Low or degraded automatic transmission fluid (ATF); Faulty transmission speed sensor (input or output); Sticking or failed shift solenoid; Valve body wear or contamination; Damaged wiring or corroded connector at the transmission; Internal transmission mechanical wear (clutches, bands); Faulty transmission control module (TCM) or its power/ground

DTC codes / Nissan codes / P1739

P1739 · NissanAutomatic Transmission System Malfunction

Q: What does code P1739 mean?

Automatic Transmission System Malfunction. P1739 is a manufacturer-specific code stored by the transmission control module (TCM) on Nissan vehicles when it detects a general malfunction within the automatic transmission system. The TCM monitors inputs from speed sensors, shift solenoids, and the valve body, and sets this code when the overall system behavior falls outside expected parameters without pointing to one specific component.

P1739 is a manufacturer-specific code stored by the transmission control module (TCM) on Nissan vehicles when it detects a general malfunction within the automatic transmission system. The TCM monitors inputs from speed sensors, shift solenoids, and the valve body, and sets this code when the overall system behavior falls outside expected parameters without pointing to one specific component.

SystemPowertrain

Code typeNissan specific

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

Illuminated check engine light or transmission warning light, often with no other symptoms
Harsh or delayed gear shifts, especially when cold
Transmission stuck in a single gear or limp mode
Slipping during acceleration or failure to engage a gear
Unusual noise or vibration from the transmission area
Poor fuel economy or elevated engine rpm at highway speed

Common causes, most likely first

Low or degraded automatic transmission fluid (ATF)
Faulty transmission speed sensor (input or output)
Sticking or failed shift solenoid
Valve body wear or contamination
Damaged wiring or corroded connector at the transmission
Internal transmission mechanical wear (clutches, bands)
Faulty transmission control module (TCM) or its power/ground

How to diagnose and fix it

Check ATF level and condition; top up or replace fluid if dark or burnt
Scan all modules for stored and pending codes, and record freeze-frame data
Inspect transmission wiring harness and connectors for damage or corrosion
Test transmission speed sensors with a multimeter or oscilloscope
Perform solenoid resistance and functional tests per Nissan service data
Check valve body for sticking valves or debris; clean or replace as needed
If internal mechanical damage is suspected, perform a line pressure test and consult a transmission specialist

What P1739 really tells you about your Nissan

P1739 is a general code, so it rarely identifies the exact failed part; technicians must use live data and pinpoint tests to avoid replacing good components.
A low battery or poor ground can cause the TCM to set this code intermittently, so always verify charging system health before condemning the transmission.
Nissan CVT transmissions often store P1739 when the belt or pulley system is worn, but the code can also appear after a simple fluid change if the wrong fluid is used.
The code may be accompanied by other transmission codes that are more specific; always address those first, as P1739 often clears once the underlying fault is fixed.
Driving with P1739 in limp mode can cause the transmission to stay in a high gear, leading to overheating and further damage if ignored.

Can I keep driving with P1739?

It is safe to drive short distances to a repair shop, but avoid heavy acceleration, towing, or highway speeds until the fault is diagnosed. If the transmission is in limp mode or slipping severely, stop driving to prevent internal damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.