The bad CVT stepper motor symptoms warn of the potential damage to your engine and vehicle. They will harm your vehicle’s performance if you don’t fix them properly.
These symptoms are common and easy to check, such as sluggish acceleration, hesitation, weird sounds, etc.
In some situations, the faulty stepper motor can stop working thoroughly and prevent your car from operating.
Thus, fixing a faulty stepper motor is necessary to maintain your vehicle’s performance.
Let’s read more about the signals of a bad CVT stepper motor that requires a replacement or repair for your Nissan to run best.
What Is A CVT Stepper Motor?
The stepper motor is a component of most Nissan models with CVT transmission.
This transmission has fewer moving parts than the conventional automatic type, including two pulleys with high-strength chains or belts.
A stepper motor in a CVT (Continuously Variable Transmission) works in harmony with a ratio control valve and arm.
The transmission control module will allow the stepper motor to contract or extend to change the position of the ratio control valve by transferring signals to it.
The transmission will send a P1777 or P 1778 error code to the vehicle’s computer if it detects transmission ratio problems.
This will illuminate the Check Engine Light to warn you of a failure with your vehicle’s transmission.
What Are Bad CVT Stepper Motor Symptoms?
When your vehicle hesitates or becomes inoperative, the main culprit is a faulty motor.
Besides, you can monitor typical signs, such as sluggish acceleration, abnormal sounds, winding damage, wrong driver, or short circuit failure.
If your stepper motor is not working properly, don’t ignore the above Nissan bad stepper motor symptoms.
The following sections describe each. Let’s take a closer look at each symptom in detail!
Hesitant Cars
The car may hesitate due to a faulty stepper motor. This is one of the uncomfortable Nissan CVT stepper motor symptoms if you are trying to move to other lanes on the road.
Besides, this problem is dangerous and annoying when driving, especially in a quick and busy traffic.
Abnormal Operation When Car Is Running
When the motor runs but does not follow pulse commands or if there is abnormal vibration or excessive noise, this can be due to the bad stepper motor.
Thus, you must give your engine an additional inspection and repair.
Sluggish Acceleration
If your car accelerates slower than normal, it’s probably the bad stepper motor to blame. It turns out to be disappointing (or even dangerous) for you over time.
Thus, you shouldn’t ignore it whenever your vehicle accelerates sluggishly.
Position Error When Car Moves
Every step the stepper motor in your Nissan takes has an error. Yet, they are not cumulative and are always below the +/-0.05° specification.
Knowing when errors occur and the exact number of errors is critical for proper troubleshooting.
So you should identify the patterns and accurately calculate the position error through the actual position compared to the target position.
Besides, the linear error must be converted from inches or mm to pulses, degrees, or steps if the Nissan stepper motor can be coupled to a ball screw.
Reverse or Drag Forward
A bad stepper motor can cause your vehicle to lurch back and forth while changing gears. This symptom may also be a noticeable indicator that poses a risk to you.
Strange Noise
An unusual noise beneath the hood may be a common and serious symptom of a failing stepper motor.
When you press the accelerator, your stepper motor may be broken if you hear grinding, whining, or other weird sounds.
Taking your car to an auto repair shop for an expert mechanic to diagnose and fix it when these symptoms appear is important.
Inoperative Stepper Motor
The stepper motor often fails with the engine running, but your vehicle is stationary. This sign informs you of the malfunction of stepper motors through its revs, but the engine does not run.
CVT owners may even face early failures under certain circumstances. Nissan has solved this failure by launching versatile hardware changes with the release of the 2013 model year.
High-pitched Squeal Audio Noise
The noise coming from the engine is a high-pitched squeal.
Noise may affect the chopping control of the Nissan stepper motor. In most cases, audio noise impacts only the control circuit due to stability issues within the circuit.
The efficient chop frequency varies from desired frequency to the subharmonic frequency. Voltage spikes and excessive electrical sound may also shift the circuit frequency of motor control.
As soon as that frequency changes, the Nissan stepper motor stops rotating or slows down.
Faulty Driver
A faulty driver is one of the Nissan stepper motor symptoms. This problem happens as the power supply can not control the peak voltage.
You should pick a suitable clamp diode for the application. In addition, you need to choose the diode that matches the stepper motor speed switch.
This part can limit the peak voltage from the power supply to the motor.
Also, note that the stepper motor clamp diodes should have similar switching characteristics to the output transistors’ switching times.
Motor Fails To Turn
A stepper motor won’t turn unless it receives sufficient current from the power supply. Besides, the motor can fail to turn when the current lacks torque to rotate the stepper motor shaft.
The desired speed setting requires consistent torque.
