How to Diagnose Washing Machine Control and Program Problems

Modern washing machines all contain a computerised timer and this is responsible for controlling all the different circuits in the machine, such as the drain circuit and the heating circuit.

If you suspect that there’s a fault in one of the circuits in your machine, it’s usually much easier to test all the components in the circuit then trying to prove that the problem lies in the control board.

For example, in the drain circuit, you would check the drain pump and the wiring, while for the heating circuit you would check the element, the thermostat and the wiring.

If you then suspect that the problem still lies in the circuit board, unfortunately, it’s usually quite difficult to test the board and you’ll actually just need to replace it altogether.

In this video, we will go through some of the various ways in which you can try to diagnose the problem you are experiencing with your washing machine.

• Multimeter (digital or analogue)

Safety First! Please make sure that you have switched your appliance off at the mains before starting your repair. 

Most modern machines are designed to shut down if they detect a fault somewhere in the system and this is usually accompanied by a fault code. A fault code is displayed on the front of the machine as a combination of letters and lights or numbers.

These fault codes vary from one manufacturer to another, so it can actually be just as helpful to watch your machine to diagnose where the fault is - such as in the drainage circuit or the heating circuit.

When you turn your machine on, the first thing it does is to lock the door and it’s then that it may perform a self-check.

If in the self-check it detects a fault somewhere in the system it’ll shut down and may display a fault code, or if the door doesn’t lock properly it’ll also detect that as a fault and not start the cycle.

Once the machine has passed the self-check stage, it will proceed to fill with water through the solenoid valves at the back. Most stages in a washing machine cycle are programmed to complete within a predetermined time.

If your machine doesn’t recognise that it’s filled within a couple of minutes it will usually shut down and display a fault code to stop any flooding occurring.

Assuming the machine has filled with water as it should do, it will then move on to the next stage in the wash cycle. Once the water has filled to the correct level, the machine will then start to agitate it and heat it if required by that particular cycle.

When the temperature has been reached the machine will then wash for a certain amount of time before draining the water away. Again this has to happen within a predetermined time so if it doesn’t, the machine will shut down and display a fault code.

Once the water is drained it will then do a short spin, followed by then performing the rinse cycle. The rinse cycle is very similar to the wash cycle, water is brought into a predetermined level within a certain amount of time, it’s then agitated before being drained away.

Most machines have at least two rinses in the rinse cycle - and on the final rinse both solenoid valves at the back of the machine open up and flush any conditioner from the detergent drawer down into the drum.

Once your machine has completed the rinse cycle it will prepare for the final spin by balancing the load, and it does this by attempting to evenly distribute the weight of the load around the drum.

However, if the load contains a particularly heavy item - such as a pair of jeans or a towel - amongst an otherwise lighter load, it will attempt to balance that heavier item amongst the load.

If it can’t balance the load it will simply refuse to spin or it may just shut down and display a fault code. Once the load has been balanced the machine will spin and complete the wash cycle.

If your machine is dead and it’s not displaying any lights or anything on the front, then you’ll need to check it for continuity.

Firstly, just unplug it from the wall and have a look at the fuse inside the plug to make sure it hasn’t blown, if you’ve established that it hasn’t, then you’ll need to check for continuity between the plug and the control board.

Follow the path of the plug in through the machine, it comes in here and through this filter board here, it then passes along these cables to the plug on the control board here. Grab a multimeter on a resistance or continuity setting, and just check for continuity between the two.

On this particular example in the video, you can see that there’s continuity on the two connections (this means that the power is getting to the circuit board) There’s probably a fault inside – and the way to check is this by replacing the board with a new one.

The Machine Blows A Fuse When Plugged In - Checking For A Short Circuit

When a fuse is blown, it is caused by a short circuit somewhere in the machine and this short can either exist in the control board or within components around the machine.

You can easily check for a short by just unplugging the machine and then using a multimeter on a resistance reading to check for the short across the plug - through live and earth, and live and neutral.

If there is a short there it’s going to show up as a resistance reading of less than a couple of ohms.

Short Circuit - Checking The Heating Element

Often the first thing to short is the heating element, so try disconnecting that and testing again for a short circuit - if the short has gone then that would indicate that the short does lie in the element.

You can always double check by testing the element itself - for a working element the reading you’re looking for is somewhere between 20 and 50 ohms (so obviously anything outside of that reading means you’ll need to replace the element).

To test the element, first disconnect the lugs and then turn your meter onto a high resistance setting and measure from earth to one of the terminals – from this you shouldn’t get a reading.

Proceed to put your meter onto a low resistance setting and measure across the element. On this element there is a reading of about 27 to 28 ohms, so that indicates that this one is OK.

Short Circuit - Checking The Circuit Board

If when you have removed the element it doesn’t get rid of the short, the next thing to disconnect is the circuit board. Once disconnected you can then check for a short there.

If the short still hasn’t gone, move further along the line and try checking on the filter board. If the short still hasn’t gone then it’s likely to be in the plug and the cable and you’ll need to replace those.

The Machine Is Tripping The Electricity

If your machine is tripping the electricity, the process for diagnosing is largely the same - however, it may be that a normal meter won’t show any fault being present.

In such a scenario an engineer would use an insulation tester such as a Megger, and this produces 500 volts for determining where the breakdown has occurred.

Again, it’s likely to be due to the heater or heaters if it’s a washer-dryer appliance, but if the tripping is occurring during the final spin then it is the motor that is likely to be at fault - as this is where it’s being worked at its hardest during that part of the cycle.

Diagnosing Faults With Control Boards

One final thing about control boards and tripping faults is that a lot of the time it can be difficult to conclusively diagnose the fault, sometimes a fault that’s being caused by another component actually appears to be caused by the control board.

Similarly, if you’re replacing the control board, many of them now require professional programming on installation - so for that reason, you may prefer to use a fixed-price repair service, such as Repaircare. Final Comment From eSpares:

Well, there we go, video over! Hopefully, you will have found it useful in helping you identify the issue with your washing machine. Just remember though, for all your washing machine related needs, you can visit the Washing Machine area on the eSpares website to obtain spare parts for your washing machine - as well as viewing lots more helpful articles and videos in our Advice Centre.