Lp furnance ignites for 3seconds then shut off.

They are listed inside the front panel of the main unit.
LED CODE
EACH OF THE FOLLOWING STATUS CODES IS A TWO DIGIT NUMBER WITH THE FIRST
DIGIT DETERMINED BY THE NUMBER OF SHORT FLASHES AND THE SECOND DIGIT BY
THE NUMBER OF LONG FLASHES.
STATUS

11 NO PREVIOUS CODE - Stored status code is erased automatically after 72
hours. On RED LED boards stored status codes can also be erased when power
(115 VAC or 24 VAC) to control is interrupted.
12 BLOWER ON AFTER POWER UP (115 VAC or 24 VAC) -Blower runs for 90
seconds, if unit is powered up during a call for heat (R-W closed) or R-W opens
during blower on-delay.
13 LIMIT CIRCUIT LOCKOUT - Lockout occurs if the limit or flame rollout switch is
open longer than 3 minutes.
- Control will auto reset after three hours. - Refer to #33.
14 IGNITION LOCKOUT - Control will auto-reset after three hours. Refer to #34.
21 GAS HEATING LOCKOUT - Control will NOT auto reset.
Check for: - Mis-wired gas valve -Defective control (valve relay)
22 ABNORMAL FLAME-PROVING SIGNAL - Flame is proved while gas valve is
de-energized. Inducer will run until fault is cleared. Check for:
- Leaky gas valve - Stuck-open gas valve
23 PRESSURE SWITCH DID NOT OPEN Check for:
- Obstructed pressure tubing. - Pressure switch stuck closed.
24 SECONDARY VOLTAGE FUSE IS OPEN Check for:
- Short circuit in secondary voltage (24VAC) wiring.
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 - Restricted vent
- Disconnected or obstructed pressure tubing
- Low inlet gas pressure (if LGPS used)
If it opens during blower on-delay period, blower will come on for the selected
blower off-delay.
33 LIMIT CIRCUIT FAULT - Indicates a limit, or flame rollout is open. Blower will
run for 4 minutes or until open switch remakes whichever is longer. If open
longer than 3 minutes, code changes to lockout #13. If open less than 3 minutes
status code #33 continues to flash until blower shuts off. Flame rollout switch
requires manual reset. Check for: - Restricted vent
- Proper vent sizing - Loose blower wheel - Excessive wind
- Dirty filter or restricted duct system.
- Defective blower motor or capacitor. - Defective switch or connections.
- Inadequate combustion air supply (Flame Roll-out Switch open).
34 IGNITION PROVING FAILURE - Control will try three more times before lockout
#14 occurs. If flame signal lost during blower on-delay period, blower will come
on for the selected blower off-delay. Check for: - Control ground continuity
- Flame sensor must not be grounded
- Oxide buildup on flame sensor (clean with fine steel wool).
- Proper flame sense microamps (.5 microamps D.C. min., 4.0 - 6.0 nominal).
- Gas valve defective or gas valve turned off - Manual valve shut-off
- Defective Hot Surface Ignitor
- Low inlet gas pressure
- Inadequate flame carryover or rough ignition
- Green/Yellow wire MUST be connected to furnace sheet metal
45 CONTROL CIRCUITRY LOCKOUT Auto-reset after one hour lockout due to;
- Gas valve relay stuck open - Flame sense circuit failure
- Software check error
Reset power to clear lockout. Replace control if status code repeats.
If status code recall is needed, briefly remove then reconnect one main limit wire to display
stored status code. On RED LED boards do not remove power or blower door before initiatingstatus code recall. After one status code recall is completed component test will occur.

here is a link copy and paste

https://www.fixya.com/support/t6287232-carrier_8000ts


.

Hello, if the burners do not fire at all there could be a few reasons, the igniter could be bad, the burners could be dirty not allowing gas to flow, the pressure switch could be open. There should be a led light code on the control board that will tell you where to look. Begin by checking the hose between the inducer motor and pressure switch, it could be loose, kinked, or have a obstruction in it such as water not allowing the switch to close, also check the flue pipe for any obstructions. If the switch checks out good than the igniter should be inspected for any cracks or white spots, this is a sighn that the igniter is weak and should be replaced. If the igniter is good then clean the burners.

