Driving on with faulty ignition coils clogs the catalytic converter of your Peugeot 208 and leads to a bill of €1,000 or more. Early diagnosis of engine problems such as misfires (failed ignitions) or jerky running prevents this expensive repair. In this article you can read exactly which symptoms point to catalytic converter problems, how faulty coils are the cause and what you can do to stop this chain reaction before the damage becomes irreparable.
How faulty coils damage your catalytic converter
The catalytic converter converts harmful exhaust gases into less harmful substances via a chemical reaction. This takes place in a honeycomb structure with precious metals such as platinum and palladium. When a coil fails, a so-called misfire occurs: the spark is missing and the fuel does not burn in the cylinder.
That unburnt fuel ends up in the exhaust system. In the catalytic converter this fuel still burns, but this afterburning causes extreme temperatures. As a result the catalytic converter can overheat and suffer internal damage. At the same time, deposits form that clog the fine channels of the honeycomb structure.
In the Peugeot 208 coil failures are fairly common, particularly in older cars and engines with higher mileage. Many owners report that the engine warning light comes on, followed by loss of power and an irregular idle speed. Anyone who then keeps driving without having the fault repaired risks permanent damage to the catalytic converter within just a few dozen kilometres.
Symptoms of a faulty catalytic converter in the Peugeot 208
A damaged or clogged catalytic converter causes recognisable signals. These symptoms point to catalytic converter problems:
- Loss of power, especially when accelerating or pulling away
- Higher fuel consumption than normal
- Rattling or jingling noises under the car
- Engine warning light illuminated on the dashboard
- Strong smell of unburnt fuel or sulphur at the exhaust
- Car hesitates or runs poorly at idle
These signals occur because the catalytic converter becomes clogged or internally damaged. The engine can no longer expel exhaust gases properly, causing back pressure to increase. This leads to loss of power and inefficient combustion.
Note: these symptoms can also occur with other faults. If in doubt, have a diagnosis carried out with an extensive reading of fault codes (stored codes that indicate which engine sensors or components are reporting irregularities). A professional garage can then establish whether the catalytic converter itself is faulty or whether an underlying engine problem is the cause.
Coil failure leads to catalytic converter damage in the Peugeot 208
Ignition coils ensure that the spark plugs produce sparks to ignite the air-fuel mixture. When a coil fails, that spark is missing. The cylinder then no longer does any useful work and unburnt fuel ends up in the exhaust.
In the Peugeot 208 coil failures are more common in engines that are older than five years or have covered more than 100,000 kilometres. Causes include wear, heat build-up and moisture ingress. A faulty coil often causes jerky engine behaviour, especially at low revs or during acceleration.
Anyone who keeps driving with a faulty coil places a heavy load on the catalytic converter. The unburnt fuel causes afterburning in the converter, which can lead to internal melting. The honeycomb structure becomes clogged with soot deposits. This combination often results in a completely blocked or damaged catalytic converter core.
Many owners report that a coil defect initially seems like a minor issue, but escalates within a short time into a much more expensive repair. Replacing faulty coils at an early stage prevents this chain reaction.
Costs for replacing the catalytic converter on the Peugeot 208
A new catalytic converter for the Peugeot 208 costs between €600 and €1,200, depending on engine type and specification. On top of that come labour costs for removal and refitting, often between €200 and €400. Total replacement costs therefore fall between €1,000 and €1,600.
A used catalytic converter is a budget option. Second-hand units cost between €200 and €500, but their condition and remaining lifespan vary. When buying a used catalytic converter, always check its origin and, where possible, have its internal condition assessed before fitting.
According to the ANWB, a catalytic converter should last at least 10 years or 150,000 kilometres under normal use and maintenance. In practice, damage almost always occurs because of an underlying engine problem that was not resolved in time. Preventive maintenance on coils, spark plugs and the injection system is therefore cheaper than a new catalytic converter.
