I have a 2018 with 127k, 5LV8, XLT. A year ago the truck started to act like the starter was dragging after the engine warmed up. On the first try it would drag and on the second try would start just fine. Took it to the dealer and they said, "Starter is dragging". They put a new starter on. No change. They said the battery was not holding charge. Put in a new battery, no change. I took it another shop and had the alternator, battery, and starter checked. All were working fine. On two resent occasions the truck would not turn over after several tries. I thought that the new battery might be dead because the charging system. I tried to jump it off but it didn't work. Let the truck set for 30 minutes and it started fine. This past week I tried to start the truck and nothing. dash lights etc fine, turn the ignition, nothing. Starter did not move, no sound, nothing. Checked the battery and it had a full charge. Tried several times that day and the next, nothing. The next day, I tried and it started fine.
I took the truck to the local dealer and they gave me and appointment a month from now. HELP!!!!

 

Check for loose ground cables between the frame and engine, loose positive cable to the starter, and loose control wire to the starter.

 

There is a check you can do off the dash display.
By putting that display in Engineering mode, and stepping to the battery function, you can see the battery state of charge, the voltage during cranking and the voltage charging level after starting if it does start.
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To do this press the OK button and hold.
Turn the ignition on and wait a few seconds for the display to switch over to Engineering mode.
Release OK button.
Use either the up or dn button until you see Battery.
The first voltage you see is state of charge. Should be in the12.2 to 12.7 range.
Then try cranking and observe the voltage. It should not go below 10 volts.
If the engine starts, is the charge voltage 14 to14.7 volts after a few seconds?
The above are normal ranges and are battery state of charge and health dependent.
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Understand, the start method is no longer ignition switch through the Trans switch to the starter.
What is done now is the ignition switch >>request<< a module to activate the cranking function.
This makes remote starting and control much more compatible with the full electronic systems now used since 2004 model year when it was switched to by mandate and refined as time went on.
Now you know a bit more about how it works and what you should see from the power system.
Somewhere in the cranking request chain is the issue.
Good luck.

 

Thanks to both replies. I'll run the diagnostics and report back.

 

Just an add to what Bluegrass said: My first two attempts to enter engineering mode failed but then I realized I wasn't holding down the OK button long enough. Once you're in, it won't come out of the mode until you key off.

it'll take a number clicks down to find battery voltage. What you want to see if your truck won't start is the battery voltage just before your attempt and during the attempt.

If it starts and while you're driving around, engineering mode displaying battery voltage will remain visible to you the whole time. 14.6 volts or about should remain. If you see the voltage drop to 13+ with engine stilling running, consider that a good sign. It means that your battery has charged back up to 80% of full charge and the BMS has tapered down the charge level coming from the alternator.

BMS- Battery management system.

 

Let me add some examples of how much finer you can see what the charge rate is vs Battery age and short time re-charging can be.
Case 1. If many short-term restarts were done, the battery will not have time in charge to recover fully.
In this case, the SOC may be lower than you normally see.
Cranking voltage may go lower.
The re-charge voltage will be higher for a longer time.
Case 2. If the battery has a lot of age, the cranking voltage may be down because the battery resistance is higher due to age.
The re-charging voltage will be higher for more of the time.
Case 3. On a new Battery or for some time after that, the cranking voltage will be closer to 11 volts, and the re-charge voltage >>lower<< around 14.0-1 because the battery is in fine condition and take less to re-charge. Faster cranking may even be noticed.
These are fine points only recognized if you consider all the dynamic operations that can affect the readings.
Case 4. If the voltages are up but cranking is not up to standard, you may begin to assume there is a fault with the start circuit and the Charge circuit likely has no issue. This is a separation observation between the Charge/Battery system and the Cranking.
Case 5. In winter cold temps, the battery conditions are monitored from the Sensor at the battery by the BMS and will >>modify the way the Battery re-charge is handled for any values you see if looked at from the Dash Eng. mode. the reasons are the Battery cannot be charged at fill voltage due to being cold and or Age. This can also be the case in very hot temperatures and could result in a bit shorter life.
When many short time re-starts are done, things get even worse under those conditions.
Most have never heard of Battery resistance but that is actually a measure of health that is calculated by the BMS from monitoring the pre crank voltage to crank voltages to store the rising R value. This is the main reason for re-setting upon battery replacement.

