Peugeot 406 with mileage: holes in the sills are not a problem if the BSI unit is okay


The body is all-steel, with typical mid-90s proportions and interior volume typical of the D-Class of those days. All exterior panels are galvanized, but only on the outside. In addition to the classic sedan were also available coupe and wagon.

The arrangement of the engines was transverse, the drive was strictly front-wheel drive, and the suspensions were McPherson and multilever. Motors – a wide range of simple atmospheric gasoline engines (1.6, 1.8, 2.0, 2.2), one 2-liter gasoline turbo, 2.9-liter V6, as well as diesels, strictly four-cylinder, from 1.9 to 2.2.

Restyled versions here are very different from the restyled in “stuffing” (more about that below). It is also interesting that many of the technical solutions which were ‘run through’ on the 406 model will be typical for many Peugeot-Citroen models for years to come.


March, 1995. Production start.

September 1995. Start of sales in France, only with sedan body. The engine lineup is very wide from the start: there are petrol atmobiles 1.6 (XU5M3 88 hp), 1.8 (XU7JB/XU7JP4 90 / 110 hp), 2.0 (XU10J3R 132 hp) and 2.9 V6 (ES9J4 190 hp). ), “turbo” 2.0 (XU10J2TE 147 hp) and diesels: 1.9 atmospheric (XUD9SD 75 hp) and turbocharged, with direct injection, but without Common Rail 1.9 (XUD9TE 90 hp) and 2.1 (XUD11BTE 109 hp).

February 1996. Sales launch in England and Germany.

October 1996. Introduced the 406 model coupe, only with 2.0 and 2.9 gasoline engines. Also introduced the 406 model station wagon, it is designated as Break.

February 1999. Restyling of the model in sedan and station wagon bodies. Optics, body panels, trim and equipment were updated. All engines were also changed. DW10 2.0 (90-110 hp) and DW12 2.2 (133 hp) diesel engines are already with Common Rail system. Gasoline engines are also in a new series, 1.8 EW7 (116 hp), 2.0 EW10J4 (135/136 hp) and 2.2 EW12J4 (158 hp). The 2.9 engine was updated, now the ES9J4S (207 hp).

June 2001. Re-styled coupe. Appearance changes, new engines: gasoline 2.2 (158 hp) and diesel 2.2 HDi (133 hp). New electronics with multiplex units.

July 2001. Modernization of the electronics of the sedan and station wagon body cars. Hub architecture with multiplexed bus and BSM/BSI blocks, as on the next generation of PSA platforms. A direct injection 2.0 EW10D (140 hp) engine appears in the engine lineup.

June 2003. The second restyling of the coupe. This time it had serious exterior changes. The equipment is basically unchanged.

December 2003. The successor of the model, the Peugeot 407, is introduced.

May 27th, 2004. Peugeot 407 starts serial production, the 406 sedan is removed from production.

Autumn 2004. The Peugeot 406 Break station wagon is taken out of production.

May 2005. Withdrawal from production of the 406 Coupe.


Exterior panels.

Peugeot was one of the first companies to offer galvanized body panels. And the “French scheme” with single-sided galvanizing turned out to be the most successful solution, if we look at the situation from the present moment. It gave the cars a very good body life with minimal maintenance and was much cheaper than the two-sided hot-dip galvanized sheet metal method that VW used until the late ’90s. Don’t be surprised, if you see Peugeot 405, the ancestor of the hero of the present review, in excellent condition and without any signs of restoration. Under a number of conditions, the body turns out to be very survivable.

The Peugeot 406 is not only galvanized, but also well painted. Especially the cars produced before 2001-2003 years, the paintwork of which can look like new with a little maintenance. The later cars, unfortunately, are painted in a changed technology, and they have such an unpleasant defect, as varnish peeling, and chips are formed more often.

The biggest trouble with the body is the sills. The rotting process begins in the rear part, and usually it affects the inner reinforcement. And in neglected cases – even the base of middle strut, outer parts of body floors, attachment points of rear suspension longitudinal arm and rear arches.

Rotten front fenders are a massive problem, but relatively inexpensive. And it can be solved forever by installing plastic fenders. But even the treatment of the inner surface of a fender usually saves the situation quite well, if there is no “fringe” on the edge yet. The fender support surface on the upper booster under the headlight also rusts. If the fender is dangling, you probably need to weld on a new bracket.

