Ford going to do new parasitic draw test

[retrojet]

Thanks HeyBales... that's a big read?! Good info....

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[First Sergeant]

I promised to get back to everyone when Ford completed my parasitic draw test, supposedly using the "new" test. Local Ford dealer had my truck 2 days and when I dropped off the vehicle, the service guy looked at their computer and said he could "see" my battery was at 11.8V. I asked, "covered under warranty", he said yep, all good! OK then. In the shop it went. The next afternoon get a call. Yes, we found a parasitic draw, would you like us to go ahead and locate it? We may need to disconnect your mods to find it. My mods are a two wire "eyebrow light", dash cam (plugs in), and ambient floor lights, two wires. Diagnostic fee will be a minimum $478.00, and if they find nothing, it is NOT covered by warranty. Huh? If we don't find it, we keep going until we do find the draw, but he never said what extra dollar amount that would be. I picked up truck the next day. And the "diagnostic fee for the obviously crap battery still cost me $295.00, but I got it down to $205.00 using some Ford points. Crazy. What happened to "YEP' it's covered under warranty? (I'm now realizing the so called warranty is not all it's cracked up to be. Should have read the 503 pages of fine print) I'll be doing my own diagnostics, but the obvious problem is still the charging profile/software issues on this vehicle, which in my opinion now is will never get corrected. It's been how many years that this problem has existed and Ford has obviously "moved on"? I know about the naysayers here, but when (not if) Toyota makes a similar truck that is Hybrid and flat towable, I will be selling the Maverick. I did tow a Jeep prior and could go back to that if Toyota fails to deliver. We also trailered our Toyota Venza behind the motorhome, and that worked ok, but then you have to park the trailer at RV park and loading car and tying it down get to be a hassle. Don't get me wrong, the Maverick is a sweet truck and I do like it very much. I'm just not willing to agree to sub standard issues that can't be resolved. Not at all impressed with the service Ford provides. My service ticket is attached. Note: the invoice shows battery passed the tests??? What about the 11.8V showing in their system earlier?? I got crickets... when I asked. Manager out to lunch. Good thing, I was about to go all in Army style intimidator and he would be the intimidatee. No fun for me that day.

 

[johnDeere]

I promised to get back to everyone when Ford completed my parasitic draw test, supposedly using the "new" test. Local Ford dealer had my truck 2 days and when I dropped off the vehicle, the service guy looked at their computer and said he could "see" my battery was at 11.8V. I asked, "covered under warranty", he said yep, all good! OK then. In the shop it went. The next afternoon get a call. Yes, we found a parasitic draw, would you like us to go ahead and locate it? We may need to disconnect your mods to find it. My mods are a two wire "eyebrow light", dash cam (plugs in), and ambient floor lights, two wires. Diagnostic fee will be a minimum $478.00, and if they find nothing, it is NOT covered by warranty. Huh? If we don't find it, we keep going until we do find the draw, but he never said what extra dollar amount that would be. I picked up truck the next day. And the "diagnostic fee for the obviously crap battery still cost me $295.00, but I got it down to $205.00 using some Ford points. Crazy. What happened to "YEP' it's covered under warranty? (I'm now realizing the so called warranty is not all it's cracked up to be. Should have read the 503 pages of fine print) I'll be doing my own diagnostics, but the obvious problem is still the charging profile/software issues on this vehicle, which in my opinion now is will never get corrected. It's been how many years that this problem has existed and Ford has obviously "moved on"? I know about the naysayers here, but when (not if) Toyota makes a similar truck that is Hybrid and flat towable, I will be selling the Maverick. I did tow a Jeep prior and could go back to that if Toyota fails to deliver. We also trailered our Toyota Venza behind the motorhome, and that worked ok, but then you have to park the trailer at RV park and loading car and tying it down get to be a hassle. Don't get me wrong, the Maverick is a sweet truck and I do like it very much. I'm just not willing to agree to sub standard issues that can't be resolved. Not at all impressed with the service Ford provides. My service ticket is attached. Note: the invoice shows battery passed the tests??? What about the 11.8V showing in their system earlier?? I got crickets... when I asked. Manager out to lunch. Good thing, I was about to go all in Army style intimidator and he would be the intimidatee. No fun for me that day.

