If you see a 7P1 code on your thermostat, don’t be alarmed, it’s the 1dL code error you are seeing from the up to the bottom (backwards.)

Read it from the bottom , you Should be able to see an IdL code which says that the furnace is idle, in other words it indicates that there is no connection between the thermostat and the furnace.

Either way, let’s look at the causes for the 7P1 (1dL) code in the following chart.

Possible causes for the 1dL (7P1) code on a Goodman Furnace

PS: See troubleshooting video at the bottom of this guide.

Possible Cause	Fix
Firmware flitch	Restart entire system
Tripped condensate switch	Reset condensate switch
Loose wires	Secure wired
Bad circuit control board	Replace circuit control board
Bad thermostat	Replace thermostat

As I mentioned earlier, the main cause for 1dlL error is communication breakdown between the thermostat and the furnace.

When the furnace is not registering a call for heating or cooling , a thermostat will go into idle mode.

This will then trigger the 1dl code which is mostly mistaken for the 7p1 code

Firmware glitch

Obviously you don’t want to start with the hard part when you are troubleshooting the 1dl (7p1) error code.

So the easiest and first thing you want to do is try resetting your system and see if that will reset the 1dl code.

You can reset your system by flipping the furnace switch button that is located near the furnace and looks something like a lamp switch. Turn it off for at least a minute before turning it back on.

If that doesn’t clear the 1dl code, you’ll have to take a look at the condensate float switch.

Tripped condensate switch

The second thing you want to check is your thermostat display.

If your thermostat does not use batteries and relies on the C wire, it is possible that the condensate float switch is tripped and has cut power to your thermostat.

If your air handler is equipped with the condensate float switch, it will trip when the drain pan gets full.

So you’ll have to drain the water to reset the switch and restore power to your thermostat.

And if your air handler doesn’t have a condensate float switch proceed to the next step of our troubleshooting.

Loose wires

A common cause for the Goodman furnace 1dL code is loose wiring on the circuit control board. Access the furnace control board and take a look at the furnace wiring.

Ensure all wires are securely connected specially the W wire which is one responsible for heating. Try to jumper w and R.

If the furnace kicks on, there is a thermostat wiring issue and not the furnace.

So you might have to go to the thermostat side and check the wiring there too.

If all wires look securely connected but you’re still getting the 1dl code, then you may have a bad circuit control board or thermostat.

A Bad thermostat

If jumpering the wires starts the thermostat and clears the 1dl error, then your furnace wiring is good.

But the thermostat does not start your furnace or clear the error code, then the problem is probably with your thermostat.

If this is a new thermostat try rewiring the old thermostat and see if this will solve the problem.

If your thermostat is bad and is still under warranty you can get a replacement for free, otherwise you’ll need to buy a new thermostat to fix this problem.

Bad circuit control board

We know that the control board is like the heart of the furnace. It receives instructions from the thermostat and relays the instructions to any other part f your furnace

If the furnace continues to display the 1dl code and everything else looks good including the thermostat, you may have a bad circuit control board.

This is rare but it does happen. But first, call in a local onsite tech to come and do some tests before you consider getting a new circuit control board.

Final Thoughts

In conclusion if you see a 7p1 code on your Goodman furnace circuit board, that is simply a 1dl code that is read from top-downwards as you saw in the image above.

I hope you have managed to clear the code after going through this guide. If you are still facing the same problem, I encourage you to have a tech come over and assist you.

Thanks for reading.

Goodman furnace manuals: https://www.hvacpartsshop.com/goodman-service-manuals/