Brand:GE Model Number:GDT645SYN0FS Main Symptom: Has power, will not start What happens & when: This dishwasher powers on, however it will not start. The UI board seems to be functioning properly. It will allow all of the buttons to be pressed and the LED display changes the wash time accordingly. When the start button is pressed, it plays a three note ascending tone (I believe this means the door is open?) regardless of if the door is open or not.
This led me to the door switch which on the wiring diagram that came with the unit, shows as having two open/closed switches. Both of these switches test as working properly and show as closed when the washer door is closed. The wiring to the harness also shows continuity from the door switch to the control board, as well as from the UI Panel to the control board.
When the unit is placed in error mode the LED displays 144, which I believe is an inverter error, however I don’t think this unit has an inverter. I don’t see a separate inverter control board on the diagram. The unit does register the door and open and closed when in error mode by showing steady LEDs in closed and flashing in open. The unit is able to be placed in service mode, all tests perform as the should. The service manual says there are 7 available tests in service mode, however this unit cycles from 1 through 8. 8 Does not appear to actually do anything, I just want to include that if it’s pertinent
The service LED on the control board is flashing once every three seconds or so.
I removed the pressure switch to test, but couldn’t figure out how to do so. The diaphragm inside moves when pressure is applied and the housing and switch inlet are free of debris.
Any troubleshooting ideas? I feel like I’ve tested almost everything on this washer and it’s still doing the same thing.
Error Code (if any):144
Parts or tests already tried:
Photos / video link:
Yes. Based on everything you’ve tested, I would not chase the pressure switch, pump, inverter, or door latch any further. Your testing points strongly toward the main control board.
The biggest clue is the service LED: 1 flash approximately every 3 seconds. On this GE control platform, that specifically means “dishwasher is not running a cycle; select a cycle and press Start.” In other words, the main board is powered, communicating normally enough to operate the UI, but it is never transitioning into the running state when Start is commanded. A communication failure would instead flash about once per second, and Demo Mode would give 6 flashes per 3 seconds.
Also, I need to correct my previous answer about 144. I was too quick to identify it as cycle time. Given that you’re seeing it specifically in Consumer Error Mode, I would not use 144 as the basis for this diagnosis. GE’s public error-code documentation doesn’t identify 144 as a normal customer fault code.
Why I think the main control is failing
You have essentially isolated both sides of the door circuit:
Door switches → wiring → main control: good continuity.
More importantly, Consumer Error Mode actually recognizes door open versus door closed correctly. That’s much stronger evidence than simply ohming the switches. It means the main control is receiving and interpreting the door-state input.
Then you enter Service Mode and all of the individual loads operate. That tells us the machine can fill, drain, circulate, etc., and that the main board is capable of switching those loads when commanded diagnostically.
But in normal operation:
Start pressed → three-tone response → no cycle → control LED remains 1x/3 sec.
That combination makes the control’s normal cycle/start logic the standout suspect.
There’s another useful detail: GE describes Demo Mode as allowing the customer to select cycles/options and press Start while preventing the dishwasher from actually operating. However, your board LED isn’t showing the 6-flash Demo Mode indication, so I wouldn’t call Demo Mode the primary suspect.
I would still eliminate it before ordering anything: kill power for 30 seconds, restore power, then hold Start + Heated Dry/Power Dry (or the equivalent dry-option key) for 5 seconds. That’s GE’s documented Demo Mode toggle for GDT-family machines.
One test I’d do before replacing the board
Watch the main-control service LED while you attempt a normal start.
With the door open, select Normal and press Start. Then close the door.
If everything is being recognized correctly, you’d expect the control to transition from:
1 flash / 3 sec = idle
to
3 flashes / 3 sec = running cycle.
If it stays at 1 flash / 3 sec, despite Consumer Error Mode correctly recognizing the door closure, that’s excellent evidence that the main board simply isn’t accepting/initiating the normal-cycle Start command.
I would also try the opposite sequence once: close the door first, then press Start if you can access the top controls enough to do it. GE’s normal operating instructions for this family are Start followed by closing the door within the required interval.
About Service Test #8
I wouldn’t let that throw you off. The technical literature available online covers several closely related control/platform revisions, and the exact test count/load configuration varies. The fact that 1–7 operate their expected loads and #8 appears inactive isn’t enough by itself to indicate a fault. GE confirms GDT645SYNFS was manufactured from 2019–2023, so revisions within the platform are entirely plausible.
My call at this point: main control board.
I would not replace the pressure sensor based on these symptoms. A pressure/flood-level problem doesn’t fit nearly as well with the board refusing to enter a normal cycle while simultaneously passing the individual Service Mode load tests and correctly displaying door status.
If you give me the part number printed on the main control board (WD21Xxxxxx), I can also check whether this particular machine uses a personality jumper/configuration. That could potentially explain the strange 144 / extra Test 8 behavior and is something I’d want to verify before condemning the board.
The control board part number is not in the format you specify. The only P/N I see is GE265D3440G701.
When trying the tests you recommend, it would not enter or exit display mode. The service LED continues flashing 1x/3sec when attempting to start a cycle with the door open and with the door closed.
Just to add another data point - when I reinstalled the control board the UI did not automatically come back on. It required several button presses before turning back on. The service LED continues to blink 1x/3sec though. This is able to be replicated by simply turning the power off and on.