April 22

2015 Fiat 500E, Battery Coolant Heater



Mark: Hi, it's Mark Bossert. I'm here with Bernie Pawlik. Pawlik Automotive in Vancouver. Vancouver's best auto service experience. 25 times voted best auto repair in Vancouver by their customers. And we're talking cars. How you doing Bernie? 

Bernie: Doing very well. 

Mark: So today is another electric vehicle, a 2015 Fiat 500E. What was going on with this car? 

Bernie: So this vehicle came in with a warning light on the dash, not a check engine light, but a warning light, sort of top of the instrument cluster, the client was concerned about. The vehicle was working fine otherwise, but there was a concern about the light. 

Mark: So what kind of diagnosis do you do on the EV Fiat?

Bernie: Yeah, so first of all, determining what the light is for, and it's for an isolation fault in the high voltage electrical system. So this is a warning that there's possibly a serious fault occurring. So our testing and diagnosis is to plug a diagnostic scan tool in, retrieve stored codes from the vehicle computer and we found one for a isolation fault in the high voltage system. So from there, it's a matter of actually doing specific testing to find out what that isolation fault is. 

Mark: Can you explain what an isolation fault is? 

Bernie: Absolutely. So high voltage EVs, you know, the batteries are high voltage, anywhere from 250 up to 800 volts in some cars. Fiat's somewhere around, I think, the 300 volt range. So, I mean, that's dangerous voltage. If you touch that, it can kill you. So dangerous. So when they make the vehicle, anything that's part of the high voltage system is isolated from the chassis of the vehicle so that voltage can't leak through somehow.

And so when there's an isolation fault, that system that the, system monitors everything has basically determined that there's a fault. That there's a possible leakage of high voltage to the chassis is imminent. So that's what we have to test for. We have a special piece of testing equipment where we go through basically each component in the high voltage system and figure out which one of those components is the item at fault. Doesn't show it on the scan tool, like people think, Oh yeah, you plug it in and it'll just tell you what's wrong. It only tells you the area that the problem is. It doesn't tell you what the actual problem is. So that's where our testing comes in. 

Mark: So what component did you find at fault? 

Bernie: So we found the battery coolant heater was the component at fault. I mean it's sort of a process of elimination when we have to Isolate the various components by disconnecting them and following the manufacturer's procedures.

And when we disconnected that particular component, that's when the fault went away. So we knew it was in that particular unit and it needed to be replaced. 

Mark: So what's a battery coolant heater? 

Bernie: So basically this is an item on an EV. To charge a battery properly in cold temperature, well in any temperature really the EV battery has to be a certain temperature. Best one's not too hot. Best one's not too cold. I mean, you can't pump the electrons into the battery properly under, you know, the wrong conditions. So the battery coolant heater ensures that the battery is at the right temperature for charging. And there may be some other uses for it as well to maintain a certain temperature, likely in cold weather.

But you know, obviously in cold weather, but that's basically the function of this heater and it's an electric heater, so it will actually use battery power to warm the coolant up to actually get it to the right temperature. 

Mark: And I'm sure the batteries are going to get hot if you're driving really hard for a long time too. So the coolant part of it is going to come into play then? 

Bernie: You know, I'm not sure because sometimes they actually use a chiller as well to actually, you know, part of the air conditioning system to actually cool the battery down. So there are separate components and to be honest, I haven't looked in great detail at all the components.

I know there's a chiller on this vehicle as well So that might be used in the battery system as well. But for the purpose of this podcast I mean we're talking about an isolation fault in a particular component in the battery coolant heater. 

Now the interesting thing is it wasn't disabling the vehicle from running and I would say that if the fault was even more serious It might disable the vehicle completely from even starting or powering up. How the whole computerized system works on that, nonetheless, there's a fault here that it's worth fixing for safety sake.

Mark: So let's look at some pictures. 

Bernie: So this is our battery coolant heater. This is actually the unit installed in the vehicle. So this is sort of buried under the right, the passenger side front wheel well area, and that's where the coolant heater is. That's basically the unit right there. It's bolted up to the side of the the motor assembly.

