Multiple Warning Lights and DTCs

[Vinz Clortho]

Looking for possible causes. 2021 F150 Powerboost

Getting a lot of warning lights to include:

Stop Safely Now
BLIS
Service Soon Wrench
Check Engine Light
Park Aid Unavailable
Hill Start Unavailable
Pro Power Unavailable
Pedestrian Alert
Shifter Fault
Engine Coolant Over Temp
Motor Coolant Over Temp
Trailer Brake

DTCs regarding lost communication with various modules

Ford Pass message showing a fault in high voltage system

I brought it to 2 different Ford dealers, the first insisted it was an issue with the active air dam being broken and the second said the modules needed to be updated.

I've since removed the air dam and turned it off in Forscan as well as updated the software for the modules in FDRS but everything still comes up.

Anyone else deal with this or have an idea to the cause? Both dealers are pretty much refusing to look at the hybrid battery and/components. (Yes I understand it is a lot of work to do so)

Also, both 12V batteries are new and test fine.

Sponsored

 

[xtraman122]

How can a dealer refuse to look at any area of the truck? It’s what they’re literally there to do, that seems weird. Not like it’s some other brand vehicle.

 

[Vinz Clortho]

How can a dealer refuse to look at any area of the truck? It’s what they’re literally there to do, that seems weird. Not like it’s some other brand vehicle.

I know, it's very irritating. Especially when I have shown both of them the warning message specifically stating the high voltage system fault.

 

[Ricksc]

@Snakebitten you’re the powerboost king any ideas?

 

[Snakebitten]

Honestly, before I chased down any rabbit holes on something described like that?
I'd confirm both low voltage batteries had healthy resting voltage.

And in the process, disconnect both of those low voltage batteries for a while to allow the entire ensemble of modules to reboot fresh.

To measure resting voltage I would let the disconnected battery sit for at least a couple of hours and then put a voltmeter across each one. And I wouldn't be happy with either measuring less than 12.3 or better. A really healthy battery would rest much higher. 12.6-12.8

 

[Vinz Clortho]

Honestly, before I chased down any rabbit holes on something described like that?
I'd confirm both low voltage batteries had healthy resting voltage.

And in the process, disconnect both of those low voltage batteries for a while to allow the entire ensemble of modules to reboot fresh.

To measure resting voltage I would let the disconnected battery sit for at least a couple of hours and then put a voltmeter across each one. And I wouldn't be happy with either measuring less than 12.3 or better. A really healthy battery would rest much higher. 12.6-12.8

I've fully charged both batteries previously and still receive all of the alerts. I will try to disconnect them for a couple of hours then test them like you said. I'll hope it miraculously fixes everything but I won't hold my breath either. I'll report back with the readings.

 

[Snakebitten]

I wasn't aware that you were continuously experiencing the fireworks show. So when you charged them, were they still connected to the truck?

Just wondering if the truck already got a full reset.

 

[Vinz Clortho]

I wasn't aware that you were continuously experiencing the fireworks show. So when you charged them, were they still connected to the truck?

Just wondering if the truck already got a full reset.

The Aux battery was taken out of the truck to charge, the main was charged while sitting in the truck (but disconnected from all terminals). I just checked them now (connected) and they're both reading 12.3. These issues have been going on since June.

 

[Snakebitten]

OK, so more information..... Helpful

This wasn't a single incident.
It's been happening on occasions, but not until this summer, so things were fine for ~4 years.

Is there any consistency with each event? Always at startup? Or just randomly while driving around?

What do you have to do to successfully get where you are going?

 

[obert]

I take care of a fleet of Hybrid PIU Explorers and most of the time this happens they usually get a software update that cures the problem.

Most of the time a turn vehicle off and open door to reset everything will help but eventually they will end up in the shop. I just dropped one of this week and it is going to the dealer.

Very random and some don't ever do it. We have had some in service for years and then it will happen.

Sometimes it is a battery issue but that does not seem to be the case for you.

 

[Vinz Clortho]

OK, so more information..... Helpful

This wasn't a single incident.
It's been happening on occasions, but not until this summer, so things were fine for ~4 years.

Is there any consistency with each event? Always at startup? Or just randomly while driving around?

What do you have to do to successfully get where you are going?

Yes everything was great and no issues until then. The hill start alert happens when I brake and come to a full stop. All the other alerts start when I accelerate and continuously chime while driving around both city and highway. The AC will turn from normal operation to blowing warm air intermittently as well.

It has not started for me one time the other day after I parked and turned it off, then went to turn it back on and it would just enter the accessories mode, but then started no problem a couple hours later. To get where I need to go I need to continuously press the OK button on the steering wheel, but I try not to drive it much unless I have to until this issue is resolved.

