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Old 01-24-2021, 01:23 PM   #1
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Transit 2020 AWD EcoBoost parasitic current

My Transit Parasitic current draw.

As I have been working on the new camper, I have noticed excessive battery drain on my new 2020 AWD Transit. I did take it into the ford dealer once and they found nothing wrong but did replace my batteries. It is hard to tell if the problem was always there, because admittingly it doesn't get driven much.

I first just put a monitor on the battery to monitor the voltage. Victron makes a relatively cheap monitor temperature and voltage with Bluetooth.

It worked well I could read it from inside the house and keep tabs on the voltage. It's real purpose is to pair with a Victron Solar controller to report battery voltage and temp back to the controller. As expected the drop was much more than I would have expected. So on to phase two

Phase two I decided to at current monitoring into the mix, for this I used phidget Single Board computer (Much like Arduino), a voltage sensor and current sensor. The Phidget SBC has the capability of being attached via WIFI, so I could now check from my office. I wrote a quick program to read the sensors and display the information, but also to record and log the data.

The current sensor I am using is a 0-50 amps 1% accurate sensor. I have not yet calibrated in the van, so it's accuracy could be in question, but I was looking for trends not just a momentary current reading.

Anyhow over a 16 and 1/2 hour log , the voltage dropped from 12.8 to 12.27 volts. More importantly this was the chart I got after looking through the log data. For the record, the data is reported and logged every 1/2 second. So while the current spikes you see are not extremely long, they are very repetitive, in fact in very 1 hour and 34 mins. You might notice one spike out of sequence, that is where I made sure the van was locked up for night.

and a close up

Well I need to do a little more work on verifying the accuracy at the low current draw, but there is no doubt the spikes are there.


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Old 01-24-2021, 10:12 PM   #2
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I too have noticed a significant parasitic draw on the engine batteries of our 2019 Transit 350. Our van is not a daily driver, either, and will sit for ~10-12 days between excursions. The first time I checked the battery charge status after 15 days in our driveway, it showed 12.31 V /50% SOC. I haven’t measured current draw yet but am planning to install a battery monitor similar to what you have done. Apparently, with the Ford onboard computer system, many monitoring components continue to use considerable amounts power during periods when the van is not “in use.” Our LiFePO4 house batteries continue to hold their charge nicely with the house system turned off during these periods. I purposely did not connect the starter and house battery systems together except for a one way DC-DC charger via the alternator. It is tempting to try and disable some of this “unnecessary” monitoring using FORScan, but not having any sophistication in understanding the onboard computer, I am going to pass on this option. Every 10-14 days I am using a trickle charger to charge and top off the dual starter batteries and I carry a charged Audew jump starter in the van, just in case. (As posted on this forum: )
I will be interested to learn from you about the sources of these ongoing current leaks.


2019 Transit 350 HR Eco Quigley 4X4
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Old 02-05-2021, 12:54 PM   #3
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After looking more closely at my data it became clear that current spike while of interest, were not the main problem, the high idle current draw was actually worse then what I was showing. To be clear the draws were outside of the values that I would consider parasitic loads. I actually matched the current draw with other meters and added the ability of my program to count amp-hour data. This would enable me to sink the amp-hours with the voltage of the battery bank.

After taking it for a half-hour drive last week, I found that the system had returned to what I expect is more normal. I added a temperature probe to my setup, to see if I could determine if temp had any significant cause in this problem.

The last thing I added to my setup was the ability to turn on/off the charger (Small Victron 15-amp charger). One thing you may notice is that the current probe does not include current coming in from the charger.

This morning I woke and found a high constant current draw on the program. When I checked the van I found that my headlights were on. I turned them off by cycling the "lock button" on the key fob. A few minutes later they came back on, so I turned on the power supply. This was in hope of stopping the cycle, which it did. This was also something I had previously seen. The important thing now is that I have data to provide to Ford when I take the van back in. My plan going forward will be to remove the connection of my AMP Research PowerSteps from the equation, although I have little concern that they are having a impact. But I would prefer to remove any question from Ford the next time I take it in. The last time they had it for 4 days and said they couldn't find anything.

This is what I believe normal parasitic load probably looks like.

This is the data showing the data collected as the Headlights decided to come on by themselves overnight. Obviously the headlights coming on can be a large current drain.

If interested here are the changes made to my data collection program.

And the here is what the setup[ actually looks like.

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Old 02-05-2021, 02:19 PM   #4
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Now that's pretty amazing, and odd as far as the headlights go.
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Old 11-19-2021, 09:40 AM   #5
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Round #2

Well with the changing seasons, the random headlight issue and excessive parasitic current draw has come back. There was some hope that an unrelated update for the BCM would take care of the issue. That, pretty much as expected was found to be untrue. Luckily during the summer, I included two ways to charge my starting battery, a shore power charger

and solar charger option.

So at least I can keep the battery from being destroyed. (Wrong)

So back to the hunt. I pretty much realized that taking this back to Ford to track down would be fruitless, so I decided to dig in. In a previous life I worked on some complex issues, and the first rule of debug was to try and make the problem repeatable. Luckily for me with return of wet colder weather that has pretty much turned to every night.

