Tyre wear, broken springs, lighting issues and worn brakes regularly cause the Volvo S40 to fail the MOT test. Older examples in particular show wear on suspension components and electrical systems. With timely checks and targeted maintenance, you can avoid unpleasant surprises at the test centre.
Common MOT failures with the Volvo S40
The Volvo S40 is known as a safe and reliable mid-size car, but defects still appear during the MOT on older examples. This Volvo S40 has specific vulnerabilities that become more pronounced with age and use. Lighting, brakes, tyres and suspension are the main points to watch.
Lighting and electrical faults
Problems with lighting are a frequently mentioned reason for failure. With the S40, it mainly concerns defective dipped-beam or tail lights, fog lights that do not work and number plate lights that cut out. Faults caused by moisture in connectors or poor contacts also occur. That is why you should check all the lights around the car beforehand.
Also test the operation of the brake lights, indicators and number plate lighting. Replacing a defective bulb costs little money, but can still lead to an MOT fail if you ignore it. In the case of electrical faults in the wiring, diagnosis is needed to trace the cause.
Brakes and wear
Brakes are a classic MOT item. With the Volvo S40 several problems play a role:
- Worn brake pads or discs
- Sticking brake callipers
- Unequal braking difference between left and right
- Handbrake that does not work sufficiently
Cars that cover few miles can suffer from rust on the discs. On examples with high mileage, natural wear is more often the cause. If in doubt, also have the brake lines and handbrake cables checked. On a test drive, the car should brake in a straight line, without vibrations or jolts.
Tyre wear and wheel suspension
Tyres are a simple but important inspection item. Watch out for insufficient tread, uneven wear, cracks due to ageing and differences in size or type where these are not allowed. Uneven wear often points to problems with tracking or suspension.
For the MOT, the minimum tread depth is 1.6 millimetres across the full width of the tyre. In practice, it is wise to consider new tyres from 3 millimetres, because grip and safety are already reduced by then. Also check whether the tyres are wearing evenly across the full width.
Broken springs and suspension
Wear on underbody components is quite common on the S40 as it ages. Broken springs are a known reason for failure on older examples. Other MOT issues include worn control arm bushes, play in ball joints, worn anti-roll bar links and track rod ends or steering joints with play.
You often notice this by knocking noises over speed bumps, vague steering or uneven tyre wear. Have the front suspension checked if you can get the car onto a lift. Many problems are then visible to the naked eye. Cracking in rubber bushes is also a sign that replacement is needed.
How do I prepare my Volvo S40 for the MOT?
Good preparation prevents unnecessary failures. Start with a thorough check of all exterior lights. Then test the operation of the windscreen wipers and washers, as these also regularly attract comments. Inspect the windscreen for stone chips or cracks, check the tyre set including the spare wheel if present, and test the braking performance and handbrake.
Also listen for steering and suspension noises during a test drive over uneven road surfaces. This quickly reveals whether there is play in suspension or steering components. Check the exhaust for leaks and mounting, pay attention to dashboard warning lights such as the engine management light, and check fluid levels and visible leaks under the car.
Practical checklist
Work through the following points before the test:
- All lighting around the car
- Tyre set with sufficient tread
- Braking performance and handbrake
- Windscreen wipers and washers
- Windscreen for stone chips or cracks
- Steering and suspension noises
- Exhaust for leaks and mountings
- Dashboard warning lights, especially engine management
- Fluid levels and visible leaks
An S40 that has covered few miles can suffer from sticking brakes or dried-out rubber bushes. With diesel versions it is sensible to have a diagnostic check carried out beforehand if there have ever been engine faults. An illuminated engine management light is almost always a reason to have diagnosis carried out first before going for the test.
Repairing a broken spring on the Volvo S40
A broken spring is a very common defect on older Volvo S40s and always leads to failure. The spring can break due to material fatigue, corrosion or overloading. You notice a broken spring by knocking noises, a car that leans to one side or a hard, uncomfortable ride.
Repair consists of replacing the spring; it is often recommended to replace both springs on the same axle. This prevents differences in ride height and driving behaviour. Costs vary depending on the type of spring and the version of the car. At many garages, the shock absorbers are also checked to see if they are still in good condition, as they are often replaced at the same time as the springs.
Recognising a broken spring
Symptoms that point to a broken spring are:
- Knocking noise over uneven surfaces
- Car leaning to one side
- Hard, uncomfortable suspension
- Uneven tyre wear
If in doubt, you can visually inspect the springs. Put the car on a ramp or lift and see whether you can spot a break or crack in the spring. Sometimes the break is on the inside and difficult to see. A garage can quickly check this during an inspection service.
Exhaust and emissions at the MOT
With older petrol and diesel versions of the S40, the MOT can be strict on exhaust gas values and leaks. Common issues include leaking exhaust parts, rusty hangers or mountings, fault codes in the engine management system and a worn lambda sensor or EGR-related problems on diesels.
