pulley halves. In essence, that is the shift control.
While the fluid level is low, the transmission will instantly slip, usually when making fast turns initially. Worn fluid still creates pressure because it is still a liquid and is not compressible.
Every OEM will have a good part number that might not appear in the standard parts catalogues since they need a way to identify everything they produce. similar to ‘racing parts’ that are used in competition but aren’t made available to the general public. The same is true of many specialized technological tools. I used to research difficult-to-find items at Ford in order for them to materialize and confuse the parts staff.
When the shops all said I required a new transmission, I’ve previously mended standard ATX transmissions using as little as a 30 cent washer. There goes my skills. By fabricating a bolt into an old-school band adjustment to replace one that wasn’t on the transmission, I was able to cure my Focus’s significant 3-4 slip, and the car continues to run well now, years later. Advised to have a new trans once more.
Nissan CAN order parts, but they’ve determined it’s more profitable to just replace them. Even on these incredibly straightforward CVT, the skills are rapidly disappearing because to the fact that they cost more to identify and solve correctly the FIRST time. Even if they didn’t want to pay for such information in the first place, the CEO would lose out financially, and we cannot allow that.
STEPER MOTOR
Nissan, Dodge, Jeep, and other automakers have Jatco CVTs. The stepper motor is being phased out of the more recent CVTs, however these CVTs will remain in use. Stepper motors are still used in the majority of CVTs found in stores today.
A ratio control arm and ratio control valve are connected to the stepper motor (figure 1). The pulley follower is connected to the other end of the ratio control arm.
The ratio control valve’s primary function is to alter the transmission’s ratio, as suggested by its name. By altering the pulleys’ pressure, it does this.
The stepper motor receives a signal from the transmission control module in a certain pattern. To keep things simple, the ratio control valve’s position can be changed by extending or retracting the stepper motor.
The stepper motor regulates the ratio, and the transmission control module is aware of this. It assigns stepper motor code P1778 when it detects a ratio problem and blames the stepper motor. The stepper motor is frequently replaced because of this code. We’ll return to this later; for now, let’s examine the operation of the stepper motor.
A threaded shaft, a threaded motor/magnet, a coil with a set of two windings, a housing, and a vent end cap make up the stepper motor (figure 2).
There are two windings, and each winding consists of two regulated power wires and a ground wire. The motor in the middle is threaded and has a magnet with a north and south pole. The ratio control arm is moved by the threaded rod, which extends or retracts as the motor turns.
Let’s see how to move the stepper motor (figure 3). The north side of the motor is drawn to the magnetized winding when the 1A wire powers the winding.
The control would then proceed to energize the 2B wire and turn off the 1A wire (figure 4). The motor now does one quarter of a clockwise revolution.
You would power wire 1B and release power on 2B to continue moving in the same direction (figure 5). The motor would rotate once counterclockwise.
Power wire 2A and turn off 1B to complete the motor’s last revolution (figure 6). The motor then rotates once more in a quarter-clockwise direction.
The process repeats in the other direction if the motor needs to move in the other direction.
This is merely a brief explanation of how stepper motors work. I hope this clarifies some stepper motor enigmas for you.
Although Jatco employs a different method to operate the stepper motor, the fundamentals remain the same. In contrast to our example of 1/4 of a turn at a time, Jatco controls the stepper motor in 1/12 of a turn every step. Jatco turns on two coils simultaneously, which helps with strength and gives the stepper motor more control.
You would need to examine all four circuits if you wanted to fully understand how the stepper motor is controlled.
Nissan Altima/Maxima CVT Transmission Step Motor Fix, P1778 (JF011E RE0F10E JATCO)
My 2008 Altima started giving me the P1778 (stepper motor) death code about six months ago. I looked everywhere, high and low, only to be informed that either I needed a new valve body or a new transmission. I chose to check into this a little bit more because I didn’t have $2500 for a new trans, let alone $800 for the valve body. the only video I could locate on YouTube was of a Nissan Armada, so I figured, what the heck. I removed the valve body, yanked out the fluid, dropped the pan, and pulled out the little b*stard that was causing me so much grief.
Now that I had the component, I headed to my neighborhood parts store, where I was informed that we don’t even carry that item. I went to the dealership and was told the same thing: I needed to buy a new transmission since the old ones were “unserviceable.” This struck me as odd because I already had the part in my possession.