2015 Fiat 500E, Battery Coolant Heater

This is a view of the old unit taken out. Anything with orange cables and plugs, that's all the high voltage component of the system. The wires are fairly small for an EV. So this doesn't draw a massive amount of current, which is good because it would take a lot of battery power. There's another connector plug on there, which would go to the vehicle computer system. And then there's a ground strap connected to that as well.

2015 Fiat 500E, Battery Coolant Heater

And another view of the unit there. You can also see there's a little sort of at the bottom right of the heater unit right there. That's where 1 of the coolant pipes goes. 

2015 Fiat 500E, Battery Coolant Heater

There's another 1 exactly opposite on the backside. And that's basically our picture show.

Mark: So I guess, is it just replacing the unit? 

Bernie: Yeah, we have to basically, yeah, it's replace the unit. It looks like you could clip it and take it apart, but I mean, what can we fix inside of it? There's nothing there and there's a risk that if you do repair it, maybe the repair isn't going to be proper and it's going to be back again. So it's a basically replace the part. And there's, you know, at this point, two options, new or used. Our customer opted for the used option because the price was substantially better.

I'll say that, you know, this part is about 5,000 dollars Canadian to replace it. Very expensive part for something that's obviously not much of a part. 

Mark: Was there any programming of this component? 

Bernie: No, it's plug and play. So that actually made for a fairly straightforward repair. Once the diagnosis was really the sort of larger part of the process. Coolant has to be bled of course, to make sure there's no air in the system. But other than that, it's pretty straightforward repair. 

Mark: And is this a common fault? This isn't that common of a vehicle. Is this a common fault on this EV Fiat?

Bernie: You know, this is the first one we've seen in our shop, but I've talked with other shops that do a few of these FIATs and they've done them. So it's obviously something that is a failure item. I don't know in EVs in general, but like I say any car, any part, is going to fail at some point in time. You just never know exactly when. 

These vehicles were sold only in California and Oregon for sort of a limited time. A few of them made their way up to Canada, but they weren't ever sold here. But, you know, being just up the coast from Oregon and California, I guess a few of them have trickled up here over time.

Mark: Any information on how reliable these Fiat 500 Es are? 

Bernie: You know, they seem to be fairly decent. But you know, again, this, this one's getting on now. This is a 2015 we're in 2024. So that's nine years old. And it's when, you know, kind of time when things start to happen. I spoke to the owner who was not the original owner, but he said that he'd had the car for a few years. This is the first time he's had to spend any money on repairs. And his question was, you know, Hey, what can go wrong next? I mean, should I keep the car? And I said, well, to be honest, I don't know. It's a bit of a crapshoot, like, you could go for another five or ten years and nothing will go wrong, or, you know, another component of some sort will fail, and then you'll have to fix that. 

Mark: And that's you're speaking beyond the normal stuff like tires and brakes and all those sorts of regular maintenance items that you have to still look after on an EV. 

Bernie: Exactly, and fortunately with an EV there is not nearly as many regular maintenance items to be done as on a internal combustion engine vehicle. Things like oil changes that are not necessary, but there are fluids, there is coolant, there's brake fluid. Brakes don't wear very heavily on EVs because of the regenerative braking, but it's good to have the brakes serviced every two to three years just to prevent things from pads from sticking and you know, wearing out prematurely. So yeah, maintenance is good. And of course, tires tend to wear out faster on EVs than internal combustion engine because the vehicles are heavier. But other than that, you know, it's definitely less maintenance.

Mark: If you're looking for service for your EV, any make or model from anywhere in the world, the guys to see are Pawlik Automotive in Vancouver. You can reach them online at pawlikautomotive.com. You can book right there. They'll get back to you and find out what's going on. Get ready for your appointment. Or you can call them at (604) 327-7112 to book your appointment. You have to book ahead. They're always busy. Pawlik Automotive in Vancouver, BC, Canada. Thanks for watching and listening. Thanks, Bernie. 

Bernie: Thank you, Mark. Thanks for watching.

About the author 

Bernie Pawlik

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