Control and program problems with your dishwasher can be caused by a number of things. In this article, we're going to help you diagnose and fix the issue by taking you through some checks to perform.
If your dishwasher has completely lost power, is stopping and starting, is displaying fault codes or doesn't seem to be working on the correct program, you're in the right place! Read on to get to the bottom of the issue and get your dishwasher back up and running again!
How to diagnose control and program problems with a dishwasher step by step
For help with diagnosing control and program problems with a dishwasher, watch our how-to video or follow the step by step guide below.
You'll need:
Safety First!
Before you begin this repair, be sure to switch off your appliance and completely disconnect it from the mains.
Problem: Dishwasher not turning on
The first thing we're going to look at is if your dishwasher is completely dead and will not switch on.
Check 1: Socket power
Unplug the dishwasher and plug in something else in its place, such as a hairdryer, to ensure there is power coming from the socket it is plugged into.
Check 2: Plug
If the power in the socket is fine, next you'll want to check the plug and make sure that the fuse in the plug hasn't blown. To check this, take the back off of the plug with a screwdriver.
Then, get a multimeter and set it to the lowest resistance reading. Check the resistance on the leads of your multimeter by shorting them together. The reading should be around 1.7 ohms.
Then, place the probes onto either end of the plug fuse. Your reading should be similar to that of the probes if the fuse hasn't blown. If the reading is different, the fuse has blown and will need to be replaced.
Check 3: Control board
If you have established that the fuse in the plug is fine, the next thing to do is check the continuity between the plug and the control board in the dishwasher. In the dishwasher that we are showing below, the control board is located at the top on the inside of the door. The location can vary from model to model and can be at the bottom or on the side of your dishwasher so be sure to check your user manual.
When you have found the location, start by removing the screws around the control panel to access it.
Here you can see the control board. You will need to test for the continuity between the control board and the plug. To do this, you'll need to check how the power comes down through the live pin (bottom left) and neutral pin (bottom right) on the plug. The power will then possibly pass through an on/off switch if your dishwasher model has one. If it does, make sure the switch is turned on for this. It then goes from the switch to the control board. How you can test for this is to look for a short circuit on the meter. Normally a short circuit is a bad thing but in this case, it shows that there is a connection between the plug and the board.
Start by placing one of the probes of the meter onto the live pin of the plug.
Place the other probe of the meter and place it onto the brown pin on the control panel.
Because you're looking for a short circuit, the multimeter should read only 1 or 2 ohms or less.
This will indicate that the power is getting from the plug to the control board but not any further and the dishwasher is dead because the control board is faulty. If, when you do this, you aren't getting a reading on the meter, try moving the probe on the board around all the different wires until you do get a reading. When you do get a reading, it will more than likely show the same reading meaning that the power is getting to the control board but the control board is faulty and will need to be replaced.
If moving the probe around still doesn't produce any readings, this would indicate there is a fault between the plug and the control board and that is most likely to be in the wiring.
One thing to consider if you do need to replace the control board is that many manufacturers make their control boards so that they have to be programmed when they are fitted. This is possible for you to do but it may require purchasing additional equipment and this can be expensive. It's best to check your user manual before you begin this repair.
Problem: Dishwasher blowing fuse when you turn it on
The next thing we're going to look at is if your dishwasher is blowing a fuse when you turn it on. In most cases, this is going to be caused by the presence of a short which can either be in the control board or in one of the components elsewhere in the dishwasher. In most cases, this is usually the heater. Here's how to find out:
Check 1: Test for a short
Test for a short by using the multimeter to test across the live pin (bottom left) and neutral pin (bottom right) or live and earth pin (top). A short will show up as less than a couple of ohms.
If you do get a reading of a short circuit, try disconnecting the heater and test the plug again to see if the short is gone. If the reading is much higher, it will show that the short circuit is due to a faulty heater. You can confirm this by testing the heater itself. For a working heater, the reading should be somewhere between 20 and 50 ohms. Any reading that is significantly outside of this would indicate that it has developed a short circuit and you will need to replace the dishwasher heater.
If your dishwasher has a flow-through heater, you can view how to replace it here.
Problem: Programs and fault codes
The control board in most dishwashers responds to problems with fault codes. This can be through a combination of lights, letters or numbers. If an error code is displayed it could help you with your diagnosis. Manufacturers use different fault codes so it can be just as beneficial to watch the dishwasher and see when, in a cycle, it stops to determine when the fault is occurring.
Check 1: Leakage
The first point when your dishwasher might register a fault is when you turn it on. If water is leaked into the dishwasher, it may register this as a flood. You will hear the drain pump whirring continuously as it tries to get rid of that water. You can check to see if there is any leakage by tilting the dishwasher onto its side and watching to see if any water drains out of the bottom. If it does, you can take the base off of the dishwasher and check the pipes inside for any damage. It may also be that the detergent has simply foamed too much and that has caused the leak.
Whatever has caused it, be sure to get rid of any water or anything that is causing it to leak. Then, put the base back on and turn the dishwasher on to see if that has resolved the problem.
If it hasn't, take a look at our article on how to diagnose leaks in your dishwasher to get to the bottom of the problem.
Check 2: Where in the cycle your dishwasher stops
When you have turned your dishwasher on and closed the door to start the cycle, the first thing that happens is the drain pump turns on. Any liquids that have run out of glassware or crockery is drained away which takes about 20 seconds. After that, the inlet valve turns on and the dishwasher starts to fill with water until it is just below the door seal. Once it has hit the correct level, the wash pump turns on and you should hear a familiar 'whoosh' sound as the water is sprayed around the dishwasher. After that, the heater turns on if required. Shortly after the heater turns on you'll hear that very familiar clink noise as the dispenser opens and lets the detergent into the dishwasher.
The rest of the wash cycle consists of washing, draining and heating followed by the drying cycle. Some dishwashers use a fan in their drying cycle to circulate air around the cavity and help the water evaporate from the crockery. Other dishwashers simply rely on the residual heat within the crockery for the water to evaporate off.
Failure to complete any of those parts of the process will result in the dishwasher stopping and displaying a fault code.
We hope this article has helped you get to the bottom of the fault with your dishwasher. If you suspect something different might be causing the problem, you can head over to the dishwasher section of our Advice Centre. You can also view how-to videos on diagnosing, fixing and maintaining your household and garden appliances by subscribing to our YouTube channel.
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