Bryant plus 90i. A 355 mav I believe. Will not ignite. I get code 34 then code 14. I have read the codes and have tried cleaning the flame sensor, blowing out all the condenser tubes and the green wire ground wire is connected to the chasis. I have taken the flame box cover off and it still didn't work so I lit it. It worked until it shut down and had to reignite itself and couldn't. What should I try next

Go to this thread and follow the directions.

https://www.askmehelpdesk.com/heating-air-conditioning/bryant-355mav-error-34-14-ignition-lockout-414840.html

Observe the operating sequence from start-up. If you don't see the glow of the hot surface ignitor, either the ignitor has failed (most likely) or the circuit board is failing to power the ignitor (least likely).

Thank you all this site was amazing in helping figure out the problem. I never opened a furnace until yesterday and I now sit in a heated home and the best part is it only cost me $27.00. The cost of a new ignitor. I was quoted from $350-$500 to fix this problem and all it took was a few hours, some helpful reading on this site and 27 bucks plus I now know a he'll of a lot about my furnace lol. Thanks again everyone

Glad you got it running

I have the same problem but very randomly. Happens once a week or so, and is, most of the times, around 6am. The furnace is blowing cold air and displaying the code 34. I turn the power off, and on again: starts no problem... every time. It is happening for the last 5 years. I replaced the flame sensor, and I believe I replace the gas igniter (not sure).
The problem has not stopped. Any ideas?

Post exact model #. When this problem occurs inconsistently, it can be tricky to pinpoint.

The model number is 355MAV060100ADKA Manufacture 8/1998. I know, it never repeats when I reset it.

If the ignitor gasket is leaking, or the main burners are dirty, the problem you are experiencing may result.

I will start replacing the ignitor and gasket. I'll let you know. Thank you for your help.