Citroën C1
PSA entry-level diesel with common-rail injection. Economical and reliable, but low on power. Timing chain is maintenance-free.
Economy diesel in a city car
54 hp diesel in the C1 — extremely economical but also extremely slow. Just about acceptable for commuters who never use the motorway.
Engine Weaknesses 6
Injectors seize in their bores through heat and carbon deposits. Removal requires specialist tools; in severe cases of seizure a replacement cylinder head is often needed.
Symptoms: Smoking exhaust, power drop, diesel smell in engine bay, misfires
Soot particles and oil coke deposits clog the turbocharger oil strainer filter. Insufficient lubrication causes bearing failure. Excessively long oil change intervals (over 15,000 km) significantly aggravate the problem.
Symptoms: Whistling or rattling turbo noise, blue smoke, lack of power, oil loss
The EGR valve becomes heavily coated with soot from exhaust gas recirculation in urban driving. A blocked valve worsens engine running, increases fuel consumption and can damage the turbocharger through oil contamination.
Symptoms: Hesitation in part-load range, increased consumption, engine warning light, poor driveability
The DV4's additive FAP filter only regenerates from around 500 °C. These temperatures are not reached in urban driving; the filter clogs prematurely. The Eolia additive in the tank extends regeneration intervals but is no substitute for motorway driving.
Symptoms: Particulate filter warning, power drop, rising oil level from fuel entry during regeneration attempts
The electric actuator on the variable geometry turbocharger sticks due to soot deposits from the exhaust. Typical on short-trip use where sufficient burn-off does not occur. Engine enters limp mode.
Symptoms: Sudden power loss, engine warning light, vehicle in limp mode with severely restricted performance. Occasional whistling from the turbo.
Glow plugs on the 1.4 HDi corrode and break off during removal. Failure rate increases from around 150,000 km. Cold-start problems caused by defective or broken glow plugs are difficult to remedy.
Symptoms: Poor cold-start behaviour, engine hard to start at temperatures below 5°C, fault code P1351 (glow plug relay circuit).
Vehicle Weaknesses 6
5,496 vehicles from build years 2005–2009 were subject to a recall in which the throttle pedal did not reliably return to its resting position. This can cause unintended acceleration.
Brake discs on the C1 I wear out very early. The rejection rate at the first MOT is already three times higher than the class average. Brake lines also start to rust early.
The water pump on the C1 I can start leaking and losing coolant from around 50,000 km. Unnoticed loss risks engine overheating. Mainly affects models up to 2008.
From the second MOT inspection, rejection rates for the exhaust system due to rust rise sharply. The ADAC lists the exhaust as the main breakdown hotspot. Cracks in exhaust pipes and silencers are regular occurrences.
Headlights and rear lights are flagged above average at the MOT. Door locks tend to fail prematurely; the starter motor fails frequently on 2007–2009 build years.
Door seals distort with age and no longer seal properly. Quarterlight windows also close poorly, allowing moisture into the interior and encouraging mould.