The hood, which has a rusty front edge, can not be repaired well. The frame itself “plays”, breaking the sealant, the lock is relatively weak, with age it has gaps in the working pair, and the hood because of him vibrates. It’s difficult to correct this problem, unless you do the anticorrecting more often. And yes, the hoods of the cars before and after restyling are incompatible, they even have different hinges.

The corrosion process on the 406 almost always starts from inside, and the outer problems are always a consequence of the presence of mud pockets in inner cavities, or, as in case with the front fenders, a big and badly protected surface without zinc coating. Sometimes cars, even at 20 years old, can be if not perfect, then very decent externally, and there are a lot of problems hiding inside.

From below

Holes in thresholds are not so terrible, if a reinforcing device and all other elements are intact inside. The outer sill itself is on sale and costs less than 2000 rubles per side. The quality is quite acceptable, installed without problems. The problem is something else: when the appearance of dirt and moisture in the thresholds affects a lot of externally inconspicuous elements of the power structure. Both the amplifier and the side panel elements, joints with the sill and arches, rot away. You can check the condition by assessing the joint between the sill reinforcement and the body floors (it is advisable to wash it beforehand) or by looking under the body carpets.

If the interior is dry, the most you’ll find is some rust around the edges of the drain plugs under the seats. If the sills have rotted badly, there will be damage to the outside seams and the sealant on them. There is no galvanizing on the inside, and if there was rust, it quickly comes out again. But a lot of rust on all floor surfaces is usually the result of moisture. The floor carpet here doesn’t dry well, and the paintwork on the interior surfaces is weak. So a clogged drain, leaks into the interior from doors, sunroof, or climate control drains are very bad for the body.

Front fender

In addition to all of the above, the French laid at least one very unusual problem in the design. Moisture can get inside the box body elements through the arches, if the lockers or brackets are not properly fixed, just through the fixing windows of a variety of plastic. Dirt and moisture in the longitudinal floor spar not only harms the front subframe mounting bolts, but also contributes to the penetration of moisture into the interior, under the carpet.

The side trunk recesses also rust, but it’s usually little noticeable on the outside. But inside the rear arch there’s a lot to look at. But first you need to remove the lockers. The area at risk is the area behind the fuel filler pipes and the edge of the arch next to the spring.

And in general, if the car was driven in the countryside, and the underbody was not washed very thoroughly, surprises are possible. Corrosion of the underbody elements in the rear part of the body also happens and in most cases is connected exactly with the condition of the cabin floor or sills. Also the mounts of rear underframe and various brackets are rusty – you will see it at once.

There are cars with superficial corrosion and destroyed zinc coating, while the floors of a saloon and a trunk are dry and even the spare wheel niche is not rotten from inside.


Due to the age of the cars, one may face breakages and deterioration of almost any elements. A worn-out headlights and windshield could not be mentioned. Fog lights are leaky, and the reflector corrodes with time. The rearview mirrors have a corroded spring and aluminum frame, causing the folding mechanism to jam.

The rear emblem on the trunk is peeling and falling apart on almost everyone. Damp taillights are also found in the rear lights. Broken fasteners and broken lip at the front bumper, unfortunately, are also common.

Wear of door hinges is almost always there, but the seals and locks fail mainly at the rear door of station wagons. Failure of window lifters – the trouble is usually electric, the mechanical part is strong enough, it suffers mainly from smokers, who often move window back and forth. The windshield wiper blade is not reliable; with long idle time it seizes up with warranty. By the way, on sedans before a restyling there is also a rear window wiper.


The quality of the interior is quite high, especially for variants after restyling, when improved the quality of materials and removed frankly cheap packages. Up to ’99, there were even dashboards with a clock instead of a tachometer – a legacy of times gone by.

Wear of steering wheel and seats should not surprise, and not only leather steering wheels are worn out, but even plastic ones, which are frayed by scales. It is necessary to note the unsuccessful construction of door cards, the fabric coverings sags because of ageing of foam padding. The headliner is also prone to sagging, especially after wet dry-cleaning.

The dashboards often fail – both the displays and the arrow indicators. Breakdowns of the on-board computer display, multimedia system failures also happen regularly: somewhere the repair is possible by replacing the plume, but more often they are replaced as a whole, since there are few repair specialists in our country. But in Belarus, the restoration of interior elements and interior equipment on the 406 is already well established, the car is in high demand there because of the abundance of diesel engines and low price.

The air conditioning in the 406 is quite strong. The most typical malfunction is a breakdown of the heater fan or its regulator. Also the actuator of recirculation flap often fails – it is electric on all cars.