Finally, I took a chance and got a stepper motor from eBay. After 20,000 miles, there is still no lock, whining, or code.
- With a piece of dental floss about a foot long, you may reattach the valve body to the gearbox while holding the spring-loaded arm against the stepper motor.
- Remove the floss once a couple bolts are in place before tightening all the way.
- Reattach the trans filter and secure it with a bolt.
- After replacing it with high-quality CVT fluid, reattach the fluid pan to the transmission. Amsoil produces excellent goods.
What does a car’s step motor do?
Modern cars frequently experience problems with stepper motors. It is a small, typically inexpensive, but problematic element. especially when the signs of its failure are misdiagnosed.
The stepper motor is in charge of controlling idle speed. It can be found in cars that have an injection supply system and petrol engines. Based on a few continuously recognized characteristics, it regulates the air flow to the engine. It stops the number of revs from dropping below the minimum.
The Electronic Control Module, or ECM, which stands for Electronic Control Module, controls how the stepper motor operates. It gives the motor pulses, or “steps,” that change the angle at which the throttle deflects. Using the crankshaft position sensor, coolant temperature sensor, and the value of the manifold absolute pressure (MAP) in the suction manifold, the ECM “sees” what data is sent to the motor. It concentrates on data on engine pressure, RPM, and temperature.
The stepper motor can also get contaminated due to residue buildup, and every component involved in the operation of the engine is liable to contamination. The only real fix for this issue is frequently to remove it, clean it, clean the throttle, and then reassemble everything. In more recent automobiles, lubricating and cleaning the motor more frequently doesn’t always produce the intended outcome. After completing these processes, it’s possible that the motor begins to run, but its range is insufficient.
Electrical components can potentially cause a stepper motor to fail. For instance, one of the drivers or a burned plug. The majority of mechanics reject such ideas since replacing these components under current circumstances results in such negligible savings without any assurance of success. Therefore, changing the motor for a new one is the most practical solution. It is because stepper motors aren’t exceptionally expensive on the aftermarket.
What makes it a stepper motor?
Power is converted by all motors. Electric motors use electricity to create movement. Electricity is converted into rotation by stepper motors. A stepper motor may be extremely precisely controlled in terms of how quickly and how far it will rotate in addition to converting electrical power into rotation.
Stepper motors get their name from the fact that each electrical pulse causes the motor to rotate one step. Stepper motors are managed by a driver, which drives the motor by sending pulses into it. The amount of pulses delivered into the driver’s driver equals the number of pulses the motor turns. The frequency of those same pulses will be used to determine how fast the motor will spin.
Stepper motors are incredibly simple to manage. The majority of drivers are searching for pulses of 5 volts, which also happens to be the voltage level of the majority of integrated circuits. You only need to use one of ORIENTAL MOTOR’s pulse generators or create a circuit to output pulses.
The capacity of stepper motors to position themselves very precisely is one of its most amazing characteristics. Later on, we’ll go into more detail about this. There are always a few minor imperfections with stepper motors. The precision of the basic stepper motors from ORIENTAL MOTOR is +- 3 arc minutes (0.05deg). But what makes stepping motors so astounding is that this inaccuracy does not compound from one step to the next. A typical stepper motor will move 1.8° +/- 0.05° during each step. The identical motor will move 1,800,000deg +/- 0.05deg after one million steps. The mistake does not compound.
Stepper motors have a quick response time and acceleration. They can accelerate quickly and have low rotor inertia. Stepper motors are therefore perfect for fast, brief movements.
Which Nissan has issues with the transmission?
Problems with Nissan CVT transmissions are frequent in a wide range of Nissan automobiles. In general, anyone who owns a Nissan car with a faulty CVT transmission may be eligible to sue Nissan for damages.
Model years included in individual class actions are specified, but as the currently specified classes’ outer limits are between 2013 and 2018, any models produced in those years may be subject to the class action. Nissan’s extended warranty, however, covers all CVT models built from 2003 to 2010.
Nissan model lines Sentra, Pathfinder, Quest, Versa, Versa Note, Altima, Rogue, Juke, Maxima, and Murano are among those that could have faulty CVT transmissions.