Reconditioned Citroën C4 Gearbox

BMP6 and manual gearboxes on the C4: two families, two distinct failure profiles

Across both generations of the Citroën C4, from 2004 to 2024, the gearbox is a component that frequently gives out before the engine. The BMP6 — a single-clutch automated manual gearbox — is the most common source of faults on this model: rough gear changes, refusal to engage a gear, and juddering in town. These symptoms affect the 1.6 HDi, the 2.0 HDi and the 2.0 petrol variants alike. The root cause is typically internal and mechanical, which makes partial repair impractical and generally leads to a full gearbox replacement. Please note: the BMP6 is sold without the robot unit or actuator — the external electromechanical assembly must be dealt with separately.

Manual gearboxes: the identification pitfalls between 5 and 6 speeds

Manual gearboxes cover the majority of the engine variants in this range, but they are not interchangeable between configurations. The 1.6 HDi can be fitted with either a 5-speed manual or a 6-speed manual depending on the year and engine code (9HX, 9HZ, 9HY, 9HP, 9HR, 8HX, 8HZ, 9HN). The 1.2 PureTech (codes EB2DT, EB2DTS) follows the same logic, with two possible ratios. The 1.6 THP (codes 5FV / EP6CDT or 5FX / EP6DT) and the 1.4 VTi 95 (8FP) are fitted exclusively with a 5-speed manual. On manual gearboxes, the most common symptoms are difficulty engaging first gear when cold, a grinding noise in reverse, or oil leaks from the output bearing — all signs of advanced wear that can quickly progress to synchromesh failure.

Choose by engine code, not just engine capacity

This range covers more than twenty distinct engine codes across a displacement span of 1.2 to 2.0. Two petrol variants both badged as '1.6' are in fact different blocks: the NFU / TU5JP4 (1587 cm³) and the 5FW EP6 (1598 cm³), each paired with a specific gearbox. Likewise, the codes RHR and RFN (EW10J4) / RFJ (EW10A) distinguish the variants of the 2.0 HDi and the 2.0 petrol. Identifying the engine code stamped on the block — rather than relying solely on the engine capacity shown on the registration document — is essential to selecting the correct gearbox for the C4.