One thing I looked at was the fact that rain returned. I know most people think it rains all the time here in Oregon. If you spent any time on the Transit Forum you heard of the water in the air filter issues. So, I did spend some time looking into this, mainly because the return of cold hit before the rain. I didn’t relay see the issue until I had both. That issue was I believed fixed in 2019, but it does get wet inside the engine compartment. I did clean out the weep hole and added additional hole for the windshield cowl draining system. I added a cover for a suspected connector, to keep it from getting wet. That appeared to be a red herring, as the problem was still prevalent.

I also completely disconnected the power steps, as they must sniff the CANBUS to determine if the door is open or closed. The power steps were added after first seeing this issue, so I was confident they had no issue with the problem. If I do have to back to Ford, I want to rule out any 2nd party culprits and keep the focus on the real problem. So, this may give you some insight to as where I am going the CANBUS. Unfortunately, or fortunately modern vehicles are dependent on CANBUS communication.

As you can see, there are five major Buses in this vehicle, a couple of high-speed busses and other medium speed buses. This doesn’t even include some of the private busses between modules. The gateway module is where all these buses come together, as it can also transfer information from one bus to the other. The gateway also has the DLC connection (OBDII) port connection.

The bus that I focused my concern at was HS1 CAN. It has the modules that are most likely involved in this issue, mainly the BCM, but it would be possible for an issue to transfer from one bus to the other. My first thought was to put a can bus sniffer on, to see if I could find out who was sending the BCM a bad message to turn the light on. That would be prudent, but you would have to catch the failure and have the documentation to understand the messages being passed. While I have a basic understanding of the protocol, it is not easy to get the information needed from Ford. Reverse engineering could take a sometime.

I was also using the data I had from capturing current data last year. That data led me to believe the problem was a possible bus problem as it would happen when there was known bus activity or at least I perceived there was activity based on the time cycle seen. The fact that temperature & humidity had a large effect on the issue. I spent many years running equipment in temperature chambers, so no convincing needed.

My next thought was through a scope on the bus to see if anything looked out of the ordinary.

Unfortunately, I don’t own a scope, and while I’m always looking for a reason to get one, I’m not sure this rises to threshold to purchase one. At least not yet.

I still have a few things I can do with a basic DVM, one would be to measure the voltages of the HS1 CAN +, and HS1 CAN – lines, that would be relatively easy, but determining that data depends a lot on the knowledge what is going on bus. So that leaves us with basic measurement on the termination of the bus.

CAN stands for Controller Area Network and it runs on a 2-wire high speed bus. To prevent reflections on the bus, it needs to be terminated on each end of the bus. Going back to one the previous diagrams you can see where the termination for the HS1 Can bus reside, the PCM module and the Gateway module.

When you go to measure these, you are going to need “needle probes” to easily get to these connectors, these will allow you to back probe the connectors. I couldn’t find my older needle probes, so I had to order some. While I was waiting, I took the Communication module off, and measured all the bus connection to verify that they have a 120-ohm resistance between the HS1CAN - and HS1CAN +, I check all the can busses going to the module.

I got my needle probes and was able to measure the connector going to the Gateway Communication module. The bus that I am looking at are pin 19 & 20, when I measured this, I got 60-ohm.

This was surprising in that I was expecting 120-ohm. 60-ohm would be what it should measure if the Gateway module was connected. Two 120-ohm resisters in parallel would equal 60-ohms, this leads one to believe there is an extra termination on the bus. Of course, to be sure, I connect the gateway module and measure between high & low and get 42-ohms.

I must say that I was kinds of surprised, as it seemed to simple. When checking the bus, you are really looking for something between 55 & 65 ohms. 42-ohm seems pretty far out, and for the most part this major bus has not shown any errors.

From the diagram above you can see that this bus goes all over the van. It seems like a simple divide and conquer attempt should be the best way to move forward. Seeing that the PCM is supposed to have the other bus termination I decide to go to a connector that I already know is easy to access C139. This is the same connector I thought might have moisture issues

Now when I remove this, I am really expecting to see 60-ohms on the bus, thinking that issue is on the other side of the connector. Instead, the issue travelled with the PCM side.

Connector C139

Bus with C139 Removed

I then moved to remove the AWD Module, no change in issue. So that kind of leaves me with the PCM. I thought about re-flashing the PCM, but with a bus termination so far out, I was afraid of the quality of the update. I decided to make an appointment with the dealer to see what they have to say.

My appointment didn’t go well, it was pretty much a replay of the first time I took it in. Yes, we believe there is a larger parasitic draw. You have stuff hooked up to it (Chargers). One out of your dual batteries is bad. The BCM might turn the lights on if the battery is low. I never received an answer about the Can-Bus termination. I will regroup, I made an appointment to another Ford dealer as I need to collect data for Lemon Law data.

