"Yellow Wrench" light while driving in the rain... later red warning!

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Well-known member
Jan 30, 2016
Problem: Yellow wrench came on while driving this morning in the rain, a powertrain fault. Got home fine (5 miles after yellow wrench), plugged it in. No drop in performance, nothing that I could tell was wrong, drove OK.

Then I went out and started it while it was still plugged in and immediately saw the dreaded "Stop Safely Now" with red triangle+! while on the driveway. Since its a red level warning, kinda serious maybe, I unplugged the car with about a half battery charge remaining.

Owner's Manual says:

Powertrain Fault (yellow wrench symbol)
"Lights when the system detects
a powertrain or high-voltage
charge system fault. If the
indicator stays on or continues to come on,
contact an authorized dealer as soon as
Stop Safely (red triangle with "!" inside)
"Indicates an electrical
component fault or failure that
causes your vehicle to shutdown
or enter into a limited operating mode. A
message may also display."

Background: 2016 Ford Focus Electric, almost problem free for 4 years and 32,000 miles so far.

Now I'm wondering if I should try to drive it 11 miles to the Ford dealership or call a tow truck (AAA) from my driveway. (???)

I'll read some other threads to see if its just the 12v battery or something simple. A 12v battery can go out at about 4 years. (Happened on my '15 C-Max at about that point.) ... Though, the Owner's Manual did say it may be the High Voltage charging system at fault when the Yellow Wrench comes on while driving. ... We could all learn something from this I guess.

I think the Ford dealership is operating just fine during the global pandemic.
Did your car get the recall fixed for that? (It may not be a recall but I know there is an issue there.)

There is a high-voltage wiring issue with the battery near the drivers side rear-wheel. Water can get in there and cause some corrosion in the connectors.

For the fix I believe they clean up that area, put new connectors on, and install a shield.

Call a dealer and ask--or if it is driveable take it there.
Since its a 2016 model, there was no recall for it, only earlier model years. Still, could be something like that. It was raining moderately hard when the yellow wrench appeared. A guess would be that water got somewhere in there. Sounds like that anyway. Maybe once it dries out I can take it in to the dealership, and hoping nothing got fried (over-amped) from shorts.
Calling the Ford dealership today to see if I can drop it by. As long as they are disinfecting and social-distancing in the shop, they should still be able to work on cars. They are selling & doing it all there now. Many places are closing or almost closing, but many can just function with precautions.

Should be covered under the 8-year "electric components" warranty:

"Under your New Vehicle Limited Warranty, the following Focus Electric components are covered against defects in factory-supplied material or workmanship for 8 years or 100,000 miles (whichever occurs first) from the original warranty start date: High-voltage battery packs, high-voltage charger, DC/DC converter, Electric Drive Module Assembly (includes electric motor and gear box), trans range and charge cord."


Few of us will reach the 100,000 mile mark in 8 years since these fun sports car toys only get a reliable 60 miles (with margin) per day or per charge, especially if using it on the highway with that extra aero drag and/or cold weather heater usage!
OK, I did find tech bulletin 16B02 which does indeed cover my model year (2016 and earlier models) and build date too.
However, Ford was doing this "customer satisfaction" program only in certain states, and not in my Colorado, which would explain why I was never contacted about it.
(Maybe the state attorney generals in those affected states were more agressive? Don't know why some states are excluded. We get rain & snow here too.)...


Build Dates: September 15, 2011 through December 9, 2015
Colorado and California were excluded from this thing that ended May 2017 anyway, so this is just info, not a recall.
Could be useful to tell the local Ford technicians & service advisor about it so they have a clue.

Customer Satisfaction - 16B02 – High Voltage Lower Battery Connector Corrosion – 2012-2016 Ford Focus Electric

Certain 2012-2016 Model Year Focus Electric Vehicles
High Voltage Lower Battery Connector Corrosion

In the affected vehicles, corrosion on the high voltage lower battery connector may cause deformation of the connector allowing water ingress. Water ingress into the high voltage lower battery could result in a high voltage circuit isolation fault with a “Stop Safely Now” message displayed in the message center. If this occurs, the vehicle may not restart once it has been shut off.

