If you are anything like me, you do not like to turn away any vehicle that comes to your shop for service, even if it is a hybrid vehicle. Customers will call my shop all the time and ask, "Do you work on hybrid vehicles?” Of course, I respond with, "Absolutely." Why wouldn't we? They say, "Oh, thank god. I called three other shops, and they said they do not service hybrid vehicles." If you have a shop or work in a shop that turns away hybrid vehicles, I have some good news for you. In this article, I am going to share some tips and tricks that will help you become more efficient and profitable when serving HVs.
How a hybrid vehicle works
Like any vehicle, we have to understand what we are up against. Let's get started with some basics. How do HVs work? Simply put, HVs utilize a gasoline-powered engine coupled with an electric motor that propels the vehicle to move. It is as simple as that. Now, we all know how a vehicle's charging system works. HVs are very similar, where they take one form of electricity and convert it into another form that drives the electric motor while at the same time recharging the vehicle's battery and operating the vehicle's electrical components. Ok great. Now that we have some basics out of the way, let's look at some ways we can make HV repair more efficient and profitable. Oh, and of course, safe as well.
Safety first
Starting off with safety, there are many different tools to help keep you safe when you are servicing HVs. The number one, and by far the most important, tool of them all is ... your brain! As long as we stay aware and understand what we are working on, that can help keep us safe, along with the appropriate PPE, of course. As we see in Figure 1, we have some of the safety tools used when servicing HVs, which include insulated gloves, insulated hand tools, and a minimum Matco CAT 3 DVOM. Insulated gloves will keep you safe from any arcing and risk of being shocked if you happen to touch a live high voltage circuit. A CAT 3-rated multimeter is designed to withstand high-voltage inputs and has arc protection capabilities. These tools are specifically designed to help keep us safe while servicing HVs.
Servicing hybrid vehicles
Now the real fun begins. It is time to dig into servicing HVs. Have you had an HV that would not stay running while you are trying to diagnose it? I know I have experienced this, and it can be very frustrating. The good news is that there is a way to deal with this annoying feature while servicing HVs. By putting the vehicle into a feature called Service Mode this will keep the engine running while trying to diagnose it and allow the vehicle to idle for an extended period of time. The procedure to put these vehicles into Service Mode is kind of like putting a cheat code into a video game from back in the day. (Depending on what era you grew up in, of course.)
Let’s look at an example. On a 2015 Toyota Prius, I executed this procedure. Put the vehicle into the accessory position, depress the accelerator pedal twice, shift to park, and depress the accelerator pedal twice again. Now you can see my reference to the video game cheat codes (Figure 2). This is a good lesson here about how important it is to have the ability to reference service information. This procedure will vary from manufacturer to manufacturer, so make sure you check how to do this for whatever vehicle you are working on.
Handling high voltage
Moving on, we will get into disconnecting and isolating the high voltage battery. All HVs will have a service plug that can be taken out and will isolate the high voltage battery cables (Figure 3). This will allow you to safely service the vehicle in the areas where high voltage is present.
We will take a look at different manufacturers' procedures to disconnect the service plug. We always want to use our CAT 3-rated multimeter and check for any voltage, present at the service plug connector.
As seen in Figure 4, we have a 2015 Hyundai Sonata 2.4L hybrid's service plug location. There is not much to it: disconnect the vehicle’s 12V battery, then locate the service plug, and pull it out. Always wait 10 minutes after removing the service plug; this will allow all the capacitors inside the inverter to drain, making it safe to continue with service.
Replacing a hybrid battery
For the final service tip, we will look at a procedure demonstrating the replacement of a hybrid battery in a 2014 Hyundai Sonata 2.4L hybrid. As we discussed above, first, we’ll reference service information – in this case, I’m using ALLDATA – to find out the location of the service plug. Next, we will disconnect the 12V battery cables. Now, using our HV-insulated safety tools, we access the service plug and disconnect it. We can then wait our ten minutes to allow the capacitors to drain. From this point, we can safely remove the HV battery assembly from the vehicle. Once you are able to do one HV, you should be able to do any of the different makes and models.
Another important aspect of servicing HVs is the ability to accurately and efficiently diagnose different issues within the hybrid drive system. As long as you have a basic understanding of how an automotive electrical system works, then you will have no problem diagnosing the hybrid system. All the same principles apply as the 12V system, the only difference is that we are dealing with a higher voltage level. Referencing wiring diagrams, we can understand how the system we are dealing with functions. HV systems are very code-driven due to the advanced monitoring of all of the systems. This means we can use the trouble codes as a great diagnostic direction while troubleshooting different faults. Scan tools are also very useful when it comes to diagnosing HVs. For example, if an HVs battery’s SOC (State of Charge) becomes lower than twenty percent, certain models will disable starting. When this happens, a function on the scan tool called “Force Start” can be used to force the vehicle to start to charge the hybrid battery.
Conclusion
To wrap up, I hope this article helped you see that servicing HVs is not as hard as it seems. Like I said earlier, turning away vehicles does not sit well with me. We are professionals in the field of repairing automotive vehicles and should be able to service all vehicles, no matter how sophisticated the systems on the vehicles become. My goal in this article was to show a simplistic way of looking at a rather complicated system and the tools and equipment used to help aid the industry into servicing hybrid vehicles rather than turning them away. We can also take some of these tips and apply them to non-hybrid vehicles. A lot of the skills displayed in this article are universal across the automotive repair realm. Cheers to more vehicles and more profits coming into your shop or bay!
