Keeping it simple
Good morning all, I recently shared this Case Study with a Facebook group, I hope you all enjoy. I wanted to touch a few bases throughout this write up. First and foremost keep it simple, read service information, look up wiring diagrams & lastly don't rely on just one piece of test equipment.
I had a 13 Ford Fusion Hybrid in my bay Wednesday for a dead battery complaint. Battery was previously charged, I tested it with a midtronics, it passed. I let the vehicle run for a while, while I kept busy with other things. Battery light comes on followed by a message saying check charging system.
Pull codes, found 55 codes stored throughout the 25 systems scanned. I can't figure out how to attach shop stream report (My apologies) I added a few pictures of codes I decided to focus on. Looked at live data in the Battery energy control module, nothing useful in the Snap On, looked at it with the Autel and I found fan speed desired vs actual. Found it being commanded on but nothing happening.
Long story short, found a missing power feed to the Hybrid Cooling Fan Motor. Caused by an aftermarket tap-a-fuse at the Junction Box. I removed the aftermarket wiring, installed a new fuse in its original location (Checked pin fitment). All is well. Thank you for reading, & thank you Scott Brown for reaching out.
Was this the hybrid battery going dead?
I believe the Hybrid battery would overheat due to the fan not working and shut all the systems down. Such as the DC to DC converter. Once the battery would cool down, the DC to DC converter would start working again. & you would get regular charging voltage of 14volts. At leas that’s my understanding of the system. Hope I answered your question.
Yes, you did. I just wanted to be sure. Thanks!
Nice find Angel! Did you notice when the car would act up did it start "voltage shedding" any of the systems? (ie did it shut down the air conditioning or infotainment?) I'd also imagine if the hybrid battery got hot enough the car would go into reduced power mode and illuminate a hybrid system warning message. Does the city of Boston have a lot of hybrids in the fleet? I'm about 30 miles north…
Thank You Matthew, I read an article about your shop by Mass Vehicle Check, and It's stuck with me since reading it. Great operation and very inspiring. Unfortunately I can't say for a fact that it did go into a load shedding strategy. We do have quite a few hybrids, propane and electric vehicles in our fleet. While researching some of the codes I read in service information that the red…
Thanks for the kind words. Are you seeing a lot of transmission failures on the Fusion Hybrids or C-Maxs? (Same transmission) I have a 13 Fusion in the shop now that had a catastrophic bearing failure, I believe one the final drive bearings which there's a TSB for. When I ordered the reman from Ford they said it was on back order.
Surprisingly haven't had any of the hybrids needing transmissions as of yet. Econoline's and F350's now that's a different story. I will keep an eye out if we do and keep you posted.
Awsome thanks! If you ever have any fun hybrid issue here's my email: … I'm always interested and happy to help.