P1778 Nissan Code: Fix The Step Motor Malfunction!

If you’re driving a Nissan with a CVT (Continuously Variable Transmission), you might be all too familiar with the challenges that can arise. One particular problem that can occur is the triggering of the frustrating P1778 code.

The P1778 Nissan code is directly related to the step motor within the CVT and can signal a range of issues affecting its performance. This article will provide clear explanations about the code and offer effective solutions.

Let’s delve into the details of the P1778 Nissan together.

P1778 Nissan: An Overview

Let’s take a quick look at the essential details of the P1778 Nissan code!

  • Definition: Step Motor Function
  • Severity: Medium
  • DIY Skill Level: Intermediate
  • Continue To Drive?: Yes
  • Estimated Repair Cost: $30 – $200

What Does P1778 Mean In Nissan Vehicles?

The P1778 code in Nissan vehicles specifically refers to a problem in the Step Motor Function or its circuit within the CVT system. This code is commonly triggered in Nissan models such as the Altima, Murano, Rogue, Sentra, and Maxima.

The CVT system in Nissan vehicles relies on a step motor, also known as a stepper motor, to control the movement of the ratio control valve, which is responsible for regulating hydraulic pressure and selecting the appropriate gear ratio. 

The P1778 code is specifically triggered when the TCM detects that the pulley ratio is not changing properly to match values commanded by TCM, resulting from the mechanical failure of the step motor.

When the CVT step motor malfunctions, the code P1778 Nissan may be triggered.
When the CVT step motor malfunctions, the code P1778 may be triggered in Nissan vehicles.
(Image credit: nissanmurano.org)

It is worth mentioning that Nissan has taken steps to address the P1778 code issue through various recall campaigns. For instance, in 2013, there was a recall – the SB-10038184-2435 TSB, specifically for the 2010 Maxima, Murano, and V6 Altima models. 

When encountering the P1778 code, the first step is to check for any related Technical Service Bulletins (TSBs) from Nissan. These TSBs contain valuable information and recommended actions for specific vehicle models. By consulting the relevant TSB for your specific car, you can determine if your vehicle falls under a recall campaign or if there are particular actions you should take to address the P1778 code.

Read more: P1777 Nissan Code: Step Motor Circuit

Special Note Regarding P1778 Nissan Code – Transmission Reverse I/P Circuit Fault

The P1778 Nissan code can have different definitions depending on the car model. The most common definition, which this article focuses on, relates to the Step Motor Function within the CVT system. However, it’s worth noting that this code may be defined as a Transmission Reverse I/P (Input/Output) Circuit fault in certain car models. 

This fault occurs when there is a discrepancy between the number of steps for the stepping motor and the actual gear ratio. It is a functional code, rather than a circuit code, for the step motor. 

Unfortunately, this issue is often caused by a failing CVT transmission. However, there is some positive news to consider. Nissan has introduced an extended warranty for 10 years and 120,000 miles on the CVT of certain models. Consult with your nearest Nissan dealership or authorized service center for more information if you’re experiencing the Transmission Reverse I/P Circuit fault code. 

How Serious Is The Nissan P1778 Code?

The severity level of the P1778 code in Nissan vehicles can be considered medium. It does not pose an immediate safety risk or cause the vehicle to become inoperable. Therefore, it is generally safe to continue driving with this code present.

However, it is essential to address the issue as soon as possible to prevent further damage to the transmission and ensure optimal vehicle performance. Ignoring the code for an extended period may lead to transmission-related problems, such as erratic shifting or reduced fuel efficiency. 

Read more: Nissan OBD1/OBD2 Codes List

Common Symptoms Of P1778 In Nissan Vehicles

Common symptoms of the P1778 code in Nissan vehicles include:

  • Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL) illuminated
  • Transmission problems or abnormalities such as:
    • Difficulty with light acceleration
    • Unresponsive throttle when starting from a stop
    • Failure to engage into gear or move
    • Transmission stuck in safe mode

Read more: Nissan Dashboard Warning Lights List

Exploring The Causes Behind P1778 Nissan Code

The P1778 code in Nissan vehicles is often caused by:

  • Faulty step motor
  • Open or shorted step motor harness
  • Poor wiring and connection in the step motor circuit

How to Diagnose And Repair P1778 In Your Nissan

Dealing with the P1778 code can be a real headache, especially when service advisors start talking about replacing your entire transmission and the costs pile up. 

But here’s the truth: you may not need to break the bank. By taking care of your CVT fluid and addressing the step motor, you can often tackle the issue without draining your wallet. 

Dive in and explore the steps to diagnose and repair P1778 in your Nissan, saving you some hard-earned cash.

Essential Tools And Parts

Step-by-Step Procedure

Step 1: Retrieve trouble codes 

Connect an OBD-II scanner to the vehicle’s diagnostic port and retrieve any trouble codes. Check if there are any associated codes and prioritize addressing them first.

Step 2: Check the CVT fluid 

Ensure the CVT fluid level is within the recommended range when the transmission is cold. If it is too high, drain some fluid to bring it to the correct level.

Inspect the CVT fluid. If it appears worn out or there are signs of aeration or contamination, you can either perform a transmission fluid flush yourself or consider having the CVT fluid professionally flushed and replaced.

Step 3: Inspect the trans cooler

Check the transmission cooler for any signs of damage or blockage that could affect fluid flow and cooling. Repair or replace if necessary. 

Step 4: Inspect the step motor harness

Check for any damage or loose connections in the step motor harness. Repair if required.

Step 5: Test the step motor

Use a multimeter to test the step motor for proper voltage and continuity. Replace the Step Motor with a new one if necessary.

Step 6: Clear trouble codes and test drive 

Use the OBD-II scanner to clear the trouble codes. Take the vehicle for a test drive to ensure that the code does not reappear and that the transmission functions appropriately.

Note: It’s important to refer to the vehicle’s service manual for detailed instructions and specifications during the process.

Check this video – he walked you through the process of repairing the P1778 Nissan code by replacing the step motor. 

DIY Repair Level And Estimated Costs

Diagnosing the P1778 code can be done by an experienced DIYer, as it involves basic diagnostic procedures using common tools. However, replacing the step motor may require intermediate mechanical skills. It is recommended to consult the vehicle’s service manual for specific instructions.

Below is a breakdown of the main repair tasks and their estimated costs for repairing the P1778 Nissan code:

Repair TaskCost Range
Diagnostic Fee$50 – $150
Wiring repair$50 – $200 
CVT fluid replacement$50 – $200
Step motor replacement$50 – $150 (part and labor)

Please note that these are rough estimates, and costs can vary depending on factors such as the vehicle model, location, and quality of parts. If you’re unsure about the diagnosis or repair process, it’s recommended to consult with an automotive professional or mechanic to ensure an accurate diagnosis and proper repairs are performed.

Wrapping Up

In conclusion, if you encounter the P1778 code in your Nissan vehicle, it’s crucial to take action and address it promptly. Ignoring the code can lead to potential transmission issues and increased repair costs. To resolve the problem, seek assistance from a qualified professional or consult your vehicle’s service manual for proper diagnosis and repair guidance.

If you’ve had any experiences or have questions about the P1778 code or any other OBD codes, we’d be thrilled if you could share them in the comments below. 

Safe travels and happy fixing!

Reference Sources

  1. Nissan USA, Xtronic CVT (Continuously Variable Transmission).
  2. CarParts, Why the Nissan CVT Is Quite Possibly the Worst Transmission Ever Built
  3. Pickup Truck Talk, How Reliable Is the Nissan CVT?.

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