P1777

CVT Step Motor Circuit

Car Fault Codes Nissan Transmission

Can you still drive? With care, short trips only

Who can fix it? Needs a specialist or dealer

Typical repair time 1 hour – 6 hours

Typical cost SAR 200 to 5,000

What it means

This is a Nissan-specific code for vehicles with a CVT; the same number can mean something different on other makes. The step motor is an electric part inside the transmission that controls the ratio change between the two pulleys, and the code means the transmission control module (TCM) detected an open or short in its coil circuit. The ratio may then stay fixed, causing weak take-off or high engine speed at cruising speed.

Models covered: Nissan models with CVT, mainly around 2003–2012 (e.g. Murano, Altima, Sentra, Tiida/Versa, X-Trail).

Symptoms4

Noticeably weak take-off from a stop, as if the car is in a high ratio.
High engine speed while cruising, or the ratio not changing smoothly.
Check engine light on; a transmission light may flash on some models.
The transmission enters fail-safe mode and limits speed.

Possible causes5

A loose or corroded connector at the transmission or the TCM.
A broken or shorted wire in the harness between the TCM and the transmission.
An electrical fault in the step motor coils inside the transmission.
Damage to the internal transmission harness.
A faulty TCM (less common).

How to diagnose5

Read all codes from the TCM and ECM with a Nissan-capable scan tool.
Inspect the transmission and TCM connectors for corrosion, loose pins or oil intrusion.
Measure step motor coil resistance from the TCM connector side and compare with the manufacturer specification.
Check wiring continuity and for shorts to ground or between wires per the wiring diagram.
Check the transmission fluid level and condition before deciding on any internal repair.

How to fix6

Clean the connectors and repair damaged wiring in the external harness.
Repair the internal transmission harness if confirmed damaged.
Replace the step motor or control valve assembly, depending on what is available for the model, then fill with the CVT fluid type specified by Nissan.
Write the transmission calibration data to the TCM with a Nissan-capable tool if the model requires it after internal parts are replaced.
Replace the TCM if confirmed faulty, then program it.
Clear the codes and road test to confirm the ratio changes smoothly.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low when an external connector or wire is the cause, and rises sharply if a step motor or valve assembly with CVT fluid and calibration, or a new TCM, is needed.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Does this code mean the whole CVT is ruined?

Not necessarily. It is an electrical code, and a connector or wire may be the cause, so the circuit is tested first before opening or replacing the transmission.

Why do some repairs need a Nissan tool?

Many Nissan CVTs need calibration data written to the TCM after internal parts are replaced; without it the transmission may not work properly.

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This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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