2014 Mercedes-Benz B-Class Problems: 8 Known Issues

On the 2012-2018 Mercedes-Benz B-Class M270 DE16 1.6L turbo, owners of W246 B-Class cars with the 1.6-litre M270 petrol engine report a rattle at start-up and stretched timing chains. A 2011 B 180 was diagnosed by a Mercedes workshop with a stretched chain at 75,000 km, 2012 1.6-litre cars needed a new chain and sprockets (one also a camshaft adjuster and cylinder head), and a pre-facelift B 180's chain apparently jumped, damaging the engine. Applies to: Second-generation (W246) B-Class with the 1.6-litre M270 petrol engine (M 270 DE 16: B 180 and B 200), model years 2012-2018; not sold in Canada. One further report concerns a 2.0-litre B 200 Natural Gas Drive whose cold-start rattle returned after a tensioner replacement; no report was found for the 2.0-litre B 220 or B 250, and a forum regular says none has been posted. Not the diesel or electric models. Mileage when it happened, as stated in the linked owner reports: 26,000 km (about 16,200 miles), 75,000 km (about 46,600 miles) on a 2011 and 80,000 km (about 49,700 miles) on a 2012.

On the 2012-2018 Mercedes-Benz B-Class, on certain vehicles, electrostatic discharge combined with a broken clock spring and insufficient grounding of the steering components could inadvertently deploy the driver's frontal airbag. An unintended deployment could startle the driver and cause a crash, and could cause minor injuries. Applies to: Certain 2012-2018 model-year B-Class sold in Canada, as listed in Transport Canada recall 2017-490 (also C, CLA, E, GLA, GLC and GLK). The record notes that a broken clock spring shows a driver airbag warning message and a red airbag warning lamp. Only a Mercedes-Benz dealer can confirm whether a specific VIN is included.

On the 2013-2019 Mercedes-Benz B-Class, on certain vehicles, the power steering control unit may corrode, letting moisture in so that it fails. That could cause a loss of power steering assist and a sudden increase in steering effort, especially at low speed, increasing the risk of a crash. Applies to: Certain 2013-2019 model-year B-Class (W246) sold in Canada (B 250) that were originally sold or ever registered in areas of heavy road salt use (Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland & Labrador), per Transport Canada recall 2020-617 (Mercedes-Benz 4694202) and its expansion 2021-507 (Mercedes-Benz 4694203); CLA and GLA are also listed. Only a Mercedes-Benz dealer can confirm whether a specific VIN is included.

On the 2012-2019 Mercedes-Benz B-Class, owners of W246 B-Class cars with the 7G-DCT dual-clutch automatic describe a pause of about a second before the clutch bites when pulling away, and jerking or harsh shifts at low speed. One owner of a high-mileage 2014 B 220 CDI reports judder that a transmission reset did not cure; the cause was not diagnosed in the thread. Applies to: Second-generation (W246) B-Class with the 7G-DCT automatic: model years 2012-2018 in Europe and 2013-2019 in Canada (B 250), with the M270 petrol (1.6 and 2.0 litre, including the B 200 Natural Gas Drive), OM651 diesel or OM607 1.5-litre diesel. The owner reports linked here are from a B 200, a B 200 CDI and a 2014 B 220 CDI. Not the B250e electric (W242), which has a single-speed drive unit, and not manual-gearbox cars. Mileage when it happened, as stated in the linked owner reports: 3,200 km (about 2,000 miles), 110,000 km (about 68,400 miles) on a 2016 and 230,000 km (about 142,900 miles) on a 2014.

On the 2014-2017 Mercedes-Benz B-Class Electric Drive, owners of the B250e electric B-Class describe a high-pitched whine or "dentist drill" noise from the drive unit under acceleration that gradually gets louder. One owner reports the dealer diagnosed the noise as needing a new motor; other owners speculate about motor bearing wear, which the reports do not confirm. Applies to: Only the B250e (B-Class Electric Drive, W242), the battery-electric version of this generation; owners note its drive unit came from Tesla. Gasoline and diesel B-Class models are not affected. Some motor sound at low speed is normal; owners point out that a pedestrian-warning sound is also emitted at low speed. Mileage when it happened, as stated in 6 of the linked owner reports: from 32,000 to 90,000 miles.

On the 2012-2019 Mercedes-Benz B-Class, w246 owners report a parking-brake malfunction warning, and in one case the electric parking brake worked on one side only. One owner found water in the left rear actuator motor and replaced both actuators, but the warning stayed until the parking-brake control module connectors inside the right rear of the car were unplugged and reseated. Applies to: Second-generation (W246) B-Class with the electric parking brake: model years 2012-2018 in Europe and 2013-2019 in Canada (B 250). The owner reports linked here include a 2012 car. Owners report the rear actuator motors, the wiring and the control module as the parts involved; the cause on a given car must be diagnosed.

On the 2012-2018 Mercedes-Benz B-Class OM651 DE18 LA / DE22 LA diesel, owners of W246 OM651 diesel B-Class cars report the engine warning light with a particulate-filter fault. On a 2013 B 200 CDI the fault "particulate filter overloaded" returned after a sustained drive at higher engine speed; on a 2014 B 220 CDI the workshop first found a faulty differential-pressure sensor and then replaced the particulate filter. Applies to: Only diesel W246 B-Class models with the OM651 engine (B 180 CDI 1.8, B 200 CDI, B 220 CDI), model years 2012-2018, mainly cars used for short trips. Not the B 160 CDI or B 180 CDI with the Renault-sourced 1.5-litre OM607, and not petrol, natural-gas or electric models; the Canadian B 250 is petrol only. Mileage when it happened, as stated in the linked owner reports: 20,000 km (about 12,400 miles) and 123,000 km (about 76,400 miles) on a 2013.

On the 2012-2019 Mercedes-Benz B-Class, owners of W246 B-Class cars with the M270 petrol engine report coolant warning messages, an engine warning light with the temperature stuck around 70-80 C, or the gauge swinging, with dealers replacing an electronically controlled thermostat that stuck open. Some gauge movement is normal on this engine, and owners report a dealer engine-software update that steadied it where no hardware fault was stored. A thermostat replacement did not always cure it: other causes found were a crack elsewhere in the cooling system and a stuck valve in the water pump. Applies to: Second-generation (W246) B-Class with the M270 petrol engine (B 180, B 200, B 220 4MATIC, B 250): model years 2012-2018 in Europe and 2013-2019 in Canada (B 250). The owner reports linked here are from a B 220 4MATIC, a 2012 B 200 and other W246 petrol cars. Not the diesel or electric models. Mileage when it happened, as stated in the linked owner reports: 65,000 km (about 40,400 miles) on a 2013, 74,000 km (about 46,000 miles) on a 2012, 142,000 km (about 88,200 miles) on a 2012 and 176,000 km (about 109,400 miles) on a 2012.