Why does my Fusion Hybrid use the electric motor less and get worse mileage?

Short answer: If a 2010-2012 Fusion Hybrid uses the electric motor less every month and mileage keeps dropping, the high-voltage battery and how the car rates its age are the likely cause. Owners report a dealer reset of that setting brought electric driving back, while a new battery was quoted around $7,000. Before that, rule out winter, tires and tire pressure.

Symptom: The car rarely runs on electric power, even downhill or at low speed, and mpg has fallen several points.

What to check first

1. Compare mileage across seasons. Winter drops are normal.
2. Check tire pressure and whether the tires were changed.
3. Ask a Ford dealer to scan the hybrid system and check the battery's health and age setting.
4. Ask whether any software updates or bulletins apply to your VIN.
5. Get a battery quote from a hybrid battery shop as well as the dealer.

Likely causes

1. Aging high-voltage battery or battery-age setting. Owners report Ford's system limits how much battery power it uses as the battery ages. A dealer reset of that setting brought electric driving back for one owner. A worn-out battery can also do it.
2. Cold weather. Hybrids get worse mileage in winter. The engine runs more to heat the cabin and the battery works less well cold.
3. Tires, pressure and maintenance. Different tires or low pressure cost mileage on any car, especially a hybrid.
4. Other hybrid faults. Codes from the hybrid system need a Ford-capable scan.

What it usually costs

One owner said Ford quoted about $7,000 for a new high-voltage battery, and aftermarket batteries they found were about $2,500. Owners didn't post prices for the dealer reset.

Is it safe to keep driving?

Lower electric use mostly costs gas money. If a warning message comes on or the car loses power, get it checked before long trips.

DIY or shop?

Tire pressure and tire choice are DIY. Battery tests, resets and replacement are dealer or hybrid-shop work. A hybrid's high-voltage system can stay live even with the car off. Leave the orange cables and the big battery to a hybrid-trained shop.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA's recall lookup returned no recalls under the separate name 'Fusion Hybrid'. Under 'Fusion' it lists 10V222000 (some 2010 cars: a park rod guide pin may not be installed right) and 15V340000 (electric power steering), neither about battery power. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• Plain words: The complaint count below shows how often owners reported problems that mention these words to NHTSA. NHTSA's complaint lookup doesn't separate the hybrid from the regular model, so this count covers the whole model line. A count is not proof of a defect.
• NHTSA complaints: 1783 keyword-matched complaints for Ford Fusion Hybrid / Fusion (NHTSA lookup) 2010–2012 (of 6224 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-30; keywords: hybrid, high voltage, mpg, mileage, electric mode) (NHTSA returned no data for 9 model-year queries). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In 2010 Ford Fusion Hybrid electrical motor comes on less; mileage dropped on Car Talk, a 2010 Fusion Hybrid with 44,000 miles started using the electric motor less and less until it almost never came on. A Mercury Milan Hybrid owner said a Ford mechanic told them the high-voltage system limits battery power as the battery ages, and that it could be reset. The Fusion owner later reported the dealer reset it per Ford's instructions. The Milan owner said Ford quoted about $7,000 for a new battery.
• In 2010 Mercury Milan Hybrid - MPG going down on Car Talk, a 2010 Mercury Milan Hybrid (the Fusion's twin) slowly dropped from 38-39 mpg to 32-33 even after new plugs and an air filter. Members asked about tire changes, seasons and driving patterns.
• In Fusion Hybrid 2013 - Getting only 20 MPG after Service on Car Talk, a 2013 Fusion Hybrid owner (the next generation) said mileage fell from about 40 to about 20 mpg after a dealer service, and the dealer couldn't explain it. It shows how a drop right after service is worth taking back to the dealer.

Quick tip

Ask the dealer specifically about the battery health and age setting. Owners got their electric driving back that way without buying a $7,000 battery.

Vehicle focus: Ford Fusion Hybrid and Mercury Milan Hybrid, 2010-2012 (a 2013 thread is included for comparison).

Safety / mechanic note

High-voltage parts are a safety item. Verify with a mechanic.