Before delivering any of the vehicles involved in this program, dealers are to remove the high voltage lower battery from the vehicle, clean and inspect the high voltage lower battery connector, apply corrosion protection, install a protective shield and reinstall the high voltage lower battery in the vehicle. This service must be performed on all affected vehicles at no charge to the vehicle owner. NOTE: The high voltage lower battery in some vehicles may require shipment to a specialized facility to complete repairs.

Due to capacity constraints to repair the high voltage lower battery, and to assist dealers in managing customer expectations, owners of affected vehicles will be notified in four separate mailings. Mailing will begin by March 28, 2016. Dealers should repair any affected vehicles that arrive at their dealerships, whether or not the customer has received a letter.
In January of this year, a new Technical Service Bulletin (TSB) 20-2004 came out which blamed an internal battery coolant leak for it, though I think it's probably the above 16B02 rain problem, I'm guessing: TSB 20-2004 https://static.nhtsa.gov/odi/tsbs/2020/MC-10170911-0001.pdf 

Since the yellow wrench and red "stop safely now" happened during & after driving when raining outside, the Field Service Action (FSA) 16B02 might just be the one that applies here:  https://static.nhtsa.gov/odi/tsbs/2016/MC-10074364-0699.pdf  

I'm going in Monday to the dealership and will make sure the Service Advisor gets the "nudge" toward 16B02 and 20-2004. They should know already when they do a search, but I've sometimes had problems over the last 40 years of doing this just to get them to take the time to research the issues in Ford's (and other maker's) databases. Sometimes you have to hold thier hand or face long wait times and/or miss out on warranty coverage.
For example, I read something where a dealership idiot Service Advisor told a customer the rain-induced 16B02 problem was really for their car insurance to handle!!! Unbelievable. It should be paid for by the 8 year warranty we have.
16B02 expired in 2017 so they will do nothing. Further the wiring harnesses aren't covered by the warranty so you are SOL there too. Luckily (TSB) 20-2004 looks like it also covers the same as 16B02 so you should be golden.
My guess is water ingress and corrosion to the battery connector.

Good luck and let us know how things go.
Seems that TSB 20-2004 is pretty much for all FFE. This is the summary at https://www.nhtsa.gov/vehicle/2018/FORD/FOCUS%2520BEV/5%2520HB/FWD#manufacturerCommunications:


NHTSA ID Number: 10170911

Manufacturer Communication Number: TSB 20-2004


Some 2012-2018 Focus Electric vehicles may exhibit a Stop Safely Now message displayed in the instrument panel cluster (IPC) message center. This may be due to either an internal coolant leak on the upper or lower high voltage battery or corrosion on the lower high voltage battery connector caused by water ingress. If this occurs, the vehicle may not restart once it has been shut off. To resolve the condition, follow the Service Procedure to replace the upper and lower high voltage battery or apply corrosive protection.
7 Affected Products
1 Associated Document
Request Research (Services fees apply)

But the TSB itself does not include 2017 or 2018 model year vehicles. The fact that the bulletin is available to 2018 FFE (See the main heading of the NHTSA page) contradicts the exclusion in the bulletin text. So the only way I can think of knowing for certain if a 2017 or 2018 is covered by this issue, is to see if the bulletin is listed in Oasis for the vehicle. Does anyone have access to Oasis?

As for payment, it is stated that it is covered by the New Vehicle Limited Warranty.
For Canada:
Under your New Vehicle Limited Warranty, the following Focus Electric components are covered against defects in factory-supplied material or workmanship for 8 years or 160,000 km (whichever occurs first) from the original warranty start date: High-voltage battery packs, high-voltage charger, DC/DC converter, Electric Drive Module Assembly (includes electric motor and gear box), trans range and charge cord

For USA:
New Vehicle Limited Warranty. We want your Ford Focus Electric ownership experience to be the best it can be. Under this warranty, your new vehicle comes with 3-year/36,000-mile bumper-to-bumper coverage, 5-year/60,000-mile Powertrain Warranty coverage, 5-year/60,000-mile safety restraint coverage, and 5-year/unlimited-mile corrosion (perforation) coverage – all with no deductible. Please ask your Ford Dealer for a copy of this limited warranty.
Electric Component Warranty. Your vehicle’s unique electric components are covered during the Electric Unique Component Coverage, which lasts for 8 years or 100,000 miles, whichever occurs first. Please refer to your Warranty Guide for coverage details.

