RPM gauge Does not work

[hitordie]

Hello Everyone. new to site so forgive me. Have an 04 Sonat 4cyl with 141,000 miles. RPM Gauge doesn't work most of the time and check engine light is on. Went to Oriles and they said the code was p0320....

from time to time the gauge will work but only for a few hours and the check engine light remains on. about a week ago the light went off and the RPM gauge worked for 3 days.

Also noticed that the car seems to not be shifting right all the time. when going up a steep hill it doesn't always downshift unless i either give it more (alot more) gas or manually shift it with the shifter. Also some times when Cruise control is set it seems to get stuck when it should shift up.

Car runs good though other than that. was just gonna trade it in but decided against it. What is the problem and what do i need to do to fix it?

Thanks for all the info!

[Norubit]

This one may be simple and only cost you less than $100. More than likely your crankshaft sensor has completely failed or fails once it heats up. The ECM takes the readings from the crankshaft and camshaft position sensors and uses that to determine when to fire the injectors, spark the plugs and shift the transmission.

You should be able to replace this yourself fairly easily. I had one fail on my old car when it got warmed up the car would not restart until it cooled down. Eventually, it completely failed.

If the problem is because of a wiring fault that can be quite a bit more difficult to track down. I'd start by testing the sensor or just replacing it.

Check this link for more details
2004 Hyundai Sonata P0320 Diag Err Cd (Ignition Failure Sens

Personally, I prefer to replace defective sensors with OEM parts
MISFIRE SENSOR for 2002 HYUNDAI SONATA|27370-38000