 

Here's my case at noon today.

I entered engineering mode but I started my truck right away. Voltage was 14.6 as expected. 25 minutes into the drive voltage drops to 12.9 and fluctuated from 12.3 to 12.8 up and numerous times. Several minutes later it jumps back up to 14.6 again for a minute or two and then back down to 12.4 to 12.8 again back up to 14.6 for another short period. This up and down of the voltage takes place several times.

Stopped at Burger King for about 10 minutes, truck off. 35 minute time 10 miles

Leaving BK, entered engineering mode again. Checked voltage before cranking engine....

12.2 volts before cranking.
9.6 volts upon cranking. Cranking was as strong as always, startup was right away.
14.6 after start as expected.

From that point leaving BK to go home was was the same as described above. The voltage goes up and down from 14.6 to 12.X and fluctuates in the 12 range.

All I can conclude is that the battery is maintaining 80% and my 3+ year battery does well to recharge. The 9.6 volts cranking is likely just due to age. It seems like the BMS responds quickly when the 80% SOC drops below from what I've observed of the Voltage going up and down.

Yesterday was a different story. The voltage remained at 14.6 the entire 20 mile trip.

About a month ago when outside temps were hot the voltage on the battery remained about 13.4 volts the entire trip. That tells me that the SOC was 80% or better and the BMS was maintaining a trickle charge as described in FORD'S bulletin. As for today, 13.4 volts was only observed a few times. It was quite different than what I expected but all is well anyway.

 

Your running voltage dropping below 14.0 intermittently is a difference I have no explanation for. Check the plug-up at the battery Senor, for seating.
I never saw that action on my system with a two-year-old battery.
The truck systems run in the 14 volt range normally for all the functions, lights etc.....My 02 runs 14.1-14.3 as normal but on a Lead Acid Battery. 13.8 is no longer the standard value.
Those parts that do not run at that level very likely have internal regulators.
If you look at the PCM internal voltage is should never be above about 13.6 to.8. This is what I see with my Scanner connected and the Eng. Mode up, at the same time showing 14v +/- at the time.
Otherwise, the Scanner agrees with the system outside the PCM, so I believe the Scanner is accurate unless proven differently.
A regulator is protection from over voltage from an outside source or cause and for the needs of the internal circuits and devices.
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A hint of an Alternator regulation fault is if the Halogen lights seem brighter than normal or Dim/Brighten as the engine is throttled off Idle, due to the voltage being generated is well above 15 volts and should set a code. Get that fixed pronto because it can do damage to a lot of areas.
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BTW, never run the engine with the battery disconnected as the old timers used to do. It puts the system in danger the old systems could withstand.
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BG.

 

Thanks for the warning and ill check the sensor plug seating, maybe clean it to and keep monitoring. Glad thing to have engineering mode. Just what people need to monitor when they suspect a battery problem.

And to think, just yesterday it stayed 14.6 the whole time I drove.

For troubleshooting purposes, if this continues, I may unplug the sensor temporarily to see if the alternator puts out 14.6 continuously without the control of the BMS and go from there.

 

The drop in voltage you experience would be the Alternator field lead has been signaled to shut down the Alternator for some reason.
Maybe an open circuit or some other fault causing it io happen.
After all the Alternator is a variable output device intended soley to maintain the battery SOC and supply the whole system general power demands that constantly change ie A/C blower, headlights, fuel pump, fuel injectors, coils, and power this and that as needed.
The battery is there as a high current starting source, and backup power when the engine is not running plus as a filter to the >>AC Ripple<< coming from the Alternator in terms of variable frequency half wave pulses.