So that might be problematic. Logically, the problem is with the battery, so the battery warranty should cover this. Checking the warranty guide there is a diagram showing the Hybrid/Electric Unique Component Coverage - 8/100000 is under the blanket of "Your New Vehicle Limited Warranty".


There is also this text, with my highlights:
(4)Your vehicle’s unique hybrid / electric components are covered during the Hybrid / Electric Unique Component Coverage, which lasts for eight years or 100,000 miles, whichever occurs first.
•The following hybrid parts are covered during this extended coverage period: high-voltage battery, hybrid continuously variable transmission,Inverter System Controller (ISC), DC/DC converter, high-voltage battery connector, battery pack fan assembly, thermistor probe, Hybrid Battery Pack Sensor Module (HBPSM), Battery Energy Control Module(BECM), and the PHEV onboard charger.
•The following plug-in-vehicle unique parts (if equipped) are covered during this extended coverage period: high-voltage battery packs,high-voltage charger, DC/DC convertor, electronic drive module assembly (includes electric motor and gearbox), transmission range sensor, and charge cord.

Hmmm, the connector is covered for the hybrid, not the bev, and the charging cord is covered for the bev and the not the plugin hybrids. Perhaps the ambiguities are what made this repair take weeks on end.

In this type of situation, it is best to get in touch with Ford, not the dealer, and determine if they will pay for the repair. However, contact Service Engineering Operations, not customer service. Michael Berardi was the director of this division, don't know if he still is. Yep, from Linked In it looks like he still is.

As a tip from an insider. Squeaky wheels get greased.
Nice! Lots of insider and experienced info above.

Heima's points on whether or not the connectors (or their cracked mounts!) are included is interesting. It could depend on whether that's automatically considered part of the battery pack or not. I could see it going either way. Weird stuff.
And I see the TSB 20-2004 does indeed include the rain water ingress problem (like 16B02) in addition to the possibility that internal coolant ruined something inside the big fat high-voltage battery back there, a 640 lb monster which keeps us glued to the road. :D

As we Focus Electric owners see some time and mileage on these things, we may have to visit the dealership more and more.
I just want 10 years out of this thing, and then I'll do a Thelma & Louise off a cliff (minus me or Thelma in it!), but not now at the 4-year point.

I just took it in to the dealership. I mentioned 16B02 and the perhaps more recent & relevant TSB 20-2004 to the Service Advisor who looked like he just graduated 8th grade. .... Most Ford technicians have a lot of experience with hybrids around here at least!

Focus electrics r very rare in Colorado. Wish I could take it up to Boulder, CO, where there are far more sales of electric cars, as that's a green hippie town, seriously high numbers of Nissan Leafs, etc. sold, along with some Focus Electrics too up there.

Maybe Ford should treat us well on warranty issue 'cuz they want us to buy the new Mustang EV 8 months from now, right?!
Or are there enough of us old Focus Electric buyers out there? We'd get almost nothing for a trade on a new Mustang EV, you can bet on that, sadly! :(
So much for brand loyalty.

Since those connectors are part of the battery itself, (if you bought a new battery, they would be right there on the battery), it should be covered under the battery warranty. The high voltage cables that connect to the battery however, are a different matter. Yet it seems that the bulletin is not for the electrical connection per se, but rather that water is leaking in behind the connector, and the feeler gauge is used to determine the gap behind the connectors. Water/coolant in the battery will cause isolation faults, and that will bring on the yellow wrench and the SSN message.
Read some more of the huge thread "Stop Safely Now Warning" thread in this Technical Discussions section and its not real encouraging. What MermaidHair, tinilk, thanhdaica1985, etc., etc. had happen is just crazy.

