Common Problems with the
2003 Peugeot 406

The 2.0 HDi 110 and 2.2 HDi models utilize a dual mass flywheel (DMF) to dampen diesel crankshaft torsional vibrations. Over higher mileages, the internal springs and friction damper mechanisms within the flywheel fatigue and break down. This results in heavy driveline shudder, metallic chattering at idle, clutch slip in higher gears under torque, and in severe cases, catastrophic flywheel separation that punches through the gearbox bellhousing.

The 406 features an advanced multi-link rear suspension design with trailing arms, transverse links, and passive rear-steering tie rods. After years on potholed UK roads, the rubber bonded bushes on the rear transverse track control arms and passive steer links perish and develop significant play. This causes vague rear-end handling, wandering or twitchiness on motorways, severe scrubbing of the rear tyres, and recurring MOT failures.

On Phase 2 models equipped with the multiplexed digital architecture, the steering column switch cluster (COM2000 unit) integrates the indicator, lighting, and wiper stalks into a single electronic module. The internal plastic detent springs and ribbon cables wear out over time. Common symptoms include an indicator stalk that drops under gravity and indicates left after completing a right turn, headlights switching on and off unprompted, or the horn failing to sound.