Citroen C5 Q4BA Injectors

Citroen C5 Q4BA Overview

The Citroen C5 with the Q4BA 2.2L HDi / TDCi engine was produced between 2006 and 2012. This vehicle uses Bosch common rail diesel injectors (primary part number 0445115025) operating at fuel pressures up to 2000 bar. The Q4BA engine in the Citroen C5 produces and of torque. When replacing injectors on the Citroen C5 Q4BA, always use new copper sealing washers and torque to manufacturer specifications. Each injector should be coded to the ECU after fitting.

Compatible Injectors

Common Injector Problems in Citroen C5

• •
  Rough idle and engine vibration — Worn injector nozzles cause uneven fuel spray, leading to rough idle at low RPM. Most noticeable when the engine is cold.
• •
  Excessive exhaust smoke — Black or blue-grey smoke on acceleration indicates poor fuel atomisation. This is often caused by carbon buildup on the injector nozzle tip.
• •
  Poor fuel economy — A worn or leaking injector delivers incorrect fuel quantities, reducing efficiency by 10–20% in severe cases.
• •
  Engine misfire under load — Intermittent misfires during acceleration suggest one or more injectors are failing to deliver the correct fuel pressure.
• •
  Difficult cold starting — Degraded injector nozzles struggle to atomise fuel at lower cranking pressures, causing extended crank times in cold weather.

Other Engine Codes for Citroen C5

Other Q4BA Vehicles

Related Pages

Bosch 2.2L HDi / TDCi — browse compatible engines, vehicles, and injectors