Maybe Ford will "promise" that the upcoming Mustang EV will be better, and we should start trusting them. I do wonder how much the Mustang EV will benefit from the Focus (Magna) system's lessons. I think Ford is trying to bring EV engineering more in-house instead of really just buying all the big parts from Magna like ours.

I would say "don't buy Fords" because of this stuff, along with how they sca-rewed thousands of customers over the Ford Focus & Festiva automatic transmission issues for about 8 years running!! However, other car makers have spotty records too in paying for repairs and replacements when bad designs creep in to their product lines. Lots of examples from GM, Hyundai, Nissan, .... the list goes on, they all have issues they try to dodge (no pun intended, but some friends of mine with a Dodge say it really means "dodge warranty issues and responsibility").
Service Advisor calls me every day. Today, they finally got a chance to look at it in depth (2 day delay, not bad I guess). They say its some kind of identifiable part that acts like a fuse between the battery and electronics. I might know more later on what exactly he is talking about.

He says its covered under the 8-year warranty.
No loaner car available.

He ordered the part, and they might have the car ready by Friday if we're lucky.

Nice they have people working during the Zombie Apocalypse. They only have to pause work once in a while to fight off the zombies (sorry, I just saw "Zombieland II" recently) and it's not a line item on the shop charges, I hope.... ...When I get the car back, I'll take the unusual step of wiping down the car with alcohol!
Some electric vehicles have a pyrotechnic disconnect fuse, pyrofuse, or pyroswitch. Thats a fancy way of saying fuse with an explosive charge. The fuse is a fast acting type and might detonate/fire when the airbags are deployed or if HVIL opens under load. If that device activates, power from the HV battery is cut, and your vehicle is effectively dead in the water.

Some people might consider a contactor like a fuse, because they have finite lives and if the precharge contactor fails, you could have a weld/stuck contactor. Kind of the opposite of a fuse.

Some vehicles have E-fuses, or electronic fuses. These are circuits that replace the simple wire strand type fuses. They can respond faster, report to the computer, and reset themselves or by command of the computer.

If there is water in the battery, and upon the first short from the water (this would be fast because the water would vaporize), the computer would sense the transient change in battery voltage and supplied current, this would set a condition to shut down the vehicle as soon as it came to a stop.
Heima, true the fuse the service advisor (Jack) spoke of might just be an effect from the real cause of an over-current, which is water ingress, since it all happened during rain.
To find out if water was indeed the underlying problem, I plan on calling Jack today to see if the technician inspected the battery for connector integrity and coolant leak evidence per TSB 20-2004 when he did diagnostics. By faulting the HV "fuse" or circuit breaker, it could be the technician is being overly lazy about fixing the real issue that caused the over-current in the first place.

I've noticed over the years that technicians and service advisors are very careful about what they do for warranty work since Ford can reject what they decide to do, and they get in trouble with everybody, including the dealership management, Ford, and the customer who gets a big bill if they do too much. So they tend to be too minimal in their approach. Dealership owners don't like warranty work that much because they get paid lower labor rates from Ford for it too.

And I might try to get them to put on the new plastic splash shield design modification and anti-corrosion spray to prevent any future water ingress, per FSA 16B02, and later included as part of TSB 20-2004.
Got the car back. They replaced part number CM5Z-10A757-A which is the "Drive Motor Battery Pack Disconnect Switch, Disable Switch, Switch Assembly" and the car runs OK now. Guess that was it! It's a $140 part, and they would probably charge a person $500 total if warranty didn't cover it. It was covered under the 8-year battery system warranty fortunately.


It is #3 in the image, a switch used to disconnect the High Voltage battery system. Weird it would just fail to open like that.