Practical tips to prevent catalytic converter damage
You can reduce the risk of catalytic converter damage through regular maintenance and taking swift action when faults occur. These measures help:
- Use the correct engine oil according to the manufacturer’s specification; the wrong oil can cause contamination in the exhaust system
- Have an engine warning light checked immediately and do not continue driving with a lit warning light
- Replace coils and spark plugs on time, preferably around 80,000 to 100,000 kilometres
- Have the lambda sensor checked regularly; a faulty sensor disrupts combustion and puts extra strain on the catalytic converter
- Avoid very short trips with a cold engine; in that case the catalytic converter less often reaches optimal operating temperature
- When you have exhaust problems, do not just have the catalytic converter replaced. Also trace the root cause of the problem
Car enthusiasts regularly share that preventive maintenance on coils and the fuel injection system (the system that sprays fuel under pressure into the cylinders) is cheaper than a new catalytic converter. Many forum users advise that if you notice a suspicious smell, rattle or fault code, you should not only have the exhaust checked but also have combustion and sensors inspected.
Checklist for maintaining your Peugeot 208
Keep an eye on these points to extend the lifespan of your catalytic converter:
- Check regularly whether the engine warning light comes on
- Have fault codes read out immediately if the engine runs irregularly
- Replace coils and spark plugs according to the service schedule or at the first signs of wear
- Always use engine oil that meets the manufacturer’s specifications
- Monitor oil and coolant consumption
- Have the lambda sensor checked during MOT tests or major services
- Do not drive for long with the engine warning light illuminated
These steps prevent minor faults from turning into costly repairs. The catalytic converter is not a separate wear item that simply wears out; in practice the condition of the engine determines its lifespan.
When should you take your Peugeot 208 to the garage?
Go to a professional garage immediately if you experience one or more of the following symptoms:
- The engine warning light is on or flashing
- The engine hesitates, jerks or suddenly loses power
- You can smell unburnt fuel or a sharp sulphur smell at the exhaust
- Rattling or jingling noises develop underneath the car
- Fuel consumption suddenly increases without an obvious cause
Have the garage carry out a full diagnosis with a scan of the engine management (the computer system that controls combustion, injection and ignition). Do not only check the catalytic converter, but also coils, spark plugs, lambda sensor and injection system. Fix the underlying fault first before replacing the catalytic converter, otherwise the damage often returns.
On the Carnews website you will find more information about common engine problems, maintenance tips and practical advice for the Peugeot 208 and other models. Discover which faults you can prevent and how to keep your car in optimum condition.
Frequently asked questions
The most common causes of catalytic converter damage in a Peugeot 208 are engine faults that allow unburnt fuel to enter the converter and overheat it. Using the wrong or contaminated engine oil can also cause deposits that clog the catalytic converter. In addition, continuing to drive for a long period with the engine warning light on or with other engine problems often leads to consequential damage to the catalytic converter. Finally, mechanical damage and wear at high mileage can increase the risk of catalytic converter damage.
Always use the engine oil specified by Peugeot and make sure regular maintenance (spark plugs, coils, injection, lambda sensor) is carried out on time. Have a lit engine warning light, irregular engine behaviour or loss of power read out and fixed immediately so that unburnt fuel does not enter the catalytic converter. Avoid consistently driving only short trips with a cold engine, so that the converter regularly reaches operating temperature and does not clog up. In the event of exhaust or catalytic converter problems, always have the underlying cause in the engine system traced and repaired as well.
Early signs of a faulty catalytic converter in your Peugeot 208 include noticeable loss of power and clearly higher fuel consumption. You may also hear a rattling noise under the car, especially when accelerating or driving over speed bumps. In addition, a lit engine warning light (check engine) is an important warning. Sometimes you can smell a strong odour of unburnt fuel or a rotten-egg/sulphur smell at the exhaust.
Many short trips with a cold engine shorten the life of the catalytic converter, because it will rarely reach its optimal operating temperature and becomes contaminated more quickly. Driving with engine faults (such as misfires or an illuminated engine warning light) causes unburnt fuel in the exhaust, which can overheat and damage the converter. Driving for too long with oil consumption or the wrong/worn oil can create deposits that clog the catalytic converter. Irregular maintenance of ignition and injection components (spark plugs, coils, injectors, lambda sensor) leads to poor combustion and therefore extra strain on the catalytic converter.
Yes, using the right fuel is important for the lifespan of the catalytic converter in your Peugeot 208. Always fill up with the specified fuel (for petrol, do not use E10 if Peugeot does not approve it for your engine) and avoid experimental or aggressive additives that are not approved by the manufacturer. Additives that significantly alter combustion or contain a lot of metals/silicates can, over time, cause deposits or overheating in the catalytic converter. Stick to the fuel specifications in the owner’s manual and only use additives that are explicitly recommended by Peugeot or an approved garage.