Citroën DS4
The EP6 VTi (N12/EP6C) is the naturally aspirated variant of the Prince engine without direct injection, making it less susceptible to intake valve carbon build-up than the THP. The early production chain tensioner issue is known; PSA improved the tensioner from 2012. Regular oil changes every 10,000 km are mandatory.
Lifestyle compact
120 hp VTi in the DS4 — enough for everyday use; the DS4 is not sporting with it. The styling promises more than the engine delivers.
Engine Weaknesses 6
Early EP6 VTi engines (pre-2012) suffer from a weak hydraulic chain tensioner that rattles on cold starts. The single-row timing chain stretches when tensioner pressure drops, causing valve timing to shift. PSA documented oil leaks from the chain tensioner between April 2010 and April 2011.
Symptoms: Rattling or chattering from the timing chain area for several seconds after cold start, occasionally also at operating temperature when oil level is low
The hydraulic chain tensioner on the EP6 VTi is a known weakness at PSA and BMW. The tensioner loses oil pressure when stationary, causing the chain to rattle on cold start and risk jumping a tooth.
Symptoms: Loud rattling on cold start that disappears after a few seconds, engine check light, camshaft position sensor fault code
The oil separator (PCV diaphragm) in the EP6 valve cover tears and routes unfiltered oil into the intake tract. This leads to elevated oil consumption, coking of the intake valves and visible oil in the intake hose.
Symptoms: Elevated oil consumption without visible external leak, oil in intake hose, blue smoke after cold start, power loss from contaminated intake valves
The EP6 VTi exhaust valves in particular suffer from premature valve stem seal wear. Oil sprays into the combustion chamber and forms carbon deposits on the valve faces, progressively reducing engine efficiency.
Symptoms: Blue smoke on cold start or during overrun, high oil consumption above 0.5 l/1,000 km, black deposits on spark plugs
The thermostat housing with integrated sensor on the EP6 VTi has design weaknesses. For older C3 production years up to end of 2013 Citroën officially issued a fix via an additional temperature sensor.
Symptoms: Slight coolant smell, falling coolant level, temperature gauge fluctuates, occasional overheating warning
The solenoids for variable camshaft timing (VVT) on the EP6 VTi wear over time and eventually produce fault codes P0014 or P0016. Replacement is inexpensive but is often ignored for too long.
Symptoms: Power loss especially in the mid rev range, rough running, engine check light, fault codes P0014 or P0016
Vehicle Weaknesses 4
The electric power steering in the DS4 I can fail — the steering servo motor gives up, making the steering extremely heavy. Causes are typically ECU faults or defective connectors at the column motor.
The central BSI control unit in the DS4 I is prone to software faults that simultaneously trigger warning lights for ABS, ESP, ASR and the parking brake. The cause is often moisture in connectors or a weak 12V battery.
Corrosion at the ABS sensor wheel bearing seats causes the sensors to seize and become impossible to remove. The underfloor can also rust broadly on neglected vehicles.
Brake discs on the DS4 I wear above average, especially in urban use. Surface rust after extended standstill causes loud squealing on the first braking application. Front discs are more severely affected.