Hello Dave,
Well that sucks big time.
Ford knows they have a problem, and still wants to charge you for a error in there truck.
Do you now have a AGM or flooded battery?
Since you said its time for your own diagnostics.
Its wise to purchase a current/volt meter to connect between the frame ground and to the battery ground.
That way you can see what the voltage and current is just looking through the window or on your smart phone.
From what I am seeing now, there is a charging scheme issue.

It is bull that it may take up to 90 minutes for the hybrid system to totally shut down, where the non hybrid limit is 30 minutes.

And if you drive less than 15 minutes per on-off cycle, that is not long enough to charge the battery back to where you started.

The BMS learn must be done correctly, if not, your giving the truck the wrong info about the battery SOC.
I did find that after the truck get to 90% SOC it changes to holding charge of 12.8v. NOT floating voltage.
That does not charge but maybe discharges the battery.
But that voltage is too low for a floating charge when you driving. so not good.

I found that you can fool the system and turn you cabin fan past 5 and it will start charging at 14.8+ volts.

I also found out that it does not matter if (using forscan), if you set AGM or flooded for battery chemistry, it still charges the same voltage.
Now 12.8v is way to low for the AGM battery voltage, so you probably discharging out of the battery when you driving.

 

[First Sergeant]

Hello Dave,
Well that sucks big time.
Ford knows they have a problem, and still wants to charge you for a error in there truck.
Do you now have a AGM or flooded battery?
Since you said its time for your own diagnostics.
Its wise to purchase a current/volt meter to connect between the frame ground and to the battery ground.
That way you can see what the voltage and current is just looking through the window or on your smart phone.
From what I am seeing now, there is a charging scheme issue.

It is bull that it may take up to 90 minutes for the hybrid system to totally shut down, where the non hybrid limit is 30 minutes.

And if you drive less than 15 minutes per on-off cycle, that is not long enough to charge the battery back to where you started.

The BMS learn must be done correctly, if not, your giving the truck the wrong info about the battery SOC.
I did find that after the truck get to 90% SOC it changes to holding charge of 12.8v. NOT floating voltage.
That does not charge but maybe discharges the battery.
But that voltage is too low for a floating charge when you driving. so not good.

I found that you can fool the system and turn you cabin fan past 5 and it will start charging at 14.8+ volts.

I also found out that it does not matter if (using forscan), if you set AGM or flooded for battery chemistry, it still charges the same voltage.
Now 12.8v is way to low for the AGM battery voltage, so you probably discharging out of the battery when you driving.

Yes, I have a good clamp meter that will do what is needed. Several days ago I changed (Forscan) my battery to read flooded instead of AGM as I do have the original flooded battery. I also moved up to 95%. I think you are correct, makes no difference! I keep my battery maintainer plugged in most of the time and it reads differently many times. Today I drove home about 13 miles, 45 mph. Plugged in maintainer and it started charging at 13.2V. 20 minutes later went and checked and read 12.1V. If I leave it on for several hours, I normally read about 12.4-12.5, but rarely more. A couple times I have gone out there and it was reading 12.8V. The only issue I have had is several times (none within the last few weeks) where the interior lights are inoperative when getting in the truck, but vehicle is still starting and operating normally. I believe that is the battery saver mode. Thanks for the info about the fan trick, will try that. For now, will just have to live with it. Not horrible, but I do realize at some time I will have to install an AGM battery.

 

[johnDeere]

Yes, I have a good clamp meter that will do what is needed. Several days ago I changed (Forscan) my battery to read flooded instead of AGM as I do have the original flooded battery. I also moved up to 95%. I think you are correct, makes no difference! I keep my battery maintainer plugged in most of the time and it reads differently many times. Today I drove home about 13 miles, 45 mph. Plugged in maintainer and it started charging at 13.2V. 20 minutes later went and checked and read 12.1V. If I leave it on for several hours, I normally read about 12.4-12.5, but rarely more. A couple times I have gone out there and it was reading 12.8V. The only issue I have had is several times (none within the last few weeks) where the interior lights are inoperative when getting in the truck, but vehicle is still starting and operating normally. I believe that is the battery saver mode. Thanks for the info about the fan trick, will try that. For now, will just have to live with it. Not horrible, but I do realize at some time I will have to install an AGM battery.

