LET ME START WITH, I DO NOT THINK THIS IS A MAJOR ISSUE.

It all started with a little ice...

Two weeks ago I came home late, after midnight... and I had 8" of snow and ice on my upwards sloped driveway. Who wants to shovel / snowblow at midnight, right? So I really had to gunn it in the street and get some speed and momentum up to attack the uphill driveway. ( plus I have FWD ) So going up the drive, as expected, the tires were spinning and slipping to a pretty large degree, but I kept moving. When I got near the garage, I had to hit the brakes. As expected ABS brakes, and the flashing light came on, and ABS ( at slow speeds anyhow ) always puts my car into EV, and that happend this time also. ( The car will go EV with A/C or defrost on too, in the red setting, if ABS happens.)

Okay... wheel spin accelerating uphill on snow, expected, and no prob.
A little ABS skid at the end when braking, expected, and no prob.
I parked the car for the night.

Next day, right from the first key turn: "SERVICE REGEN SYSTEM"
And while I could drive just fine, all regen braking was disabled.
The battery still charged via ICE, and I could still drive EV.
Two more key cycles, then the message went away and stayed off.
Regen was back on.

I took the car to the dealer yesterday for the HV battery wire harness.
While it was there I mentioned the "SERVICE REGEN SYSTEM" and asked them to check it out. The car had stored 6 DTC codes.

P1A03 - Traction Motor Shutdown - "This DTC is set when the PCM requests traction motor shutdown though a CAN signal, or if there is a motor shutdown circuit fault.*" *Possible cause, a problem with signal wires or grounds in the CTO ( clean tach out ) GSDN, MSDN, TMAC ( torque of motor AC signal ), TGAC ( torque of generator AC signal ).

P1A04 - Generator Shutdown - ( same basic message )

U0100 - TCM or TBCM lost communication with ECM / PCM, or did not recieve messages within the defined amount of time.

U0111 - PCM or TCM lost communication with the TBCM, or did not recieve messages within the defined amount of time.

U1900 - my mechanic wrote this down, but it's not listed in my manual.
U2023 - my mechanic wrote this down, but it's not listed in my manual.
* Help on those last two would be appreciated!

DTC = Diagnostic Trouble Code
TCM = Transaxle Control Module
ECM = Engine Control Module
PCM = Powertrain Control Module
TBCM = Traction Battery Control Module

I think I got those names right... doing this from memory...
Anyone know what kinds of code the ScanGauge is supposed to display?
It DOES NOT display any of these DTC's.

After the mechanic called Ford tech support, tech said a likely cause for the P1A03 / P1A04 was a bad ground in G103, G300, or G301.
The mechanic checked all 3 ground wires, and cleared the codes.
He then did the wire harness recall work on the battery.
My dealer is using the word "recall" on my invoice.
I thought it was a "customer satisfaction upgrade"?
On the invoice it says "light recall - recall 04B48".
But maybe the hybrid is so unique, that was the closest descriptor from a pick list in the computer or something. "Installed jumper wire, reprogramed BCM."

Just thought some of you would find that interesting.
What's your vote on the codes?
Was there a problem somewhere?
Or was it my Ice Capades that was the root cause?
-John

I wonder...

Regenerative braking is INSTANTLY disabled when/if ABS activates during actual (hydraulic) braking. I wonder if maybe it isn't subsequently re-enabled unless there is a follow on forward motion via throttle opening. Assuming you shut the ignition off immediately after ABS's activation it may have remained "off' until the restart the next morning.

The kind/type, not readily foreseeable, of firmware bug that can be easily over-looked.

Look at:

U0100, U0111

A "quick" ignition shutdown might prevent the follow-on "regen" re-enable "message". Or the "re-enable" of regen was/is a function of forward motion under power subsequent to an ABS disable.

If regen were to be disabled due to ABS activity I certainly would not want it to be re-enabled, say during a follow-on coastdown, non-braking coastdown, to a full stop.

U1900 - CAN Communication Bus Fault - Receive Error
U2023 - External Node Fault DTC

U1900, U2023 are communication codes. they appear when there is module to module communication error, in this case the ABS system. there is no reason to be concerned with these codes. they happended becasue of the other codes.

The P1A03 and P1A04 are the result of something else going wrong. Sounds like you had a communication error that caused the shutdown, most likely multiple events dealing with your "driveway event". Alot of DTCs take 2 key cycles or 2 warmup cycles to reset. I have this reset problem from time to time when I disconect my scan tool from my FEH and dont follow the exact procedure for shut down.

Ducit Amour Hybridae
Mark Smith
Master Certifited Technician
Tempus non reparabilis fugit
"It isn't pollution that's harming the environment. It's the impurities in our air and water that are doing it."

Best Tank 35.0 MPG

Thanks Bethany! Either you are super smart or you have a S.O. who works for Ford perhaps? ( or both!) I figured it was very minor. All codes have been cleared and the car runs great. I was just curious about the last two. From the category, I figured they were in the communications, rather than mechanical error category. Thanks for the details! -John