Goodman furnace GDS80904BXBC , blows cold air, and high limit 4 blanks

https://hvac-boss.com/troubleshooting/goodman-furnace-error-codes/

According to this page, you can usually fix this 4 blink diagnosed problem by changing the air filter or tightening wiring (which it has a cautionary warning about tightening such too much) and checking the flue for blockage. The furnace has activated the primary open limit circuit.

Here is a troubleshooting page about the Goodman just blowing cold air: https://temperaturemaster.com/goodman-furnace-troubleshooting/#Goodman_Furnace_Blowing_Cold_Air

Poor air flow in the Goodman caused by blockages can result in the tripping of the rollover switches which would cause it to blow cold air. That is a safety measure. You don't want gas furnaces burning with insufficient air. Think carbon monoxide. Besides the air filter, the flame sensor or the burner could be dirty. The idea of trying to DYI that cleaning job is rather off putting. I hope changing the filter would work.

I trust it is not a fuse in the pilot flame sensor circuit blown. A repairman has the voltage testers for checking the electronics involved.

I can empathize with this. My furnace, another brand, went out recently. The repair man didn't know why it went out but simply adjusted a handle controlling gas flow to a position slightly different from what was recommended and it worked. All for $200.

https://www.repairclinic.com/RepairHelp/Furnace-Repair/36-377--/Goodman-Furnace-Troubleshooting

https://www.youtube.com/watch?v=zO1jKqwXu8s

https://www.goodmanmfg.com/products/gas-furnaces

Turn the power off at the breaker. Wait 10 minutes and turn it back on. That is the closes you get to a system reset, however, they say this
How do you reset a Goodman furnace?
Press and hold the red "Reset" button in the center of the rollout limit switch component. Hold the button for one to two seconds before releasing it..

This says Code 88 is a dirty filter. After the reset, pull the filter out and try again. If it runs, vacuum the filter and buy a new one next time you are passing Home Depot.

There is also an Error E8
E8 High Stage Pressure Switch Stuck Close at Start of Heating Cycle

Goodman furnace error code 88 - ROMA Heating HVAC AC LTD

https://romaheating.ca > goodman-furnace-error-code-88
Jan. 7, 2021 - Your furnace may be blowing cold air because the filter is too dirty. A dirty air filter blocks airflow over the furnace's heat exchanger, ...
Missing: gmvc950704cxab ‎' Must include: gmvc950704cxab

Diagnostic Code Identification System

https://mobile.goodmanmfg.com > faultcodes
Once all menus have been satisfied push the SUBMIT button. 5. To reset the search for a new search click the SEARCH button. © 2011 Goodman Manufacturing Company ...

Goodman GMVC950704CX Installation Instructions Manual

https://www.manualslib.com > manual > Goodman-Gm...
Goodman GMVC950704CX Manual Online: Status Codes. S TATUS C ODES INTERNAL CONTROL FAULT/NO POWER O P NORMAL OPERATION E 0 LOCKOUT DUE TO

Look on the interior panel on the furnace for the diagnostic codes.

Reset the power to see if the furnace tries to light. If it tries & fails, it is an ignition issue ie hot surface igniter, dirty flame sensor. If the LED's still are lit up, it is most likely a limit that is open.

high limit switch, no proof of flame.

4 blinks indicates a failure at the high limit switch. This switch is usually located on the heat exchanger face plate and has two wires going to it. Usually it fails because the furnace has over heated. The most common reasons are a plugged filter or coil that is limiting the airflow over the heat exchanger. Turn off the power to the furnace, replace the filter, clean any coils in the plenum and verify that all the vents in the home are open. Then turn the power back on and see if it is fixed. :)
If the above solution does not fix the problem, the limit switch itself may be bad from excessive heat. Replace it with a new one. Good Luck!

On Goodman furnaces, 4 flashes usually means open high limit. Look for any burnt or loose wires or any resettable limits, they should have a red button that clicks when you push on it and wire going in and out of it with spade clips. If the open limit is not resettable, jump it out to verify its open and if that fixes the problem, replace the defective limit. Best of luck.

Depending on the age of the furnace you may be able to adjust the cool down. On some furnaces there is a silver box usually made by honeywell. This is your fan limit control. If you take the cover off you will see a dial with different temperature settings with 3 pins in a grove. The first one is fan on with temperature rise this turns the blower on when the furnace starts and warms up. The second is the fan off after furnace shuts down, this would be the one you want to adjust to a higher temperature to keep the blower from blowing cold air. The last pin is the high limit if the furnace gets to this temperature it will shut the furnace off but keep the blower running. Make sure that the thermostat fan option is set to auto and not on.

blowing cold air on this furnace usualy caused by high limit trip, or flame roll out. the first one, (high limit) is from insf. air flow. (blocked filter,bad zone damper?
The second,(flame roll out) caused by bad heat exchanger,blocked vent.ect.

Witch blower is running, the inducer or the systems blower?
System blower could mean the the high limit is opening and shutting down the systems gas train, I would check this out first.

The other problem could be with the pressure switch for the gas train, it is supplied from the inducer motor, check to see if it is operating fully.

HSI boards do go from time to time, this sounds more like a system control problem.