Thank you for the reply post,
Useful info to see what’s going on with your truck.
Clamp amp meters are ok, but to read low current, a shunt amp meters are better.
The next useful tool is a OBD2 to Bluetooth adapter and “car scanner” app on your iPhone, then you can see 12v battery voltage and 12v SOC, and other things.
To fully charge my test battery it was on a smart charger for 5 hours.
My test battery is a flooded deep cycle battery. I can check the specific gravity of the acid to see if it’s fully charged.
Your battery is probably sulfated, so it may need to be replaced to stop seeing sleep mode.
But right now I do not think the AGM battery will like the charging scheme unless it gets updated.

 

[First Sergeant]

Thank you for the reply post,
Useful info to see what’s going on with your truck.
Clamp amp meters are ok, but to read low current, a shunt amp meters are better.
The next useful tool is a OBD2 to Bluetooth adapter and “car scanner” app on your iPhone, then you can see 12v battery voltage and 12v SOC, and other things.
To fully charge my test battery it was on a smart charger for 5 hours.
My test battery is a flooded deep cycle battery. I can check the specific gravity of the acid to see if it’s fully charged.
Your battery is probably sulfated, so it may need to be replaced to stop seeing sleep mode.
But right now I do not think the AGM battery will like the charging scheme unless it gets updated.

After some thought I'm thinking I'll just put up with the inconvenience of the battery maintainer, although it is very simple and quick to throw it on there. If I can get motivated I may just do the old fashioned pull the fuses one at at time thing with a meter connected between cable and post. See if anything moves. Maybe a waste of time, but for now my "Give a Sh!&%" meter is on zero. I'm only 70, perhaps Ford could get off their ass and get a fix before I reach my expiration date!

 

[HeyBales]

11.8 V in their mind is not a "bad" battery yet - though it obviously enables almost all the Battery Saver "features" to max.
Mine has been resting 11.5 couple mornings lately - still no Deep Sleep Mode for me yet.

They need to test at below 40% SOC to decide bad battery - not sure if that is Ford's special scale of 85% max but I think it is, or the more normal SOC scale depending on battery type.
Mine was around 45% those mornings, Ford scale.

According to posts they'll also fail it if it reads higher, but fails the hold-a-charge test the next day after sitting overnight.

The clamp-meter will be unlikely to be accurate enough with mA or low A scale you'll need.
But it likely would be good enough for sitting in car after Fob lock, reaching back every 5 min for 30 min and getting a draw for the going to sleep time. Go longer if you can stand the twisting. Note the drop down.
Just don't go to sleep yourself listening to the gentle clicking of relays!
Need to listen for front fans accidentally turning on, or now it appears EPB calibrations (don't set it), maybe a pump running long.
I guess if you have garage, you can set the locks so you don't have to sit in it, and keep doors open.

I noticed on work-order they did a BCM update - but not the ACCM update related to battery problems. That might be a request to them for why not - unless already done and I forgot that point.

Oh - you can't use pull fuse method - unless you mean going in the correct order so one module doesn't make another sleep, and don't plug them back in. Several systems when fuse is plugged back in - wake back up. So now the 75-90 min starts again.
Easier to use the method you've probably seen of checking V across a fuse, and a table lookup for how many amps that means for fuse size.
Since I'd trust their point there is a parasitic draw above the expected 25-50 mA, you could even skip the check at the battery - just straight to BCM fuses in passenger footwell, and measure and note what's the highest draw.
And then, should that system be on in sleep mode that high?
Or perhaps nothing there - and have to check the bigger BJB.

 

[First Sergeant]

11.8 V in their mind is not a "bad" battery yet - though it obviously enables almost all the Battery Saver "features" to max.
Mine has been resting 11.5 couple mornings lately - still no Deep Sleep Mode for me yet.

