The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2018 Sentra SV - CVT acting up, P0740 code

0

Mike T. · rep 0 · May 25, 1:52 AM · 1 replies · solved · Question

Vehicle: 2018 Nissan Sentra SV

My 2018 Nissan Sentra SV with the CVT transmission has been acting really strange lately. It feels like it's slipping sometimes, especially when accelerating from a stop, and the RPMs will flare up without much speed gain. Yesterday, the Check Engine Light came on, and I got a P0740 code: "Torque Converter Clutch Circuit Malfunction".

I know Nissan CVTs have a reputation, but I'm hoping it's not a complete transmission replacement. Is there anything common that causes this P0740 code on Sentras?

What steps should I take to diagnose this? I'm worried about driving it too much with this issue.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 1:52 AM

0

ClearTheCode admin answer:

The P0740 code on your 2018 Nissan Sentra, indicating a "Torque Converter Clutch Circuit Malfunction," is a common and concerning issue often associated with Nissan's Continuously Variable Transmissions (CVTs). The symptoms you describe—slipping and RPM flare—are classic signs of TCC engagement problems.

Common Causes for P0740 on Nissan CVTs:

  1. Low or Contaminated CVT Fluid: Incorrect fluid level or degraded fluid can significantly impact CVT and TCC operation. Nissan CVTs are very sensitive to fluid condition.
  2. Faulty Torque Converter Clutch (TCC) Solenoid: This solenoid controls the engagement and disengagement of the torque converter clutch. If it's sticking or failing, the TCC won't lock up properly.
  3. Valve Body Issues: The valve body contains solenoids and fluid passages that control transmission operation. Issues here, particularly with TCC control valves, can trigger this code.
  4. Internal Torque Converter Failure: The torque converter itself might be failing, preventing the clutch from engaging or holding properly. This is often a more severe and costly repair.
  5. Wiring or Electrical Issues: Damaged wiring or poor connections to the TCC solenoid or transmission control module (TCM) can also cause this code.

Diagnostic Steps You Can Take:

  1. Check CVT Fluid Level and Condition: This is crucial. Check the fluid level according to your owner's manual (often with the engine warm and running). Note the fluid's color and smell. Burnt-smelling or dark fluid is a bad sign.
  2. Scan for Other Codes: Sometimes, other transmission-related codes might be present that provide more context.
  3. Monitor TCC Slip: If you have an advanced OBD-II scanner, you can monitor live data for TCC slip. Excessive slip indicates a problem with TCC engagement.

When to See a Shop: Given the nature of CVT issues, especially with a P0740 code and noticeable driving symptoms, it's highly recommended to have your Sentra inspected by a qualified transmission specialist or Nissan dealership as soon as possible. Driving with a slipping torque converter can cause further damage to the transmission, potentially leading to a complete failure. A professional can accurately diagnose whether it's a solenoid issue, valve body problem, or internal torque converter failure, and advise on the most cost-effective solution.

Menu

Help & account