Citroën DS3

The THP engine suffered severely from timing chain stretch caused by the weak single-row tensioner, combined with camshaft sprockets slipping on the shaft. This leads to uncontrolled valve timing loss and can cause piston-to-valve contact. PSA improved the sprockets from model year 2012 onwards.

Symptoms: Rattle on start-up, power loss, rough idle, check engine light P0011/P0012, in the worst case engine damage without warning

THP engines frequently consume 1–3 litres of oil per 1,000 km from around 80,000 km, in extreme cases up to 4 l/1,000 km. Causes are worn exhaust valve stem seals and piston rings worn from soot deposits.

Symptoms: Very frequent oil top-ups, blue or white smoke from exhaust, black deposits on spark plugs, oil smell in engine bay

The THP turbocharger suffers from insufficient oil supply, especially when the oil level drops too low or the oil degrades from excessively long change intervals. Oil coke from the crankcase also blocks the oil feed line to the turbo.

Symptoms: Whistling or rattling turbo noise, blue smoke under full load, power drop, measurable boost pressure loss

The high-pressure fuel pump (HPFP) on the EP6 THP fails frequently and results in insufficient fuel rail pressure. The engine stumbles on cold start or under load. Part number 1920LL (THP 150) or 1920RT (THP 200).

Symptoms: Stumbling on cold start, fault code P0087 fuel pressure too low, power loss under full load, hesitant throttle response on acceleration

In the EP6 THP, a secondary chain drives the oil pump. This secondary chain wears and can break. The result is a drastic drop in oil pressure that causes immediate engine damage if the STOP warning is ignored.

Symptoms: Oil pressure warning light (STOP), pressure drop despite correct oil level, metallic noises, in the worst case engine shutdown

Direct injection without intake valve wash, combined with EGR recirculation, promotes soot deposits on the intake valves. In PHEV use with frequent electric driving, cold start condensation can make the problem worse.

Symptoms: Rough idle, starting difficulties when cold, engine stumbling, power loss

The wastegate control system on the EP6 THP is vacuum-operated with inverted logic. The solenoid valve for the vacuum supply fails frequently, leaving the wastegate open and preventing any boost pressure from building.

Symptoms: Vehicle only accelerates weakly as if naturally aspirated, maximum speed limited to 100–110 km/h, no turbo boost felt, fault code P0299

The German Federal Motor Transport Authority (KBA) issued a recall for the Citroën DS3 due to defective airbag inflators that can deploy uncontrollably and release metal fragments.

Electric window regulators are one of the most common failure points on the DS3 I. Cables snap or motors fail, typically from 60,000–80,000 km. The costly replacement module usually has to be replaced as a complete unit.

The DS3 I air conditioning compressor fails relatively frequently between 70,000–100,000 km. Leaking AC hoses and refrigerant loss are also known weak points. Repair requires compressor replacement and system recharge.

The DS3 I exhaust system corrodes heavily. TÜV reports and owner experience confirm above-average corrosion on exhaust pipes, clamps and joints, especially on vehicles used predominantly for short trips.

On the DS3 I, front control arm bushings and anti-roll bar rubbers wear faster than expected. TÜV defects and owner reports confirm above-average wear of the front suspension mounts.