AutoCodes – Generic – P1777

P1777 Code - Step Motor Circuit

Quick Answer

The Step Motor changes the step by turning 4 coils ON/OFF according to the signal from Transmission Control Module (TCM). Common causes include Faulty Step Motor, Step Motor harness is open or shorted, Step Motor poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P1777 indicates Step Motor Circuit.
Common causes: Common causes include Faulty Step Motor, Step Motor harness is open or shorted, Step Motor poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 54,983

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Sep 29, 2020

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
Comments
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Code P1777 Description

The Step Motor changes the step by turning 4 coils ON/OFF according to the signal from Transmission Control Module (TCM). As a result, the flow of line pressure to the primary pulley is changed and the pulley ratio is controlled. The Diagnostic Trouble Code (DTC) will set when the Step Motor does not respond to the TCM command.

OBDII Code P1777 - Step Motor Circuit - AutoCodes.com — P1777 Code - Step Motor Circuit

What does this mean?

What are the Possible Causes of the DTC P1777?

Faulty Step Motor
Step Motor harness is open or shorted
Step Motor poor electrical connection

How to Fix the DTC P1777?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1777 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Information for Specific Makes

P1777 Hyundai — Powertrain Control Module Output Malfunction
P1777 Infiniti — Step Motor Circuit
P1777 Jaguar — Engine Control Module - Transmission Control Module Retard Signal
P1777 Mazda — Torque Reduction Signal Malfunction
P1777 Nissan — Step Motor Circuit

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.