Failsafe mode is designed to protect the engine and transmission from further damage in the event of a mechanical failure. So let’s take a look at why your 2007 – 2012 Nissan Altima CVT is trying to protect itself.
What Transmission Do I Have?
According to the technical service bulletin/TSB NTB12-057C, which you can read right here, this condition applies to the 2007 – 2012 Nissan Altima equipped with the CVT transmission.
According to the TSB, the Nissan CVT is designed to default to fluid temperature protection logic mode, a.k.a. fail-safe mode, should the CVT fluid temperature exceed a preset threshold. When this happens, the CVT will be limited to a preset gear ratio that will significantly reduce vehicle performance.
Nissan identified three situations that are most likely to send the CVT into failsafe mode. Of course, mechanical failures can also trigger failsafe mode. But these three scenarios are sort of the first things to check off the list before diving deeper into the transmission.
1. Overfilled CVT fluid level
Believe it or not, overfilling your transmission can actually cause serious internal damage. Too much CVT fluid can cause various parts of the transmission to not receive proper lubrication because the excess fluid is foaming, and unable to lubricate or cool the moving parts. Too much CVT fluid can also cause excessive fluid pressure, which cannot only overheat the transmission, but it can also blow out seals and damage other internal components.
2. Using the wrong type of CVT fluid
If your Nissan Altima CVT has gone into failsafe mode, it might be due to the use of the wrong type of CVT fluid. Each automaker creates a specific formula that is designed to work with the various materials, specifications and tolerances for their transmissions. The chemical components of the transmission fluid/CVT can actually damage the seals, hard parts (gears, pulleys etc.) and CVT belt if they are not designed for the Nissan CVT. So if you are using anything other than genuine Nissan CVT fluid NS-2, NS-3 or the equivalent, you could not only trigger failsafe mode. But you might also cause significant internal damage as well.
3. Incorrect coolant/water mix
If the concentration of ethylene glycol is more than 60%, the engines cooling system will not be able to adequately cool the CVT fluid. Remember, the CVT fluid gets pumped up to the radiator where it releases the heat that it has collected from all of the moving parts inside of the transmission. If the antifreeze inside of the radiator has too much ethylene glycol, or too much water for that matter, the CVT fluid will not be adequately cooled, which will result in the fluid temperature logic protection mode, a.k.a. failsafe mode. To avoid this, Nissan recommends a 50-50 mix of ethylene glycol and water.
What Transmission Do I Have?
The Nissan CVT is a rather delicate transmission, and serious damage can result from any of the above three scenarios. If it has, then you should check out a remanufactured Nissan CVT from Street Smart Transmission. These have been reengineered to address many of the factory design flaws, and they are backed by a three year/unlimited mile nationwide warranty. To learn more, click here.
