Stop Safely Now Warning

[thanhdaica1985]

I'm resurrecting this thread to report another SSN on my 2012 FFE. DTC code is P0A0A. This issue has been going on for 2 months now. Dealer has already replaced the harness, the PCM. Car always shut down coming to a stop as I remember. It happens very random so I don't know. The good thing is that this car is still under the extended warranty. The bad thing is that I have taken it into the shop so many times that I rarely drive it now.

[thanhdaica1985]

Has anyone had this issue with their cars? I believe that the SSN for my car will come on if I hit the accelerating pedal and release it too many times in a short interval. I have a feeling that the voltage fluctuation causes the interlock circuit to lock up. Anyone got any idea? Thanks.

[Heima]

I just did a quick google search on P0A0A. So generically, when there is an HVIL failure, this code is set.
HVIL is High Voltage Interlock Loop.
I made a post a couple of weeks ago about a poorly connected high voltage connector in my 2017. In that, I talked about 2-stage high voltage connectors.
Well, for the more important high voltage connectors, the second stage has an additional set of contacts, that sense when the connector is connected or disconnected.
This separate set of wires that do not carry high voltage, but run along the with the high voltage cables, form a loop through out the vehicle. The Wiring diagram shows this best.
Anyway, whenever a high voltage connector is disconnected, the loop opens up. This open is sensed, and the high voltage system shuts down.
So imagine that you have a crummy connection for the HVIL. The car will think that a connector is becoming loose, and will shut down the high voltage as a safety precaution.
I will describe the HVIL loop as I see it in the wiring diagram.



The first loop "starts" in the PCM powertrain control module. Connector C175B pin 59
It then goes to the BJB battery junction box. Connector C1035C pin 5
It then goes to the GFM2 generic function module 2. Connector C1838A pin 9
It then loops through GFM2 connector C1838C out pin 3 and in pin 4
It then loops through GFM2 connector C1838D out pin 3 and in pin 4
It then loops through GFM2 connector C1838E out pin 3 and in pin 4
It then leaves the GFM2 connector C1838A pin 7
It then goes to the BJB connector C1035C pin 13
it then goes to the TCM transmission control module. Connect C1822A pin 13
It then loops through TCM connector C1822B out pin 4 and in pin 3
It then leaves the TCM connector C1822G pin 1
It then goes to the DCDC DC to DC converter control module. Connector C1457A pin 4, where it "ends".
The second loop "starts" in the DCDC connector C1457A pin 3.
It then goes to the TCM connector C1822G pin 2
It then loops through TCM connector C1822E out pin 1 and in pin 2
It then loops through TCM connector C1822C out pin 1 and in pin 2
It then leaves the TCM connector C1822A pin 14
And finally goes to the PCM connector C175B pin 55, where it "ends"

So by looking at this diagram, it appears that if there is a break in the HVIL, it will either be reported by the PCM or the DCDC.
It also appears that there are 12 connectors where as HVIL is sensed. This is for a 2017, so for a 2016 and earlier, it would be fewer connectors.
The connectors are:
C175B - 12v logic connector
C1035C- 12V logic connector
C1838A -
C1838C
C1838D
C1838E
C1822A
C1822B
C1822C
C1822E
C1822G
C1457A

[Dobrinia]

On my FFE, I soldered a HVIL control circuit. Near PCM)

[thanhdaica1985]

So there are 12 different things that could go wrong and the same code will come up. What a design!

[Heima]

So there are 12 different things that could go wrong and the same code will come up. What a design!

Maybe, there might be slight differences in the codes, that would help identify where the problem is.
Nevertheless, it might be possible to do a continuity check of the loop at a few strategic points to determine where the open is.