They need to test at below 40% SOC to decide bad battery - not sure if that is Ford's special scale of 85% max but I think it is, or the more normal SOC scale depending on battery type.
Mine was around 45% those mornings, Ford scale.

According to posts they'll also fail it if it reads higher, but fails the hold-a-charge test the next day after sitting overnight.

The clamp-meter will be unlikely to be accurate enough with mA or low A scale you'll need.
But it likely would be good enough for sitting in car after Fob lock, reaching back every 5 min for 30 min and getting a draw for the going to sleep time. Go longer if you can stand the twisting. Note the drop down.
Just don't go to sleep yourself listening to the gentle clicking of relays!
Need to listen for front fans accidentally turning on, or now it appears EPB calibrations (don't set it), maybe a pump running long.
I guess if you have garage, you can set the locks so you don't have to sit in it, and keep doors open.

I noticed on work-order they did a BCM update - but not the ACCM update related to battery problems. That might be a request to them for why not - unless already done and I forgot that point.

Oh - you can't use pull fuse method - unless you mean going in the correct order so one module doesn't make another sleep, and don't plug them back in. Several systems when fuse is plugged back in - wake back up. So now the 75-90 min starts again.
Easier to use the method you've probably seen of checking V across a fuse, and a table lookup for how many amps that means for fuse size.
Since I'd trust their point there is a parasitic draw above the expected 25-50 mA, you could even skip the check at the battery - just straight to BCM fuses in passenger footwell, and measure and note what's the highest draw.
And then, should that system be on in sleep mode that high?
Or perhaps nothing there - and have to check the bigger BJB.

It will be interesting to see how much longer my battery will last. While these newer vehicles are much more complicated than what I grew up with, seems they have many more issues that involve long and often expensive visits to the dealer. I see now why some say the dealers don't make money on the sale, they make it on the maintenance. I'm a believer now! Until Ford gets a fix for this charging issue, they won't be getting another dime from me.

 

[johnDeere]

11.8 V in their mind is not a "bad" battery yet - though it obviously enables almost all the Battery Saver "features" to max.
Mine has been resting 11.5 couple mornings lately - still no Deep Sleep Mode for me yet.

They need to test at below 40% SOC to decide bad battery - not sure if that is Ford's special scale of 85% max but I think it is, or the more normal SOC scale depending on battery type.
Mine was around 45% those mornings, Ford scale.

According to posts they'll also fail it if it reads higher, but fails the hold-a-charge test the next day after sitting overnight.

The clamp-meter will be unlikely to be accurate enough with mA or low A scale you'll need.
But it likely would be good enough for sitting in car after Fob lock, reaching back every 5 min for 30 min and getting a draw for the going to sleep time. Go longer if you can stand the twisting. Note the drop down.
Just don't go to sleep yourself listening to the gentle clicking of relays!
Need to listen for front fans accidentally turning on, or now it appears EPB calibrations (don't set it), maybe a pump running long.
I guess if you have garage, you can set the locks so you don't have to sit in it, and keep doors open.

I noticed on work-order they did a BCM update - but not the ACCM update related to battery problems. That might be a request to them for why not - unless already done and I forgot that point.

Oh - you can't use pull fuse method - unless you mean going in the correct order so one module doesn't make another sleep, and don't plug them back in. Several systems when fuse is plugged back in - wake back up. So now the 75-90 min starts again.
Easier to use the method you've probably seen of checking V across a fuse, and a table lookup for how many amps that means for fuse size.
Since I'd trust their point there is a parasitic draw above the expected 25-50 mA, you could even skip the check at the battery - just straight to BCM fuses in passenger footwell, and measure and note what's the highest draw.
And then, should that system be on in sleep mode that high?
Or perhaps nothing there - and have to check the bigger BJB.

Hello Mike
Great write up.
Do we know if there is a cheat sheet for fuses under hood and under foot well that shows amps, and if that fuse number is high or low when the truck is on and off?
I noticed one, but it was not complete.
That list will vary for year and trim.
Its like starting from scratch, well I got current flowing, but what should it be?
I wonder if Ford even knows?

