p0872 transmission fluid pressure sensor/switch c circuit low (history) (immature)

[el es tu]

while accelerating onto the highway in 1st, I shifted to 2nd at around 4krpm and the car just kept climbing to 4500, then acted like it hit the rev limiter twice before shifting

I scanned it and got a p0872 transmission fluid pressure sensor/switch c circuit low (history) (immature)

I have had some issues with the trans shifting wonky in the past - im wondering if its a sensor or the harness... where is this located, how hard is it to replace (if I should even replace it all all???) and is it expensive?

Thanks!