Control units and comfort electronics Fiat: problems by model and engine

Documented faults, from most to least important

Severity × frequency. Below each one, the Fiat models it appears in.

- Medium severityFrequency: Very frequentFiat StiloElectrical and electronic faults in the multiplex systemThe Stilo has had a reputation for widespread electrical faults since its launch: poor contacts in the multiplex wiring, an instrument cluster that switches off and sensors that disconnect, sometimes while the car is running.
- High severityFrequency: OccasionalFiat ArgoWater ingress into the engine control unit that can stall the car while driving (2025 campaign)Yes: in May 2025 Stellantis recalled 21,044 Fiats and 449 Peugeots in Brazil, including the 2025 Argos, because a defective part could let water into the engine control unit and switch off the engine with the car moving. The control unit is replaced free of charge, in about one hour.
- High severityFrequency: OccasionalFiat CronosWater ingress into the engine control unit that can switch off the car while driving (2025 campaign)Yes: in May 2025 Stellantis recalled 21,044 Fiats and 449 Peugeots in Brazil, among them the 2025 Cronos, because a faulty part could let water into the engine control unit and switch off the engine while the car is moving. The control unit is replaced free of charge in about one hour.
- High severityFrequency: OccasionalFiat MobiWater ingress into the engine control unit that can stall the car while driving (2025 campaign)Yes: in May 2025 Stellantis recalled 21,044 Fiat and 449 Peugeot in Brazil, including the 2025 Mobi, because a faulty part could let water into the engine control unit and stall the engine with the car moving. The control unit is replaced free of charge in about one hour.
- High severityFrequency: OccasionalFiat Strada IIWater ingress into the engine control unit that can stall the car while driving (2025 campaign)Yes: in May 2025 Stellantis recalled 21,044 Fiats and 449 Peugeots in Brazil, including 2025 Stradas, because a defective part could let water into the engine control unit and switch off the engine with the car moving. The control unit is replaced free of charge, in about one hour.
- Low severityFrequency: OccasionalFiat 500LWrong total mileage on the instrument cluster caused by an engine ECU software errorIn 2024 the KBA recorded a recall of 6,178 Fiat 500Ls (and 9,180 Fiorinos) built in 2021-2022 because a programming error in the engine ECU caused the instrument cluster to show an incorrect total mileage. It is fixed with a software update at an authorised workshop.
- Low severityFrequency: RareFiat Panda IIEngine cutting out due to a loose main relay, a damp ECU connector or a loose earthThe Dutch roadside assistance service ANWB flags three minor Panda II faults that stop the engine: the main relay in the fuse box that vibrates loose, damp in the engine control unit connector, and a loose earth cable.

By Fiat model

Open yours to see only the faults that affect it, by engine and by year.

Frequently asked questions

What faults with the control units do Fiat cars have?

In 7 models from Fiat there are 7 documented faults with the control units. The most important: electrical and electronic faults in the multiplex system, water ingress into the engine control unit that can stall the car while driving (2025 campaign) and water ingress into the engine control unit that can switch off the car while driving (2025 campaign). Each fault has its own page with the affected years and versions, the symptoms and the repair cost.

Which Fiat models have the most problems with the control units?

Fiat Stilo (1 fault), Fiat Panda II (1 fault), Fiat 500L (1 fault) and Fiat Mobi (1 fault).