Why does the X-Trail suddenly fail to upshift?
2 Answers
When the car cannot upshift, the automatic transmission remains in 1st gear during driving and cannot shift into 2nd gear or higher gears. Alternatively, the automatic transmission may shift into 2nd gear but cannot shift into 3rd gear or overdrive. Governor malfunction: Unstable RPM (gasoline vehicles), uneven fuel supply from individual pumps - readjust fuel supply quantities for each pump. Clean, grind, or replace injector nozzles with carbon deposits or dripping issues. If rated RPM cannot be reached, replace permanently deformed governor springs. Gear position switch failure: Vehicle fails to start - default startup positions are P or N gear. If gear position switch is faulty or gears are misaligned, the vehicle won't start. Severe driving jerks may occur as faulty gear position switches might input abnormal shift signals, affecting driving comfort.
That day, while driving my X-Trail, I suddenly noticed the gear wouldn't shift up, and my heart skipped a beat. There could be several reasons, with the most common being transmission fluid issues—insufficient fluid pressure or dirty fluid clogging the passages, preventing the shifting mechanism from moving. Faulty sensors like the vehicle speed sensor or throttle position sensor can also cause the computer to misjudge the shift timing. Solenoid valve failure is another common issue, especially in older cars that have been driven for a long time, as they're prone to sticking. If it's just one specific gear that won't shift up, it might be due to clutch wear, requiring an inspection of internal transmission components. I suggest trying some DIY steps first: switch to manual mode while driving to see if you can force a shift to a higher gear; then check the transmission fluid level and color—if it's dirty or low, replace it immediately. If that doesn't work, don't force it—pull over and find a professional shop to read the fault codes. Don't worry, most of these issues can be fixed with minor repairs.