Thanks for letting me vent.
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Old 11-20-2021, 08:47 AM   #6
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Frustrating Greg, I appreciate you sharing all of it though. Good intel for us new Transit fans. We have a new vehicle in the driveway and I am blown away at just how much voltage they take and how things do their own thing long after you shut off the vehicle. I had her new car on the lift a few days ago just looking around and some sort of little electric motor, some emissions pump or something, ran for an hour or more after I shut it off. I have also walked by many cars, my own and others, long after they have been parked and can hear some buzz or small motor/fan running long after they are cold.

I know this is not an ideal but if we are talking camper vans that are not daily drivers and have a house system separated from the chassis electrical system would it not work to just use a battery disconnect at the main battery? The house system/solar could go on doing it's thing plugged in or solar but the chassis side would be completely dead until you got ready to go somewhere.

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Old 11-23-2021, 10:25 AM   #7
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I should change the title of the thread; it is not really a parasitic load issue. In fact, that is part of the problem, as the diagnostic tree takes them down the same fruitless path. The video above doesn’t help you trouble shoot this issue. They are convinced that parasitic draw drains the battery, and then the BMC module goes haywire and turns on the lights. So sure, a battery disconnect would be an be an option, in this case it would just be masking another problem. There is also no reason, that failures can occur while the vehicles running.

I also don’t want anyone to think my issue is a reason not to purchase a Transit. The complexity seems scary, but in many ways, it makes things easier. I was able to use FORScan and run diagnostics on all the modules that I had concerns about.

My frustration with this issue, was really the last response I received when I took it in. I specifically stated that my issue was that the HS1-Can bus termination was wrong. Unless they could show me a reason for the value, I believed it should be corrected. I believe it most likely the cause of my intermittent issue.

Their focus was instead that there was a parasitic load that drained the battery, after the battery got so low the BCM would inadvertently turn on the headlights. This vehicle is amazing, and monitoring the battery is something it does well. I can use FORScan to read the SOC level of the battery bank. This thing already turns things off as the battery lowers, certainly it could be smart enough to not self-destruct and turn on the head lights. They act like this is a feature not a bug.

On the other side of the equation, I understand corporate structure and the impact on these types of issues. I used to work as a validation engineer (got to break things for a living), I would sometimes get called in on customer issues. By the time I was asked to be involved the customer was already frustrated, the field team had gone through their documented process to isolate the issue. I am sure the process worked 90% to 95% of the time, the problem is the 5% that it didn’t.

Getting a time slot at a dealer is difficult today, it took a week to get the last one. The lack of new cars has many old cars in the shop, turn around is slow due to part shortage. All this adds to the frustration on both sides. They needed a reason to get my vehicle out of the shop, as it was taking up space.
It took less than 48 hours for me to reproduce the failure once home with the new batteries. I was able to start the vehicle with the remote start through my phone app. That Fordpass™ connect is one of the first things that gets shut down as the battery voltage gets lower. Running the vehicle for 15 minutes usually gets it trough the rest of the night. I suspect this is because the termination value of network increases slightly due to temperature increase from engine heat, therefore explaining why it generally doesn’t happen in the summer.

From all available information the bus should measure between 54 & 66 ohms, mine measures down around 42 ohms. (SECTION 418-00 Module Communications Network) The termination is supposed to minimize reflections on the bus, these reflections could possibly change the data of the message being sent. The fact that I am only seeing intermittent problems actual speaks well for the system. If I felt it was necessary, I would already have put a sniffer on the can bus and tried to capture the offending command that turns on my lights. It would be a fun project, if had the van garaged and nothing else going on. Out in my driveway not so much.

I have documented six failures since it has been back from it’s resent trip to a ford dealer. I have logged the battery voltage at the time of failure, it happens even when the battery is on a charger. I will make sure to remove my cable for charging from CCP and take it to another dealer (this one I’m told is used to working aftermarket vehicles like campers). If my results are the same, I will then take it to an independent shop, that will hopefully look at things I want looked at. If it wasn’t for it being under warranty, I would already be there.

I would have no problem with someone telling me I was completely wrong if they fixed the Van. I also feel sorry for the standard customer that doesn’t have some of the knowledge I have.
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Old 11-23-2021, 11:42 AM   #8
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I understand that it's a risk (of breakage) but have you taken the circuit board out of that module's housing and located the resistor in question? I don't have nearly the patience you seem to have here. I would have that mofo on my bench with the solder station blazin' by now.

If you've isolated the module, what is the part number? I'm going to harvest some parts out of a salvaged 2020 Transit soon, maybe I can grab a spare for you.
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Old 11-23-2021, 01:22 PM   #9
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The module in question is the PCM, not really ready to do self repair on it yet. It's not a daily driver, so it hasn't really impacted life as much as it could. I get it, and believe patience is not my strong suit. My soldering skills were really good at one time, but technology and my eyesight has passed me up. If I thought it was thru hole technology I might try, it is most likely surface mount. If I F it up, it is a real brick.

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Old 11-24-2021, 03:12 AM   #10
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WAY out of my league here but just throwing it out:
Circuit board mount creating flex?
Wire ties/ wire bundle securing methods creating crush?
Wire to pin termination?

All could create resistance issues??

Beastie 3: 2002 7.3 EB Cargo: Agile TTB, CCV Mid Top, Custom Walk Through, Lots of stuff added.
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