Search the Community

I have a 2012 MKZ Hybrid, and starting about 4 or 5 months ago, my MPG started to decrease dramatically. I bought the car 4 years ago, and I've been consistently getting over 33 MPG, it's now down to 26 MPG. The HBV is fully charged, but the electric drive is rarely engaged anymore. As soon as I turn the car on, the engine starts. The car is in great shape, and I don't want to get rid of it. Has anyone experienced this? Has any heard about Lincoln building a time limit on their HVBs? I saw a posting on the Ford Fusion Hybrid forum that indicates that the Hybrid EV drive is limited to 8/9/10 years based on expected HVB lifespan. Has anyone tried the procedure discussed in this post on the Ford Fusion Hybrid forum? https://www.fordfusionforum.com/index.php?app=forums&module=forums&controller=topic&id=19361&tab=comments#comment-109237

New forum member. Bought a 2014 MKZ Hybrid in Nov 2019 with 94.5K miles, now has 104.5K miles. Three weeks ago the 12volt battery died. Luckily the car was unlocked. Popped the hood and tested the voltage at the jump starting bolts and it read 2.5 volts (yes, two point five volts). Trunk would not open with buttons or fobs, so put down the back seats, crawled back a bit into trunk and pulled the emergency release. Voltage at the 12volt in the trunk was 2.5 volts. Bought the new specified 12volt Motorcraft battery at the Ford dealer and installed that in trunk. Car now started and ran fine, but trunk would not fully close, nor open automatically. Bought the new Rear Gate Trunk Module (RGTM) from a Ford dealer and installed that ( online videos have been very helpful with this process!). Trunk now locks and cinches down, and unlocks. The RGTM should be reprogrammed with updated codes, but dealer would not do this as I installed module myself. That's OK, I can live with some reduced functionality, but I still had a problem with finding parasitic electric draws. Car 12volt battery was not charging properly, battery voltage would drop overnight to low 12 range. Did a lot of web searching and reading, including in this forum and the Ford Fusion Hybrid forum. I have 3 different OBD2 readers (cheap, Autel MK808, and Forscan). I have used all three to check and turn off DTC codes, and see into as many relevant systems as I could. I have used Forscan to turn off as many nonessential electric draws as I could, to test/set a new battery "type", and to test/observe results with BMS on and BMS off. One observation I have from this project is that the 12volt battery can and does get charged from the HVB. One way to see this is to pop open the hood and check the voltage (with multimeter) with car totally off, then turn on the car BUT don't start it (push the start button without your foot on the brake). With car totally "off" I had readings of 12.2+ volts, but with KOEO (key on engine off) I had readings 14.2+ volts. (Some of the cars many systems start drawing electricity when you open the car door, and it takes a while - minutes - for them to go back to sleep after your shut the car door.) This makes sense to me. The gas engine can power the car and charge the HVB. The HVB is getting about 300+ volts from the engine's generator. The HVB assembly includes a DC to DC inverter that steps down the HVB voltage to the 14+ range for the 12 volt battery. This is what I think is going on, in very simplified terms. At present, with the reduction in interior lights and other nonessential draws, and with BMS off, I finally had the 12volt battery up to 12.8 volts after a long afternoon drive yesterday and it settled down to 12.6 volts overnight - which is right where I want it to be. Matt