DTC Code P1778B – Step Motor Function Failure in CVT Transmission – Symptoms, Causes & Fixes

DTC Code P1778B indicates a problem in the CVT’s step motor, responsible for controlling the pulley ratio. Learn symptoms, causes, and best solutions from NayaPurana.

What is DTC Code P1778B?

P1778B refers to a Step Motor Function Failure in CVT transmissions. The step motor adjusts the primary pulley position to optimize gear ratios. When it fails, the transmission may not shift correctly or enter limp mode.

Common Symptoms of P1778B Error Code:

• Transmission stuck in a single gear (Limp Mode)

• Jerky or hesitant acceleration

• Check Engine Light (CEL) ON

• Poor fuel efficiency

• Delayed or failed gear shifts

Main Causes of P1778B Code:

1. Faulty CVT Step Motor

2. Wiring harness issues (open or shorted circuit)

3. Contaminated transmission fluid

4. Failed CVT Control Module (TCM)

5. Connector corrosion or damage

How to Diagnose & Fix DTC P1778B:

Step 1 – Diagnostic Scan

Use an OBD-II scanner to confirm the code and retrieve freeze frame data.

Step 2 – Visual Inspection

Check for loose wiring or damaged connectors near the CVT step motor.

Step 3 – Check Step Motor

Test resistance of the step motor. If out of spec, it likely needs replacement.

Step 4 – Transmission Fluid Check

Dirty or old CVT fluid can cause step motor malfunctions. Drain and replace if needed.

Step 5 – Replace Faulty Components

If the step motor or TCM is faulty, replace them with new or used parts from NayaPuranaOnline.com at competitive rates.

Why Buy CVT Step Motor or Transmission Parts from NayaPurana?

• 100% Genuine Used & New Parts

• Tested & Verified for Quality

• Affordable Pricing

• Fitment Guarantee by Experts

• Nationwide delivery across India

Internal Links to Explore More:

• CVT Transmission Parts – New & Used

• Engine & Sensor DTC Code Guides

• Buy Step Motors for Nissan/Mitsubishi CVTs

Conclusion:

The P1778B error code should not be ignored as it directly affects your vehicle's drivability and safety. Early diagnosis and repair using reliable parts from NayaPurana can save you time and money. Whether you're opting for brand-new or well-tested used spares, NayaPurana is your one-stop platform for quality car parts.