I set the oven to bake at 350. When the temp on the display says 350 I checked the internal temp of the oven with a separate oven thermometer and it reads 190. I press the Clear/Off button to turn the oven off and I immediately press Bake and set the temp to 350 and press Start. The temp reading on the oven reads 264. The temperature inside the over is still 190. The oven temp on the display starts to go up until it reaches the preset temp of 350. The actual temp inside the oven is still below 200.

Any suggestions on repairing this, it just started doing this.

Thanks,
Tim

Have you tried leaving the oven tester in the center of the oven for about an hour? If you are using the round temp testers they respond pretty slow. If it is low temp for sure there is a way to raise the temp around 30 degrees. It should be in your manual if you still have it. Otherwise if the sensor is good the only other part is the control..It looks to be no longer available. Hope this helps..

Below are parts for an oven which i think may be yours but the Model Number does not include a 0.
Please check your model number.
Parts for GE JTP15WA1WW Oven - AppliancePartsPros.com

Place the thermometer up by the oven sensor to see what the reading is in that area.

If it is close to what is shown on the control panel then perhaps the bake element is not working and it is hotter at the top of the oven where the sensor is.
On most units in pre-heat and bake they switch back and forth between the bake and broil elements to provide a more consistent temperature gradient in the oven.
Check that the element is OK.

If the temperature is also low like your previous tests then odds are that the control board is toast. Unfortunately it is obsolete.

Thanks Denman. I can't find the model # with the 0 in it on line either, but it's definitely there on the door sticker.

Well I did as you suggested, set Bake to 350 and put the thermometer next to the oven sensor. After 15 minutes the oven control panel read 350 but the thermometer next to the oven sensor read 240. I also carefully touched the bottom heating element and it had not heated at all.

So I think what's happening is the oven control is not turning on the bottom element and is getting bad data or is interpreting the data from the sensor incorrectly.

element checked ok with an ohmmeter. I think the oven control module needs to be replaced. since the module is no longer available I decided to replace the oven thanks for all your help.