F14 code Jenn-air

its 5 years old. I just replaced the oven bake ignitor as it was black. Now I get the F.14 code. I am trying to avoid the $130 service call fee. My hunch is the sensor is bad, as it heats up to 135 degrees when I set it to 550 degrees. Exactly how do I use a volt meter to test this? Any other advice/feedback?

Thanks!
Al

C’mon you experts…

model JGR8875QDS. Age 5 y/o. The oven bake ignitor was just replaced, now the F.14 code is displayed. Jenn-Air says it is a "runaway lower oven temp." They diagnose it as a bad sensor or control board. I am trying to avoid the $130 service call fee.

Can anyone please walk me through how to use a volt meter to test a sensor?