 

[My 2ND Ford]

Looking for possible causes. 2021 F150 Powerboost

Getting a lot of warning lights to include:

Stop Safely Now
BLIS
Service Soon Wrench
Check Engine Light
Park Aid Unavailable
Hill Start Unavailable
Pro Power Unavailable
Pedestrian Alert
Shifter Fault
Engine Coolant Over Temp
Motor Coolant Over Temp
Trailer Brake

DTCs regarding lost communication with various modules

Ford Pass message showing a fault in high voltage system

I brought it to 2 different Ford dealers, the first insisted it was an issue with the active air dam being broken and the second said the modules needed to be updated.

I've since removed the air dam and turned it off in Forscan as well as updated the software for the modules in FDRS but everything still comes up.

Anyone else deal with this or have an idea to the cause? Both dealers are pretty much refusing to look at the hybrid battery and/components. (Yes I understand it is a lot of work to do so)

Also, both 12V batteries are new and test fine.

This may not be a software problem, since you mentioned loss of communication it may be something as simple as powers and grounds. The trick is finding out which circuits control the affected modules and start tracing wires, looking for bad connections at plugs and looking for bad grounds. For this you will have to get a wire diagram. I will be honest with you, this type of work is not something dealers are equipped or capable of doing. Every dealer tech is trained to diagnose software issues, people forget the basics. Without powers and grounds, nothing works. Good luck.

 

[Porpoise Hork]

Without knowing what DTC's were flagged, can only guess but this is what Perplexity identified based on your list of issues.


Low 12‑volt voltage or unstable ground: Ford’s service bulletin highlights that “Stop Safely Now,” “Check Engine,” and “Service Wrench” events can stem from voltage drops below 10 V at startup. These cause U‑code communication losses across control modules such as SOBDMC/BECM/ABS/PCM, and can cascade into multiple unavailable systems.

• Faulty auxiliary battery isolator (ML3Z‑14526‑B): A confirmed TSB (March 2023) details the isolator intermittently cutting power between the hybrid and auxiliary systems, causing DTC P2C44 and triggering numerous warning lamps. Ford’s fix is reprogramming the PCM and/or replacing the isolator.
  
• High Battery Junction Box (HVBJB) failure: Many owners report Ford replacing the HV battery junction box under warranty after “Stop Safely Now” and high‑voltage errors appeared with FordPass alerts. This box manages the HV circuit interlocks, and a fault interrupts high‑voltage communication and charging.
  
• Gateway Module A / network dropout: Later PowerBoosts have experienced U0293 or P1A43 codes in the BECM from gateway software faults that cut CAN communication. Ford issued SSM 52228 describing this, noting restarts may temporarily clear the issue.
  
• High‑Voltage battery or contactor fault: FordPass “High‑Voltage System Fault” messages and the truck’s shutdown behavior have been linked to a failing contactor inside the HV battery or internal sensor misreads, sometimes requiring battery replacement or recalibration.

I'd start by replacing the battery isolator. It's only about $65 and is connected to the positive terminal of the primary battery and can be replaced in a matter of minutes with basic hand tools.

 

[Beercity]

Had simular issue at the beginning of Sept, loss of connectivity to a bunch of modules.
Originally thought battery but did charging outside of vehicle and reset BMS.

Took to dealer and they said bad speed sensor after bricking ABS module. They were also doing axle recall and blamed the bolt on wiping out the speed sensor. Don't really think that was the case as the bolt wasn't sheared at the time.
They then ordered a wire harness that was on backorder. Took the truck at home due to previous issue where scratches on doors after leaving truck there for previous axle recall(before new design). I was told it was drivable other than ABS and other stuff not working.
After a couple weeks of not getting the part, I called the dealer and said the truck was down and I would be bring to them to sit until fixed. The brakes went to the floor when pressed before shifting into gear like a air bubble or low fluid when they were t-shooting the ABS issues.
The truck was parked away from other vehicles and brought in at night.
A few days later the harness magically came in and I got the call that it was ready.
Unfortunately I do not have the work order due to picking it up on a Saturday and the service guy wasn't in, so I can't tell you which harness was replaced.
Since then truck has been flawless.

 

[Bluegrass]

Looking for possible causes. 2021 F150 Powerboost

Getting a lot of warning lights to include:

Stop Safely Now
BLIS
Service Soon Wrench
Check Engine Light
Park Aid Unavailable
Hill Start Unavailable
Pro Power Unavailable
Pedestrian Alert
Shifter Fault
Engine Coolant Over Temp
Motor Coolant Over Temp
Trailer Brake

DTCs regarding lost communication with various modules

Ford Pass message showing a fault in high voltage system

I brought it to 2 different Ford dealers, the first insisted it was an issue with the active air dam being broken and the second said the modules needed to be updated.

I've since removed the air dam and turned it off in Forscan as well as updated the software for the modules in FDRS but everything still comes up.

Anyone else deal with this or have an idea to the cause? Both dealers are pretty much refusing to look at the hybrid battery and/components. (Yes I understand it is a lot of work to do so)

Also, both 12V batteries are new and test fine.

.
You must post DTC Codes with any attempt to ask for help.
The warnings you get are only an indication of issues supported by Codes to identify the root causes that has to be known, for help from a forum.
A lot of owners seem not to know this.
Good luck.

Sponsored