 

[HeyBales]

Hello Mike
Great write up.
Do we know if there is a cheat sheet for fuses under hood and under foot well that shows amps, and if that fuse number is high or low when the truck is on and off?
I noticed one, but it was not complete.
That list will vary for year and trim.
Its like starting from scratch, well I got current flowing, but what should it be?
I wonder if Ford even knows?

I'm sure that's where it's a matter of total draw - if maxing out at 50 mA or abouts - doesn't matter what is doing it - you're good.

I guess they figure any bigger module awake would draw 1A minimum - which I recall from the service manual.
Smaller stuff should be at small mA's since added together. So that's all that would be seen. Seems the bad ones should stick out like a sore thumb. Especially if you stab it with a probe!
https://powerprobe.com/wp-content/uploads/2025/07/Fuse-Charts-Combined-20240826.pdf

I'm still curious what Ford figures is correct after shutoff and before sleep mode - the 60-90 min drowsy mode. Things could still get stupid in there and cause problems.
Thinking of posters hearing hvac fans running, we all know a cooling fan could run for a bit, but how long. The fuel tank pressure is tested at some point infrequently - could that go off the rails with the pump. The silly EBP calibration, what about HVAC damper door calibration. Or the BMS Relearn that has to do a draw test for calculations.
I got down to 0.3 A quickly, or did I. On 1 test time. What about other times?
Ya - they should know what that time period could potentially be, high and low.
1 Ah of draw, and then a short drive the next day - as you've said could never make it up easily. Throw in there inaccurate draw logging for Ah - now you got a problem.

 

[First Sergeant]

I'm sure that's where it's a matter of total draw - if maxing out at 50 mA or abouts - doesn't matter what is doing it - you're good.

I guess they figure any bigger module awake would draw 1A minimum - which I recall from the service manual.
Smaller stuff should be at small mA's since added together. So that's all that would be seen. Seems the bad ones should stick out like a sore thumb. Especially if you stab it with a probe!
https://powerprobe.com/wp-content/uploads/2025/07/Fuse-Charts-Combined-20240826.pdf

I'm still curious what Ford figures is correct after shutoff and before sleep mode - the 60-90 min drowsy mode. Things could still get stupid in there and cause problems.
Thinking of posters hearing hvac fans running, we all know a cooling fan could run for a bit, but how long. The fuel tank pressure is tested at some point infrequently - could that go off the rails with the pump. The silly EBP calibration, what about HVAC damper door calibration. Or the BMS Relearn that has to do a draw test for calculations.
I got down to 0.3 A quickly, or did I. On 1 test time. What about other times?
Ya - they should know what that time period could potentially be, high and low.
1 Ah of draw, and then a short drive the next day - as you've said could never make it up easily. Throw in there inaccurate draw logging for Ah - now you got a problem.

Interesting. I had forgot about some of those things that are similar to the "energizer bunny", just keep on going after Maverick is off. Wife drives 2014 4Runner and Evap pump comes on often after parked, but not until vehicle sets for 5 hours (if I remember correctly). Only runs about 5-7 minutes. No battery issues though. 115K miles, 1st battery replaced about 75K! Not bad for a 11 year old vehicle.

 

[Quest]

One thing I do when looking for a draw is let the car sit overnight with the hood & doors open with
all the latches closed
Then i plug a thermal camera into my phone & go looking for anything warmer than the rest of the car
Whatever is drawing current will also get warm
Doesn't work every time but has worked quite often for me

 

[HeyBales]

One thing I do when looking for a draw is let the car sit overnight with the hood & doors open with
all the latches closed
Then i plug a thermal camera into my phone & go looking for anything warmer than the rest of the car
Whatever is drawing current will also get warm
Doesn't work every time but has worked quite often for me

I guess at the least - fuses with flow should stand out too.
Even if that doesn't spell out what component exactly has lost it's mind, since so many things thrown on a circuit.
But ya - hopefully gives a few to look at.

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