Citroën DS5

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 6-speed EAT6 automatic in the DS5 I is particularly prone to faults in solenoid valves and the gearbox oil pump between 60,000 and 100,000 km. Jerky shifts, delayed kickdown and gearbox fault codes follow.

Control arm bushes and ball joints on the DS5 I front axle need replacing at least once during the vehicle's life on many cars. Noises over crosswise expansion joints and uneven tyre wear are typical signs.

The MyWay infotainment system in the DS5 I is prone to freezing, spontaneous reboots and screen blackouts while driving. The navigation system stops working reliably after a system crash. Software updates only partially help.

The climate control ECU in the DS5 I develops faults over time. Temperature sensors and blower motors fail, causing the climate system to regulate incorrectly. The A/C compressor shows declining output from 100,000 km.

The DS5 I shows rust at sills and wheel arch edges, especially on early build years without regular cavity sealing. Stone chip damage on the bonnet accelerates corrosion.