Error Codes
A green LED indicates system faults
Steady On: System OK
Steady OFF: Board control fault or no power applied
1 Flash: Ignition failure (control in one-hour lockout)
2 Flashes: Pressure switch fault, fails open (switch is
stuck open)
3 Flashes: Limit switch open (main or auxiliary)
4 Flashes: Pressure switch fault, fails closed (switch is
stuck closed)
A yellow LED indicates flame status
Steady on: Normal flame is sensed
Flashes: As flame weakens, frequency of LED flashes
increases
hope this is helpful.

It begins its power-on cycle normally. First the updraft blower turns on for a bit, then the HSI glows bright orange, then the gas turns on and the flames ignite fully and the big blower turns on.
About 3 seconds after the gas ignites, it shuts off. That is the gas shuts off, the blower continues for about a minute then it shuts off. This cycle will repeat a few times, then usually after the second or third time everything stays on and works normally

I am sure you have gotten this fixed by now. A 1 code is a general lockout meaning it tried to light 3 times and did not. A 2 code is for a stuck closed pressure switch. That pressure switch is normally open. If unit is off, and you remove the wires and using a multimeter, ohm across it, it should be open. If not, it needs to be replaced.

Error Codes
A green LED indicates system faults
Steady On: System OK
Steady OFF: Board control fault or no power applied
1 Flash: Ignition failure (control in one-hour lockout)
2 Flashes: Pressure switch fault, fails open (switch is
stuck open)
3 Flashes: Limit switch open (main or auxiliary)
4 Flashes: Pressure switch fault, fails closed (switch is
stuck closed)
A yellow LED indicates flame status
Steady on: Normal flame is sensed
Flashes: As flame weakens, frequency of LED flashes
increases

On a call for heat, the 24 volt thermostat sends a signal to the control module. The control module will indicate a call for heat with a light on the control either blinking or remain solid depending upon model. The inducer (exhaust) blower will purge all gasses from the furnace and pressurize a pressure switch. Once the pressure switch tells the module to continue, the electronic ignition will energize and send 120 volts to the igniter. The igniter will glow and you will be able to see it if viewed thru the small inspection port. Once the igniter gets hot enough, it sends a signal to the module opening up the gas valve (24 volts). Either a pilot will come on or the burner tube will ignite then spread the flame to all burners. Lastly a safety sensor will be looking for a certain temperature within a few seconds and the furnace will continue to operate and the room air blower will turn on in a minute or two.

What could go wrong? The unit will not run if there is no signal from the thermostat (bad thermostat or broken wire), the control module does not sense a signal from the thermostat (bad control), the inducer does not energize (bad motor), the pressure switch does not close (blocked vent piping, bad switch, plugged condensate hose), the igniter does not energize (bad control, bad igniter), the gas valve does not open or there is no gas (bad gas valve, broken wire, no gas), the pilot does not light (dirty pilot), the burner does not light (bad burner, plugged orifice, not enough combustion air), the flame does not spread to each burner (bad flame spreader, dirty flame spreader, more bad burners), the flame safety sensor does not detect flame (dirty or bad flame spreader, bad flame sensor, broken wire, bad control), or the room air blower does not energize (bad fan motor, bad control).

goodman furnance the exhaust fan starts, igniter glows hot, all burners lite up & will burn for about a minute and shuts down . I think it senses the room blower does not start so it shuts down.

1
1 FLASH
Furnace fails to operate.
• Integrated control module
diagnostic LED is
flashing ONE (1) flash.
• Furnace lockout due
to an excessive
number of ignition
“retries” (3 total)1.
• Failure to establish flame.
Cause may be no gas to
burners, front cover
pressure switch stuck open,
bad igniter or igniter
alignment, improper orifices,
or coated/oxidized or
improperly connected flame
sensor.
• Loss of flame after establishment.
Cause may be
interrupted gas supply, lazy
burner flames (improper gas
pressure or restriction in flue
and/or combustion air
piping), front cover pressure
switch opening, or improper
induced draft blower
performance.
• Locate and correct gas
interruption.
• Check front cover
pressure switch
operation (hose, wiring,
contact operation).
Correct if necessary.
• Replace or realign
igniter.
• Check flame sense
signal. Sand sensor if
coated and/or oxidized.
• Check flue piping for
blockage, proper
length, elbows, and
termination.
• Verify proper induced
draft blower performance.