While driving on the highway, I pressed the brake to slow down, then pressed the gas pedal to accelerate, but the car didn’t increase in speed at all. The dashboard displayed the emergency brake and battery warning lights. The engine didn’t rev. I turned the car off but couldn’t restart it. Eventually, I had to get a tow truck to jump-start the battery, and I was able to drive back home. The car passed AutoZone battery and alternator load test, but got the following codes:

P0826 - Up and Down Switch Input Circuit
P0868 - Transmission Fluid Pressure Low


I haven’t used the car since. Any ideas what might be causing the problem?

 

Question: Do you have the parking brake on? Usually the combination of the Brake and Battery light means the alternator is dead, so it's strange it passed the test. The fact that the car only started after a jump indicates a weak battery. Here's what Google says about the other codes:

A "P0868" code on a Nissan CVT indicates that the transmission fluid pressure is low, meaning the transmission is not generating enough pressure to properly shift gears, and could potentially lead to issues like slipping gears or difficulty accelerating; this is a serious issue that requires immediate attention from a mechanic.

What could cause a P0868 code on a Nissan CVT:

• Low transmission fluid level:
  The most common cause, check the fluid level and ensure it's within the proper range.

• Faulty transmission fluid pressure sensor:
  This sensor monitors the pressure and if malfunctioning, can trigger the code.
• Damaged wiring or connectors:
  Check for any damaged wires or connectors related to the transmission pressure sensor.
• Leaking transmission:
  Look for signs of transmission fluid leaks under the car.
• Faulty pressure regulator valve:
  This valve controls the transmission fluid pressure and could be malfunctioning.
• Worn transmission components:
  Internal transmission components like worn clutch plates or seals can cause low pressure.
• Contaminated transmission fluid:
  Dirty or degraded transmission fluid can affect its ability to maintain proper pressure.

What to do when you see a P0868 code:

• Do not ignore the code: Driving with a low transmission fluid pressure can cause significant damage to your transmission.

• Check the transmission fluid level: Check the fluid level on a cold engine and add fluid if necessary.
• Have your vehicle diagnosed by a mechanic: A professional can diagnose the exact cause of the low pressure using a diagnostic scanner and take appropriate repair actions.

Potential repairs depending on the cause:

• Fluid level adjustment: Add transmission fluid to the correct level.

• Replace the transmission fluid pressure sensor: If the sensor is faulty, replace it.
• Repair leaks: Fix any leaks in the transmission system.
• Replace worn transmission components: If internal components are worn, they may need to be replaced.
  

A "P0826" code on a Nissan CVT, specifically meaning "Up and Down Switch Input Circuit," indicates a problem with the electrical circuit that controls the manual shift lever's up and down functions on your car, typically found in vehicles with a "manual mode" option on their automatic transmission; this could be due to a faulty switch, damaged wiring, or a faulty connection within the circuit itself.

What it means:

• Switch malfunction:
  The most common cause is a faulty "up/down" shift switch on the gear selector, which might be damaged from wear and tear, liquid spills, or improper operation.

• Wiring issues:
  Damaged or corroded wiring connecting the switch to the transmission control module (TCM) can also trigger this code.
• Connector problems:
  Loose or corroded connectors within the circuit can disrupt signal transmission.

Potential symptoms:
Difficulty shifting gears in manual mode, Erratic shifting behavior, and "Check Engine" light illuminated.

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Basically, unless you have a fancy scan tool, you're probably best to just take this to a mechanic so they can do a proper scan of the ECU and figure out what's going on. I'm not sure how to check the fluid on a CVT, but if it has a dipstick you could check that and see if the CVT fluid is low and top it off if needed.

 

If you your still having trans issues after the proper atf leveling and topping off you will most likely be looking for a new cvt or a reman or rebuilt i have seen many of the 2010-2016 cvts fail with all warning lights on and the car can't accelerate in gear low fluid needing a new trans and i have seen a quest that needed a new MAF sensors only and it had all lights on only and also the trans didn't go anywhere

 

Both error codes suggest a problem with the transmission and a lack of fluid pressure, which likely contributed to the car malfunctioning