[MermaidHair]

Add me to the list of SSN sufferers. I have a 2014 FFE with 45,000 on it. My car has been at the dealership since 7/5/19 and they still do not know what is wrong with it. Here are some relevant details:
- The wiring harness was replaced before I took delivery of the car back in 2014.
- I had one SSN incident in the first couple of weeks that was solved by reseating all of the connections.
- Next SSN error happened in April 2019. It was a one off and I thought nothing of it.
- I did experience the issue where my level 1 charge cord fried my home electrical outlet. Got a replacement cord but no assistance for the electrical repair at home from ford
- On 7/3/19 my teenage daughter was driving the car and started getting SSN errors. My phone was lighting up with texts from the car so I was able to tell her to stay off freeways and be aware. It happened 8 times over the course of about 10 miles of surface street driving. I had the car towed to the dealer (nearest one is about 20 miles freeway driving away) on 7/5
- At some point in the past month they offered us a loaner since it was taking so long. I thought this was because it was covered under the extended warranty. Not so sure about that now.
- On 8/1 we went to pick up the car. At that time they had 15 hours of labor on the car, replaced the charging ring, some other connectors and reprogrammed "9 out of 15 modules" in the car. All should be good and they will work with Ford to reduce the cost of my bill (you BET they will! 15 hours of labor is exorbitant. Tells me they don't know how to diagnose the car).
- Drove away. Daughter driving again. Got 4 miles from dealership and were going about 70 MPH on freeway when SSN pops up again. This time it was VERY DANGEROUS.
- Pulled over, restarted the car and took surface streets back to the dealer where the car is today. They are still diagnosing it. The tech wants to put in a new battery but Ford has not approved that yet.

Meanwhile, I am driving a brand new Fusion Hybrid (had 6 miles when they loaned it to me). This car is not to shabby but I want my car back.

[shniestEV]

Needless to say... passed warranty... they want to charge me $900 for diagnosing my car all this time.... said the error code indicates wiring harness. Wiring harness cost is $1700 plus installation so total bill will be almost $3000.

I asked if they did any of the standard troubleshooting like inspect all the connections etc before ruling that the ENTIRE cable is bad. Considering the vehicle can work fine for a month with no issues.

Told them to give me my car back and I'm not paying anything. I don't even trust driving the car anymore. as who knows where, when and how often its going to pop up.

But thinking that my dashcam had issues getting power to run and charge its internal battery maybe i do have a 12v battery issue and could that be the cause of an SSN error? I'm thinking of not paying any money to get my car fixed as per the dealers diagnostics and just trying a new 12v battery. I have since removed the dash cam altogether in case it to also caused some kind of system fault in the wiring.

An update to my issue. Long story short... it definitely was not a HV wiring issue and so glad i didn't pay $3000 to fix it. I complained to the dealership and to Ford Canada about their misdiagnoses and told them its crazy that their diagnoses would have led either myself or ford down an expensive path when i simply asked them to test the 12 volt system. Replaced the battery and reconnected the dashcam and everything has been perfect. Dashcam is working correctly and no more SSN in the few months since picking up the car.

I believe the cause of my SSN was the 12v battery getting to low to the point it was causing faults in the accessory circuits when the vehicle attempted to put additional load on it. Replacing that was a lot cheaper than anything ford suggested (even though i asked ford to check and or change it).

Ford canada followed up a few weeks ago and I let them know my frustration and the craziness of the dealership invoice they are trying to slip me. I have not heard back from the dealership since i left my complaint and picked up my car.

Anyways... car has been working great since...and my dashcam is charging and working normally.

[thanhdaica1985]

For my case, it wasn't because of the 12V battery that caused the SSN issue. I did replace the battery and it worked for a couple months. After that, and when the weather was hot I started getting SSN again. This time they replaced the PCM, harnesses. I got it back 2 weeks ago and it seems to work well now. I will update in the few weeks to see if SSN comes back.

[shniestEV]

Agree...it could be a bunch of different things that will throw that code. I had tested the 12v when i would get the error and it would label my battery as bad and to replace. What I also figured could have been a part of it was any 12v accessories I was using within the car adding additional drain. If you are using your car and dont have any additional accessories (dashcam, phones, etc) then its probably something else. If you do have anything connected regularly while driving (same items or more as above) I would also recommend as a test to swap out the cables you are using with better quality ones and or use a different USB port to test. This is how I diagnosed my issue and how I could determine the 12v tested good one day, bad the next, and then good again. There definitely was something (accessory or other) that was causing additional drain on my battery. So replaced the cables and battery and so far so good.