Mercedes-Benz B-Class: common faults & what to check
Thinking about buying a used Mercedes-Benz B-Class (2005–2019) in New Zealand? We've documented 9 known faults for this model spanning transmission, engine, suspension, and cooling. Each researched and verified before it's published. The most serious issues here are rated critical. Two are set out in full below — the rest, with the symptoms, repair costs and checks for each, are free with an account.
9
Documented faults
Critical
Most serious
$1,800–$4,000
Typical repair
4
Systems covered
Known Mercedes-Benz B-Class faults
Every fault below is documented specifically for this model — researched and verified before it’s published.
01Autotronic CVT (722.8) shudder, jerking and failure (W245)
CriticalCommonTransmission $4,000–$8,000 to fix
The first-generation B-Class shares the A-Class's Autotronic continuously variable transmission, and it is the generation's most expensive weak point. The belt/pulley pack and its electrohydraulic control unit wear out, causing shudder pulling away, hesitation, flaring revs and eventually limp mode or no drive. Mercedes treated the fluid as 'sealed for life', which accelerated wear, so a car with no CVT fluid history is higher risk. A rebuild or replacement usually costs more than a tidy W245 is worth.
Symptoms to notice
Shudder or juddering when pulling away
Revs rise but speed does not follow
Hesitation or jerk when accelerating from a stop
Transmission warning symbol on the dash
Slips into limp mode on a longer test drive
What to check
Test drive from cold and again after 15-20 minutes. Pull away gently then briskly and feel for shudder or slipping; watch the tacho for revs climbing without matching acceleration. Ask for invoices proving the CVT fluid has been changed. Any transmission warning light after the car warms up is a walk-away.
Where to look: Transmission, mounted transversely behind the engine under the front floor
Ask the seller
“Has the CVT fluid ever been changed, and can I see the invoice?”
“Has the transmission ever been rebuilt or replaced?”
“Does it ever shudder or hesitate pulling away from lights?”
02Front suspension knock and premature wear (W245)
MinorCommonSuspension $400–$1,400 to fix
The tall, city-driven W245 wears front suspension bushes, drop links and lower arm ball joints faster than owners expect, producing knocking and rattling over bumps. It is not catastrophic but it fails NZ WoF checks and adds up if several parts need doing at once. Worth budgeting for on any high-kilometre example.
Symptoms to notice
Knock or clunk over bumps and speed humps
Rattle from the front on rough roads
Uneven front tyre wear
What to check
On the test drive, cross a rough patch or driveway lip at low speed and listen for knocking from the front. Grab each front tyre top-and-bottom and rock it for play. Check the front tyres for uneven or feathered wear.
Where to look: Front suspension - control arm bushes, ball joints and anti-roll bar drop links
Ask the seller
“Have any front suspension bushes or links been replaced recently?”
“Does it knock over bumps?”
TransmissionMajor
EngineMajor
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TransmissionMajor
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CoolingMinor
7 more documented faults on the Mercedes-Benz B-Class
Symptoms, what to check, where to look and what to ask the seller — for every fault above. Free with an account, no card needed. One account covers one vehicle, so make it the car you’re actually looking at.
This page covers the model. Enter the plate of the actual car you’re looking at and see its year, engine, safety rating and register flags — free, no account needed.
Like any used car, it depends on the specific example and its service history. Across the 9 documented faults for the Mercedes-Benz B-Class, the recurring problem areas are transmission, engine, and suspension. A Mercedes-Benz B-Class with a full service history and no signs of the issues listed on this page can be a sound buy but each one needs to be checked individually before you commit.
What are the most common problems with a used Mercedes-Benz B-Class?
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We've catalogued 9 known faults for the Mercedes-Benz B-Class, covering transmission, engine, and suspension. Two are written out in full on this page. The rest — with the symptoms to notice, what to inspect, and typical repair costs for each — are free once you create an account.
How much do repairs cost on a Mercedes-Benz B-Class?
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Most single repairs on the Mercedes-Benz B-Class fall between $1,800–$4,000 at NZ independent-workshop rates. Some of the 9 documented faults cost less and a few cost considerably more, and no one car needs them all. Knowing which ones to look for before you view is what lets you negotiate the price down or walk away.
Should I get a pre-purchase inspection on a Mercedes-Benz B-Class?
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Yes. A Mercedes-Benz B-Class inspection focused on its known weak points is the single best way to avoid an expensive mistake. KickTyres gives you a guided, model-specific inspection plus a market valuation and negotiation figure for $17.90 far less than the cost of missing one of the faults on this page.