Posted on Aug 13, 2008

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2002 Elantra P0121 code

Not sure what your background is, but I just posted a question.
-high idle on startup sometimes
-harsh shifts between 2-3 when cold
-only once did it not shift up from 2nd
-when on highway and driving for a while, engine surge (like overdrive kicks on and off)
-when engine is hot and driving in rush hour, tranny doesn't shift very smoothly

Any suggestions?

Marty
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ericgoregonc Feb 10, 2009

my car in park idles eaithert very high, about 3k, or sometimes will fluctuate between 1.5k and 3k. While driving idle is high, about 11 1.5k, and has trouble with harsh shifts. I had codes of a bad TPS, and a misfire in 2. So I replaced the TPS and di the plugs just in case. I reset the computer and it went back to no codes and just the flutuating park idle, and shifting was better. About ten miles into driving to see if it would work itself out, it popped the codes again and went back to high park idle and harsh shifts. Please help if you have suggestions, going crazy.
Anonymous May 11, 2010

Do you have any codes set (check engine light)?

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Anonymous

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Posted on Aug 26, 2008

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Before spending the money on a new TPS, you could use electrical contact cleaner on the connector and harness, and see whether that helps. It could be dirty/corroded terminals on the harness causing the problem. It's cheap and easy and worth a shot before laying out the cash for a new TPS.

Anonymous

Yes, I had the P0121 code TPS Range/performance A code come up. Sound like a TPS switch replacement?

Marty

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Posted on Aug 20, 2008

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Well i saw your other post. try changing the TPS and see if that corrects it because that will screw up alot of stuff for your tranny.

Anonymous

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If you are getting a range performance code, then you need to put the car in nuetral and adjust the cable on the range switch on the transmission. If you look almost under the air filter you will see the range switch and the cable being connected to it. If you notice, there are two "prongs", one on the cable bracket, the other on the range switch. Each "prong" has a hole in the end of it and they must be in alignment when the gear selector is in nuetral. Put the car into nuetral and then use a 12mm socket to loosen the nut on top of the cable bracket and adjust the two holes until you can slide a pin into them and lock them back down into place. This should stop your problem.

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