Hi I am having an issue with a Carrier furnace model #58STA90. It will not light and it gives a code of three short flashing led lights and then one long. I checked the igniter and did not see any cracks across it.

31 PRESSURE SWITCH DID NOT CLOSE OR REOPENED - If open longer than five minutes,
inducer shuts off for 15 minutes before retry. Check for: - Excessive wind
- Proper vent sizing - Defective inducer motor
- Low inducer voltage (115VAC) - Defective pressure switch
- Inadequate combustion air supply - Disconnected or obstructed pressure tubing
- Low inlet gas pressure (if LGPS used) - Restricted vent

If it opens during blower on-delay period, blower will come on for the selected blower off delay

See your manual on the link below. Page 44 figure 50.

http://www.docs.hvacpartners.com/idc.../58st-18si.pdf