Transmission not shifting properly, codes PO174, PO420, PO102 and PO720

CLE11

MEMBER
2005 HYUNDAI TUCSON
2.7L
V6
4WD
AUTOMATIC
260,000 MILES

Months ago, my car began shifting weird. I got a throttle position sensor and it fixed it for a couple months. Then it started again. An output speed sensor fixed it for about a month. Now it's started again. It revs high when I take off, then shifts hard into third gear at 20-25 MPH. Then revs high the entire time I drive it. It has a SoftTronix transmission, so I tried the manual side today and noticed whole stopped that it shows I'm in second gear doesn't not go to one. Then on the highway it won't shift to four, only three, where it revs high. It shows these four codes below.
PO174
PO420
PO102
PO720

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

More than likely the P0720 is causing the hard shifting at this point.

The other codes are lean codes and most likely not related to this issue so we will need to address those separately.

Here is a guide that will help with this testing that we need to run through in order to figure this shifting issue out:

https://www.2carpros.com/articles/how-to-check-wiring

Please see the attached info below and that will walk us through the testing that we need to do.

Please let me know what questions you have.

Thanks

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