P1778 means the Rogue CVT did not achieve the expected step-motor or ratio-control response. Preserve fluid temperature, primary/secondary speed, commanded ratio and companion codes; verify fluid with Nissan's temperature-based procedure and test power, grounds and valve-body control. NTB10-150a applies specifically to the 2010 S35 Rogue and directs control-valve assembly replacement plus applicable TCM reprogramming after its full procedure. Later Rogue CVTs require their own ESM and calibration strategy.
Match the symptom
Select the closest observation. The result changes the first test; it does not name a part to replace.
Save CVT data before cycling the ignition.
What can set P1778—and how to separate it
The order below is evidence-driven, not a universal probability ranking. Vehicle year, repair history, companion codes and the operating condition in freeze frame change where diagnosis should begin.
| Possible cause | Evidence that supports it | First useful test |
|---|---|---|
| Step motor or control-valve assembly fault | ESM/CONSULT diagnosis and commanded ratio response | CVT data and actuator diagnosis |
| Valve-body hydraulic/control fault | Pressure/ratio response fails with applicable code | Control-valve diagnosis |
| Harness, connector or TCM control fault | Electrical test fails | Loaded circuit test |
| Incorrect, degraded or overheated CVT fluid | Level/type/temperature history abnormal | Fluid procedure and temperature data |
| Internal belt/pulley damage | Slip, debris or inspection evidence | Nissan CVT inspection procedure |
Capture ratio-control evidence before reset
Save CVT fluid temperature, commanded and actual ratio, primary and secondary speeds, step command, pressure data and every engine/transmission code. Cycling the ignition may alter fail-safe and remove the best symptom snapshot.
Reproduce only in a controlled setting. Slow launch after highway operation can be unsafe in traffic, and severe shudder or overheat warnings require stopping.
The 2010 bulletin is a precise repair path
NTB10-150a names the 2010 Rogue S35 and the P1778/slow-acceleration condition. Its action is control-valve assembly replacement and TCM reprogramming when the service-procedure part-number check applies.
That instruction does not automatically transfer to a 2011–2020 Rogue, Rogue Sport or another CVT. Identify transmission and current TCM calibration before ordering parts.
A complete transmission is not the first assumption
Use Nissan's fluid-level and condition procedure, electrical tests and ESM step-motor diagnosis. Valve-body hydraulics, wiring and control must be separated from confirmed belt or pulley damage.
After repair, enter calibration data and perform reprogramming/initialization exactly as required. Correct ratio response under the original condition with no returning P1778 is the verification.
Save these scan-data clues
Freeze frame is a snapshot of conditions when the PCM matured the fault. It can distinguish an idle-only problem from a load, cold-start or monitor-completion problem. Clearing first throws that context away.
- Exact VIN, platform, model year and engine sales code
- All confirmed, pending and permanent companion codes
- RPM, load, coolant temperature and vehicle speed
- Relevant commanded and actual scan data
- Recent service, repairs and symptom conditions
- Manufacturer bulletin and current software/VIN status
A practical diagnostic workflow
- 01Confirm the exact CVT and code status
P1778 procedures change by platform and transmission.
- 02Preserve CONSULT data
Record temperatures, ratio commands, speeds and companion codes.
- 03Inspect fluid by Nissan procedure
Use the specified fluid, level temperature and safety method.
- 04Test power, grounds and harness
Do not condemn an internal part through a bad circuit.
- 05Run the ESM step-motor/ratio diagnosis
Compare commanded and actual behavior.
- 06Apply a bulletin only if exact
The known 2010 Altima/Rogue branch has strict boundaries.
- 07Program and initialize as instructed
Valve-body/TCM work may require calibration data and learning.
Do not replace the most commonly named component from P1778 alone. Confirm the exact engine, preserve evidence and complete the manufacturer test sequence before ordering parts.
Why the model year changes the test
Rogue diagnostics span S35, T32 and T33 generations with QR25DE, PR25DD, KR15DDT, hybrid and market-specific powertrains, while Rogue Sport is a separate model. EVAP routing, MAF strategy, catalyst layout, valve timing and CVT hardware are not interchangeable. Confirm VIN, production model, engine, drivetrain, CVT code and calibration before applying a test or bulletin.
- NTB10-150a specifically lists 2010 Rogue S35.
- S35, T32 and T33 transmissions do not share every valve body or programming step.
- Slow acceleration after extended highway driving is a bulletin-described condition.
- Rogue Sport is a different model and must not inherit Rogue CVT instructions.
P1778 FAQ
What does P1778 mean on a Nissan?+
It reports a CVT step-motor/ratio-control performance fault; it is not a generic engine code.
Can I keep driving?+
Avoid extended driving because acceleration and fail-safe behavior may become unsafe.
Does it always require a transmission?+
No. Circuit, valve-body, fluid and control faults must be tested first.
Is the step motor serviced separately?+
Service strategy depends on the exact CVT; Nissan bulletins may direct a control-valve assembly.
Can low fluid cause it?+
Incorrect level or fluid condition can affect hydraulic response, but use Nissan's temperature-based procedure.
Can clearing the code fix it?+
No. Cycling the key may leave fail-safe temporarily but does not repair the cause.
Does the 2010 bulletin apply to every Altima or Rogue?+
No. It names specific 2010 applications and requires its full procedure.
What confirms repair?+
Correct commanded/actual ratio response, required initialization and no returning P1778 under the original condition.
Ford diagnostic references
These documents explain Ford monitor operation. Exact pinpoint tests, connector views and specifications must be selected for the truck's VIN and model year in current service information.
01Nissan Bulletin NTB10-150a — 2010 QR25 Altima/Rogue P1778Applies to 2010 QR25 Altima and 2010 Rogue; directs control-valve assembly replacement and applicable TCM reprogramming after the full procedure↗02Nissan TechInfoOfficial VIN-, model-, engine- and transmission-specific Electronic Service Manual information↗03Nissan owner manuals and guidesOfficial model-year operating, warning, fuel and maintenance information↗