What is wrong with the shifting?

1997 Hyundai Sonata 105,000
The car shifts properly when started the first time but after a stop light it will shift erraticly and not shift into overdrive. Turn off ignition and wait a few seconds and restart car and it will shift great and go right into overdrive until you stop again. I feel it is electrical but do not know where to look next. I changed the fluid and it looked good. Does this car have a relay for the transmission or a solenoid and what is the best way to replace if so.

Do you
have the same problem?
Tuesday, December 12th, 2006 AT 11:33 AM

1 Reply

Hi Dennie,

I had similar problems on my Accent. The first thing to check are the electrical cables which plug into the transmission. I bet that there is basically no slack between them (where they plug into the transmission) and where they are tied to the side of the engine compartment. Do the electrical cables coming out of the connectors on the transmission seem to be pulled tightly to one side? If so, then you likely have erratic connections within the connectors on the tranmission. I solved this problem on my Accent as follows:

--Disconnected the negative battery cable. (Always do this when working on anything electrical on a car!)
--Removed any items in the way of allowing me easy access to these cables and their connectors on the transmission.
--Then I pulled a bit of extra slack in the electrical cables where they are tied to the side of the engine compartment. The extra slack now will prevent the connectors at the ends of the electrical cables from being tugged on too much where these connectors plug into the transmission.
--I plugged and unplugged each cable three or four times to basically allow the "scraping" action from plugging and unplugging to clean away any oxidation on the connector pins.
--Then I stuck my finger in a jar of vaseline and smeared vaseline into each connector until each connector was well packed with vaseline. The vaseline is to prevent any corrosion to the contacts inside the connectors.
--I plugged each cable's connector back into the transmission and verified that each electrical cable now had some slack to allow for engine movement, shaking, whatever.
--Reinstalled whatever was in the way that prevented easy access to the cables.
--Reconnected the negative battery cable.

The tech manual for my Accent says that the code will clear after three startups and stops (cycles) of the engine as long as the same fault isn't detected again. Yep! After three cycles the check engine light was out and hasn't come on again since.

Anyway, this is a relatively easy and no-cost check which rules out a simple issue due to some bozo on the assembly line who didn't know that you have to leave some slack in these electrical cables to prevent tugging on the connectors!

I hope this works! :D
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Saturday, December 30th, 2006 AT 6:46 PM

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