error code 1870 isn't very descriptive in the diagnostic codes:

P1870, P1873, P1879, P1885, P1886, P1888, P1890, P1891

are listed as A/T Concerns.

So this happened b4? Hum, if they can't fix it I think in 3 attempts it fails as a lemon car - if it's a new car.

So if you paid $300 then I guess it's not under warranty. so not new car then.

Car info is helpful when posting...

Let us know what happens....

Good Luck