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Ford 1.0 EcoBoost Hybrid (mHEV 48 V) engine: reliability and faults

Petrol · 999 cm³ · 125, 155 hp · since 2019

Good choice, check first
Reliability
5.0/5

1 known fault

Verdict

A three-cylinder turbo petrol engine of 999 cm³ combined with an 11.5 kW integrated starter-generator and a 48 V battery, in 125 or 155 hp, introduced on the Puma and then offered on the Fiesta and Focus. It has no fully electric mode. Several recalls have concerned the fixing of the 48 V battery cables and terminals (risk of local overheating, or even fire): check that they have been carried out. The timing system is debated: some sources state that mHEV versions have a chain (the oil pump still driven by a belt running in oil), while a parts supplier lists the 2019 Puma among the 1.0 EcoBoost engines with a wet belt. Have the engine checked by serial number (VIN) at Ford.

Years to favour or avoid

To favour
No year particularly to favour
To avoid
No year to avoid identified

Known faults

48 V battery cables and terminals not properly secured (recalls)

Manufacturer recall

Several recalls have concerned the 48 V mild-hybrid circuit. On the Focus, campaign 21S01 (vehicles built from 25 June to 30 November 2020) targets a battery terminal nut that is insufficiently tightened, and campaign 21S36 (vehicles assembled from 13 August 2020 to 19 January 2021) a 48 V battery earth cable that is improperly fixed; in both cases the fault can cause local overheating, or even a fire. The Puma mHEV was the subject of a similar recall for the tightening torque of the battery connections (vehicles built from November 2019 to July 2020). The work is free of charge at Ford: check that it has been carried out.

Fixed free of charge by a dealer and not counted in the reliability score: ask for proof the work was done (invoice, or a VIN check at a dealer).

Versions
ecoboost-1-0-mhev
Onset
not documented
Repair
not documented

Models fitted

  • Buy with care

    Photo: Herranderssvensson, CC BY-SA 3.0

    Ford Fiesta

    2017–2023 · Petrol, Diesel

    Estimated monthly cost
    €345/month
    See the guide : Ford Fiesta
  • Good choice, check first

    Photo: Vauxford, CC BY-SA 4.0

    Ford Focus

    2018–2025 · Petrol, Diesel

    Estimated monthly cost
    €398/month
    See the guide : Ford Focus
  • Good choice, check first

    Photo: Cutlass, CC0

    Ford Puma

    since 2019 · Petrol, Electric

    Estimated monthly cost
    €439/month
    See the guide : Ford Puma

Maintain and diagnose this engine

Read fault codes

An OBD scanner plugged in under the steering wheel shows stored fault codes, even with warning lights off: useful during the test drive.

Parts and maintenance

Compare prices of car parts (timing, brakes, filters) to estimate the repairs to plan for.