If the speed setting is higher than the required torque, the stepper motor can not turn, regardless of the amount of current delivered to the circuit.
Short Circuit Failure
One of the main issues with a stepper motor is motor failure. This problem occurs because the power supply draws too much current through the device.
And a short circuit failure in the wiring may leave a severe problem in the stepper motor.
If your application is prone to short circuits, you can install overload protection equipment to fix the faulty stepper motor.
Winding Damage
The most common problem encountered in your stepper motor is damaged windings.
Per the transmission experts’ advice, I replaced this component, changed the oil and filter elements. Professional mechanics sometimes have to deal with faulty stepper motor pawls.
This pawl controls the primary pulley position via the loading valve. If it is defective, the car’s transmission gets stuck in gear.
I usually notice my shifter moves, but the gear doesn’t change in this case.
It’s best to take your stepper motor to the nearest auto repair shop to receive support from professional mechanics if it gets any failures.
Why Does CVT Stepper Motor Go Bad?
Using Wrong Breadboard
If you want to connect a stepper motor to a generic stepper driver, you can use a breadboard to link the two.
Traditional breadboards are designed to allow the solid core wire of approximately 0.6mm or 24 AWG to ensure a reliable and consistent connection.
However, most of the wires from stepper motors aren’t solid cores but consist of multiple small coiled-up cables, resulting in a smaller wire size than the breadboard expects.
Thus, when checking, the slightest movement of wrong breadboard wires leads to a momentary connection loss and a damaged stepper motor.
Disconnected Stepper Motor Wires
The stepper motor cable gets disconnected while the driver is powered on. This is a common reason why your stepper motor goes bad.
In this case, do not service the faulty stepper motor, controllers, or drivers, especially motor connections, while power is still on. This precaution is mandatory for both technicians and drivers.
Shorted Winding or Motor Case Problem
The shorted stepper motor windings or the motor case also cause failure in the stepper motor.
If you identify the root cause, don’t try to fix the engine by opening the stepper motor, as this can make the motor lose magnetism and degrade its performance.
Unfavorable Environmental Factors
The unfavorable environmental factors also result in a bad step motor.
These factors can be dust, chemical vapors, welding, humidity, moisture, and metal debris that will ruin your vehicle’s stepper motor and electronic components.
Back-driven Stepper Motor
You need to know that a load can turn the stepper motor to generate a back EMF voltage in the driver. The faster the speed, the higher the voltage level.
This voltage can damage the driver if the RPM gets too higher than normal.
Running the motor in reverse while the power is on is especially dangerous for the driver. Apply a mechanical brake or stop in any application where these phenomena occur.
What Happens If A CVT Stepper Motor Goes Bad?
Do not drive your vehicle with a malfunctioning stepper motor. The faulty stepper motor will give the engine poor efficiency and low performance.
In addition, motor inefficiency can consume a lot of power. Besides, the bad stepper motor can make torque decrease quickly.
Another effect of the defective stepper motor is the missing steps that make the engine operate ineffectively.
How to Fix a Bad CVT Stepper Motor?
For those looking for an easy answer to fixing bad stepper motor symptoms, below are some options I recommend checking out.
Step 1: Remove the bad stepper motor to replace it if you own safe and supportive tools. You can do this by removing the old transmission oil from your car.
Then, drag the transmission oil pan and clean it with brake cleaner.
Step 2: Continue removing the valve body and transmission filter. Then, unbolt the 3 bolts that hold the transmission filter to the vehicle. When the bolts have got loose, take out the filter.
Step 3: Now you remove all fasteners attaching the valve body to your car and a series of bolts to remove the valve body.
Step 4: Drag the stepper motor and replace the old one with a new one. Once finished, reinstall everything in the same order.
FAQs
What Does Code P1778 Mean?
This code is a diagnostic trouble code in Nissan. It works when the ECM or PCM catches a signal that indicates a failure with the transmission step motor function.
How Much Does Nissan Stepper Motor Replacement Cost?
The Nissan Altima step motor replacement cost can range from $2,000 to $4,000. Yet, in some cases, you should try to fix and replace the faulty stepper motor yourself to save cost.
Conclusion
Feeling worried and frustrated is normal when you discover that your Nissan appears to have bad CVT stepper motor symptoms.
This makes your vehicle with CVT transmissions prone to various problems.
Thus, when identifying a faulty stepper motor as a main culprit of CVT transmission problems, replace it to fix the failure and improve your Nissan’s performance.
A bad stepper motor can cause hesitation or a jerky feeling when your vehicle accelerates or runs on the road.
In addition, it can lead to strange noises to warn you about the unusual issues inside the system.
Checking your stepper motor is essential to get the proper repair or replacement for your vehicle to work better.