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M1JCM1JJM1JU

1.0 EcoBoost 100/125/140 with cylinder deactivation (from ~2017) engine: faults and reliability

Ford 1.0 EcoBoost (Fox) version

With caution

Ford's 2023 recall in the US over the oil pump belt tensioner covers cars of this generation (Focus up to 2018 and EcoSport up to 2022), so the risk of seizure from this belt did not disappear with cylinder deactivation.[1][2]

Years
2017–2019
Power
100–140 hp
Faults that affect it
3
2 of high or critical severity
Cars that use it
10
in our database

14 sourcesHow we work

What changes in this version

Ford added a 140 hp version and single-cylinder deactivation at low load, with a dual-mass flywheel and damped clutch disc to reduce vibrations. According to the Spanish press, this generation kept at least the oil-pump belt running in oil.[3][4]

Engine codes of this version: M1JC, M1JJ, M1JU.

Faults of the M1JC engine

The documented engine faults that affect this version and its years, from most to least important.

  1. 1Critical severityFrequency: CommonTimingDegradation of the timing belt running in oilYes: the 1.0 EcoBoost's timing belt runs in oil and can degrade over the years, shedding bits of rubber that block the oil pump and seize the engine without warning. The NHTSA is investigating the case in the United States and Ford has shortened the recommended replacement interval.Repair (garage): €800–€1,200
  2. 2Critical severityFrequency: CommonLubricationOil pump belt and tensioner failureYes. In addition to the timing belt, the 1.0 EcoBoost has a second belt, also running in oil, that drives the oil pump. If the tensioner breaks, the belt loses teeth and can cut off oil pressure; in the US Ford has recalled more than 100,000 Ford Focus and EcoSport vehicles for this reason.
  3. 3Medium severityFrequency: OccasionalIgnitionMisfires and engine warning light caused by the wiring harnessFord documented in a technical service bulletin that the engine wiring harness can rub against the exhaust heat shield on the 2018-2019 automatic EcoSport, which turns on the engine warning light with misfire fault codes. Spark plugs and coils are also common wear items on this turbocharged three-cylinder.

Cars fitted with the M1JC engine

Open each car to see all its faults with this engine and what to check before buying it.

Ford

Frequently asked questions

Is the M1JC engine reliable?

Our verdict is “With caution”. Ford's 2023 recall in the US over the oil pump belt tensioner covers cars of this generation (Focus up to 2018 and EcoSport up to 2022), so the risk of seizure from this belt did not disappear with cylinder deactivation.[1][2]

What faults does the M1JC engine have?

The documented ones that affect this version, by importance: degradation of the timing belt running in oil (critical severity), oil pump belt and tensioner failure (critical severity) and misfires and engine warning light caused by the wiring harness (medium severity).

Which cars use the M1JC engine?

Ford Fiesta VIII (2017–2023), Ford Focus III (2012–2018), Ford Focus IV (2018–2025), Ford C-Max II (2013–2019), Ford B-Max (2012–2017), Ford EcoSport (2014–2022), Ford Puma (since 2019), Ford Transit Courier (since 2014), Ford Tourneo Courier (since 2014) and Ford Transit Connect (2013–2019).[1][2][3][4][5][6][7][8][9][10][11][12][13][14]

Are you buying a car with the M1JC engine?

We will put you in touch with a partner only if you authorise it in the form.

Do you have a car with this engine? Tell us which faults you have had and at how many kilometres. Report your fault.

Sources

Every fact on this page links to its source. If you find an error, let us know.

  1. Ford's Self-Clogging 1.0-Liter EcoBoost Engine Is Finally Getting RecalledThe Drive · Motoring press · consulted 26 September 2026
  2. The Largest Ford EcoBoost Recalls In 15 Years Of ProductionCarBuzz · Motoring press · consulted 26 September 2026
  3. Ford EcoBoost engineWikipedia · Other source · consulted 26 September 2026
  4. Stellantis no es el único afectado por la correa de distribución bañada en aceiteAutofácil · Motoring press · consulted 26 September 2026 · in Spanish
  5. El Ford Focus estrena versiones mild hybrid de hasta 155 CV y se gana la etiqueta ECO de la DGTMotorpasión · Motoring press · published June 2020 · consulted 26 September 2026 · in Spanish
  6. El Ford Focus estrena etiqueta ECO con el nuevo EcoBoost HybridDiariomotor · Motoring press · consulted 26 September 2026 · in Spanish
  7. Gripa el motor por problema en el manguito se queda sin refrigeranteOpinautos · Owners' forum · consulted 26 September 2026 · in Spanish
  8. Ford B-MAX Trend 1.0 EcoBoost 100 CV (2012-2018): precio y ficha técnicakm77 · Technical documentation · consulted 26 September 2026 · in Spanish
  9. Self-Clogging Ford Oil Pumps Lead Feds to Investigate 1.0-Liter EcoBoost EnginesThe Drive · Motoring press · consulted 26 September 2026
  10. Timing Belt in Oil for Ford EcoBoost 1.0LIndustrias Dolz · Technical documentation · consulted 26 September 2026
  11. 1.0L EcoBoost - Automatic Transmission - Illuminated MIL With Multiple DTCs (TSB 19-2168)Ford Motor Company · Manufacturer · published 28 May 2019 · consulted 26 September 2026
  12. El nuevo Ford Puma 2019 es un crossover pequeño, semihíbrido y con etiqueta ECOHíbridos y Eléctricos · Motoring press · consulted 26 September 2026 · in Spanish
  13. Prueba Ford Tourneo Courier 1.0 EcoBoost 100 CV Sport: mucho coche por muy pocoAutonoción · Motoring press · consulted 26 September 2026 · in Spanish
  14. Ford Transit Connect (tabla «Technische Daten», segunda generación 2013-2023)Wikipedia (de) · Other source · consulted 30 October 2026 · in German