I got a lot of shoulder shrugs (we don't care, go away, don't ask us that, kinds of body language) from both the service advisor and the technician himself when I asked them both if they thought I should proactively do the TSB 20-2004 with it's CM5Z-9916A315-A High Voltage Lower Battery Connector Shield and spraying the big connector with Daubert Nox-Rust 7703-W (waxy, gooey sealant to keep water out). I may try to do it myself since it looks kinda easy actually, rather than paying those labor rates. ... The Ford company would prob tell me to go eff myself if I asked them, but I might try anyway to get them to pay for it like they did in FSA 16B02 a couple of years ago.

The paperwork on it says:
(PPT is Pinpoint Test, and BECM is Battery Energy Control Module computer)
"30321 Verified Concern.
Codes P0AA01, in PCM (powertrain control module computer).
Performed PPT E1 No E5 Yes Test BECM code P0A0A00 Performed PPT A1 Yes A2 Yes A5 Yes A6 Yes A7 Yes. Vehicle still won't start and has the same code. Performed PPT A again with the same results. Still won't start.
Bench-tested the CM5Z-10A757-A Disconnect Switch and it was found to be open (failed). Replaced Disconnect Switch with new one and now car starts OK. Cleared codes and retests good. Measured time for abnormal diagnostics and replacement of the switch is 2.2 hours labor.
jmueller065 said:
There is a high-voltage wiring issue with the battery near the drivers side rear-wheel. Water can get in there and cause some corrosion in the connectors.
Wow, I just took a picture of that. Awful they put the connectors so close to the tire back there!

Now I see why Ford put out 16B02 and installed the complex shaped CM5Z-9916A315-A High Voltage Lower Battery Connector Shield in lucky states. ...
The high voltage connector is exposed to water, slush, gravel, rocks...... Was this designed by monkeys? A simple shield could prevent a lot of problems. At least its easy to get to to install a shield. I noticed its $123 bucks.
That disconnect has a 350 amp fuse in it, and you blew it? Ok, fess up, you were doing burnouts, right?
When that disconnect opens you have no HV battery power. Given your situation, and the behavior of the vehicle, does that make sense?
Without the HV battery, you could not have driven anywhere. Everything was being powered off of the 12V battery.
You might want to check the health of your 12V battery because yours might have gotten deeply discharged.

Still, I hope this truly solves your problem, and you are not bothered with those nasty yellow wrenches every again.
Heima, Did you find out there is a 350 amp fuse inside the switch from a Workshop Manual?

Per my 1st post, the yellow warning came on while driving. I continued several miles to home OK, & the car continued under full power.
(( Only the HV battery can power the main electric motor. The 12v system can't provide motive power. ))

After it was on the driveway a few seconds it would not start & had a SSN 'stop safely now' red warning.

It was raining at the time all this happened. I think water got inside the connectors while driving. Then water shifted or coalesced and fried the switch while stopped on the driveway. After drying out for days and getting a new switch/fuse, it now functions OK. Until it rains again that is.
Given the splash shield is only around $123 or so and easy to install (TSB 20-2004 shows it is), I'll just order the dang part and complain to the dealership that they gave me a band-aid solution without helping me with the real underlying root problem: Water ingress causing amp surges.

Heima said:
That disconnect has a 350 amp fuse in it, and you blew it?
A 350 amps fuse threshold makes sense here, so you did likely get that number from the official Workshop Manual as suspected. ...... 107,000 watts / 318 volts = 336 amps at full power, which is a normal amount since most of us drive with our foot to the floor sometimes when you only have 143 hp (107 kW) available to push 4,000 lbs around.

That explains why those copper power cables have to look like they could support the Golden Gate bridge and run thick insulation too.
I just pulled the disconnect from the back seat of my focus and took this picture:


As you can see 350 Amps, 690 Volts. The one at the right rear tire is probably the same.

The plates to the left and right are the connection for the high voltage. The pins at the top and bottom could be either HVIL, or a shunt.
I am thinking that is where your problem was, in the top and bottom pins.

I stand corrected, they are neither. There is no resistance between them. So perhaps should the fuse blow, a circuit inside will close, and the two points become common.

You can buy the fuse core from:
For $141
However, the part is embossed with the words "ASSEMBLY IS NOT SERVICEABLE"
So it probably would be fairly difficult to disassemble or is a destructive endeavor.