If your 2007 – 2012 Nissan Sentra CVT has gone into failsafe mode, it’s either because of a mechanical failure or temperature issue. So let’s take a closer look and figure out what’s going on.
What Transmission Do I Have?
According to the technical service bulletin/TSB NTB12-057c, which you can read right here, the following three issues are common in the 2007 – 2012 Nissan Sentra equipped with the CVT transmission.
Fluid temperature protection logic mode, a.k.a. failsafe mode, is designed to turn on in the event that the CVT fluid temperature has exceeded a set threshold. If this happens, the Nissan CVT will remain in a preset gear ratio to prevent further damage to the transmission. This will significantly reduce vehicle performance, but it will allow you to drive home or to the nearest repair shop, in theory.
Mechanical failures can trigger failsafe mode. However, the following three situations are the most common triggers for the dreaded Nissan fluid temperature protection logic mode.
1. Too much CVT fluid
Overfilling your transmission is nearly as dangerous as running it without enough transmission fluid/CVT fluid. When there’s too much CVT fluid, parts of the transmission will not get lubricated or cooled because the excess fluid will foam. This will cause the temperature to rise and result in significant damage to the seals, as well as the hard parts (gears, pulleys etc.).
2. Not using the correct type of CVT fluid
The second most common thing to trigger failsafe mode in your Nissan Sentra CVT, is using the wrong kind of CVT fluid. Carmakers recommend using a specific CVT fluid because that chemical formula is designed to work with the various materials, tolerances and specifications of your transmission. Using the wrong kind of CVT fluid can result in serious damage to the seals, CVT belt, valve body and hard parts (gears, pulleys etc.). To avoid such chemical damage, it’s recommended that you use genuine Nissan CVT fluid NS-2, NS-3 or their equivalent.
3. Wrong coolant/water mixture
CVT fluid in your transmission is cooled by being pumped up into the radiator, where it is piped through a special chamber that releases the heat using both air and coolant in the radiator. If the concentration of ethylene glycol is more than 60%, the CVT fluid will not be cooled properly, which will trigger failsafe mode. To keep this from happening, Nissan recommends using a 50-50 mix of ethylene glycol and water.
What Transmission Do I Have?
Unfortunately, the Nissan CVT does require a bit of finesse and maintenance in order to keep it functioning properly. If any of the above three situations has happened, remember that significant internal damage can occur. You do have a very good option to keep your Sentra on the road however, and that is to invest a remanufactured Nissan CVT from Street Smart Transmission. These have been completely reengineered to address many of the common factory design flaws. And they are backed by a 3-year/unlimited mile nationwide warranty. If you would like to learn more, click here.