With a fan, everything is usually simple: first of all, brushes are failing, and in a regulator, in cars after a restyling, a few copeck elements get burnt. Ostensibly indestructible plastic case in fact is opened perfectly, there are no special difficulties with repair.

The recirculation actuator breaks because of a penny pinion, it just breaks along the axis. The part is on sale now, it is printed on a 3D printer.

Air conditioners are quite strong, you can find cars with original compressors. But the weak condenser and tubes are usually replaced more than once, if the car is operated on the highway or under the hood of a strongly vibrating diesel engine.

Breakdowns of automatic climate-control mainly happen because of powerful stepper drive motors and breakage of gear wheels of the gearmotor. The motor can even break the splines and the damper itself, especially if you often make calibration. Well, the rod of the stepper motor eventually gets out of mesh with the gear reducer gears, you need to “knock” it into place. Sometimes it breaks the gears themselves, but it is rare. Of unpleasant moments: it is extremely difficult to remove the gear motor from the driver’s side, you will have to buy a bunch of gimbals and adapters, and at the same time take off the dashboard.


As we have already mentioned, in terms of electronics, the modifications of Peugeot 406 can be divided into three groups. The first one is the cars till ’99 with the classical comfort blocks and the BSM block. The second group includes cars after restyling and until the middle of 2001, with BSM and non-multiplexed block BSI (about the differences – below). And the third is with BSM and multiplex BSI.

Block BSM – this is originally under the hood unit relays and fuses, in later versions it is not just a switching element, but also has in its composition power control logic, tied to a block of BSI. But the block BSI in turn is an intelligent development of the “comfort unit”, which was responsible for switching all the circuits associated with the work of the elements of the cabin and safety. Blocks BSI has on board the processor and memory, and are programmed to interact with the various electronic systems of the car, while directly in the BSI is the logic of the anti-theft system and all programmable functions.

The cars before ’99 are the simplest, and their main problems are trivial. Alternators wear and tear, wiring and dashboard failures, interior harness failure and connectors in the driver’s legs and under the seat due to water and leaky wiring. These cars are the oldest, but not the most problematic.

The BSM unit has almost the same problems as the younger cars: oxidation of contacts and non-replaceable relays, which are hard to replace. Generators for reliability are about the same everywhere, it depends on the package and the motor. If you have Magneti Marelli, then wait for trouble, there is bearing wear, and the brush unit is capricious, it does not like dust and moisture, and the voltage regulator is an expendable item. If it is Siemens or Bosch, you just need to change the brushes every 150-200 thousand CZK and monitor the voltage regulator, which fails from time to time.

Many troubles are caused by failure of radiator fans both because of trivial wear and tear, and because of burning connectors of wiring and failure of regulator. The central locking unit behind the glove compartment fails very often. Smaller problems include failure of the outside temperature sensor, under-hood wiring breakdowns, connectors, window control unit breakdowns, control lever stub on the light switch, failure of the first mileage symbol on the odometer when over 300k mileage, and the like, which “does not affect speed”.

Cars after a restyling get an advanced comfort block, which now can be considered intelligent, and at the same time – a bunch of failures on all elements exactly because of problems with the BSI block. There is inability to turn on the lights, and the failure of wipers, and malfunctions of the dashboard, and breakdowns immobilizer system, and flying keys. All the old problems listed above don’t disappear, their set is almost the same.

A major change occurs only in mid-2001. The transition of BSI unit to a multiplexed bus VAN (Vehicle Area Network) to work with the unit BSM, steering wheel switch, dashboard, airbag unit, rain sensors, climate and multimedia systems, door modules, navigation, parktronic and other elements has greatly simplified the wiring. On the CAN bus now not only the engine control unit, but also ABS, automatic transmission control unit, control units for xenon, active suspension shock absorbers, etc. The amount of wiring has been reduced and its resistance to damage has been significantly increased.

But the car became even more dependent on the BSI unit, and the number of failures in it at first turned out to be unacceptably large. However, most of them with faultless and non-filled BSI board and serviceable BSM were accidental, and now serious software errors, because of which previously had to change the unit, are solved by flashing the module or some of its chips, the restoration of tracks or replacement of burned out elements. In addition, the once glitchy software has long been updated and deprived of “child’s illnesses”. As a result, now the latest 406 in terms of electrics can be recognized the least problematic of all.

Intermediate result

As you see, there are not so many congenital problems with the 406. The body is relatively strong, the interior is finished decently, and only in terms of electrics, surprises are possible, especially if we are talking about the cars of the turn of the century – 1999-2001. In the next part we will tell about the problems of the running gear, engines and transmissions of the 406.

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