2009 Daihatsu Sirion 1.0L Petrol · YX09 WMP

UK road salt and damp climate cause severe corrosion along the inner sills, rear chassis legs, jacking points, and front subframe mounting brackets. The factory electro-coating and underbody sealant degrade over time, allowing moisture to penetrate sheet metal joints. If neglected, corrosion weakens structural rigidity and mounting points for the suspension and powertrain, resulting in MOT failure. Remedial repairs require cutting out degraded metal and welding replacement structural repair panels.

Second-generation M300 Sirion models use an electric power-assisted steering (EPAS) column assembly with an integrated torque sensor and assist motor. Internal sensor drift, solder joint fatigue, or motor brush wear causes intermittent steering assistance loss, uneven weighting between left and right turns, or sudden shutdown while parking. In many cases, the EPS warning light illuminates on the dashboard. Because the sensor is integrated into the column, replacement of the complete steering column unit is typically required.

Frequent traversal of speed humps and potholed British tarmac causes accelerated wear to the rubber bushes in the front lower control arms and the ball-joints of the anti-roll bar drop links. The bonded rubber splits and perishes, leading to excessive suspension play, imprecise steering tracking, and clunking over uneven road surfaces. Degraded drop links and split ball-joint rubber dust gaiters are leading causes of UK MOT advisories and failure points on high-mileage Sirions.