Diesel variants in particular can be sensitive to contamination in the exhaust system and emission components. On diesel S40s, EGR problems and contamination are mentioned relatively often. This can lead to reduced pulling power, fault messages in the engine management, rough idling and smoke. For the MOT, this mainly means a risk of emission issues and warning lights.
‘ Surface rust may look harmless, but on load-bearing parts or brake components it can definitely lead to failure. ’
Rust and bodywork
The Volvo S40 is not notorious for severe rust problems like some older cars, but rust spots can certainly occur. Pay particular attention to wheel arches, sills, subframe and suspension mounting points, exhaust hangers and brake lines. Surface rust may look harmless, but on load-bearing parts or brake components it can definitely lead to failure.
On older examples also inspect the condition of the underside. Heavy rust on the subframe or the mounting points of the suspension can be a sign of poor care or prolonged exposure to salt and moisture. If in doubt, have a garage assess this beforehand.
Model-specific points to watch
On manual S40s, a slipping clutch or worn gearbox components can indirectly affect the test, for example if the car drives poorly or makes noise. This is not always a direct MOT failure, but it is a sign that maintenance is needed.
With some automatics, jerky or delayed shifting occurs. If the gearbox does not shift properly or the car responds unpredictably, this is not a direct standard failure item, but it is a technical warning that requires serious attention.
Tips from practice
A car with a complete service history inspires much more confidence than one with no demonstrable maintenance. Minor faults in lighting or sensors are often cheap to fix, but can still lead to failure if you ignore them. With older S40s it is better to take a test drive over uneven road surfaces so you can quickly hear whether there is play in suspension or steering components.
Anyone who drives or wants to buy an S40 would be wise to check lighting, brakes, suspension, steering components, tyres, exhaust and rust especially carefully. With timely maintenance the S40 can usually be kept well ready for the MOT, but on this model overdue wear quickly shows up in test costs.
On the Carnews website you will find more articles about common problems with the Volvo S40 and other car brands. Discover useful tips, maintenance advice and practical guides to keep your car in top condition.
Frequently asked questions
The most common MOT failure points on the Volvo S40 are defective lighting, worn or unevenly operating brakes, play or worn bushes in the suspension/steering, tyres with too little tread or irregular wear, and leaks or rust on the exhaust. You can spot them in time by regularly testing all the lights (including brake and number plate lighting), paying attention to vibrations or the car pulling to one side when braking, knocking noises or vague steering over speed bumps, and checking your tyres for tread depth and uneven wear. Also watch for rust on the underbody and exhaust, and for an illuminated engine management light, which may indicate emission problems. A periodic inspection on a lift before the MOT helps to detect wear on suspension, brake lines and rust patches at an early stage.
Typical repair costs for common MOT defects on a Volvo S40 are roughly: a few tens up to about €100 for lighting (bulbs, contacts), around €150–€400 per axle for brakes (pads/discs, sticking calliper) and approximately €100–€300 for simple exhaust repairs or a silencer section. For suspension/steering parts (control arms, ball joints, anti-roll bar links) you usually need to reckon with about €150–€400 per axle, while replacing tyres often costs between €250 and €500 per set. Wiper blades and minor visibility/washer issues are usually resolved for under €50–€100. All amounts are indicative garage prices including labour and can vary by garage, region and the exact version of the S40.
Yes, you can prevent many common MOT defects on your Volvo S40 yourself by checking all lights (including brake and number plate lights), windscreen wipers and washers before the test and replacing defective bulbs or wiper blades straight away. Also check the tyres for tread depth, cracks and uneven wear and listen during a drive for knocking or humming from the suspension or steering. Inspect the exhaust for leaks/rust and make sure no engine management light is illuminated; if in doubt, have fault codes read first. Finally, it pays to have the brakes cleaned or moved regularly (avoid long periods of standing still) and to do a short brake test to spot pulling or juddering.
On the Volvo S40, MOT inspectors particularly notice wear on brakes (brake pads, discs, callipers and handbrake), suspension and steering (control arm bushes, ball joints, anti-roll bar links, track rod ends) more quickly. Rust or corrosion on brake lines, load-bearing parts and exhaust (mountings) also relatively often leads to failure. In addition, defective lighting and worn or unevenly worn tyres regularly cause MOT failure.
Yes, in practice the common MOT defects mainly differ by age group/model year: older S40s relatively more often suffer from wear on the suspension (control arms, bushes, steering components), rust on the exhaust/brake lines and ageing lighting/electrical contacts. Diesel variants (especially older generations) more often have EGR/emission issues and fault codes that can lead to failure. When buying or testing, pay extra attention to: a complete service history, condition of the underbody and brakes, rust on load-bearing parts/brake lines and exhaust, and whether any warning lights are illuminated. Always take a test drive over speed bumps and uneven road surfaces to detect knocking noises or vague steering (play/wear).