SEAT

SEAT Gearboxes and Engines: pre- and post-2010 faults are a different story

On SEAT models from 1998 to 2008, the most common warning signs affect the 5-speed manual gearbox and first-generation TDI engines. The 1.9 TDI — found on the Ibiza, Leon and Toledo with engine codes such as AGR, ALH, ARL, ASZ — is well known for clogged EGR valve leaks and drifting injectors, resulting in rough idling and excessive fuel consumption. The associated 5-speed manual gearboxes suffer from a stiff 2nd-gear change and premature differential wear at high mileages. The 1.8 T 20V (engine codes AGU, AJQ, APP, AQA, AUM, AUQ) has a well-documented tendency for piston ring fouling when oil changes are left too long, with abnormal oil consumption as the tell-tale symptom.

Post-2010: DSG 7 and new-generation TDI engines, new symptoms

The Leon II and Leon III brought widespread adoption of the DSG 7 and 2.0 TDI common-rail engines, covering an extensive range of engine codes — CAGA, CBDA, CFHB, CUNA, CUPA, DFFA, DFGA among others — spanning outputs from 110 to 184 hp. On these generations, vibrations below 30 km/h and juddering in urban driving often point to a mechatronic unit fault on the DSG 7: the gearbox listed here is sold without the mechatronic unit but includes a new dual-clutch. The 1.6 TDI (CAYB, CAYC, CLHA, CRKB, DBKA in particular) appeared on the Ibiza and Leon from 2009 onwards; it is known for dual-mass flywheel issues and EGR-related soot build-up in the intake manifold, which frequently leads to the turbo being replaced at the same time — also available as a reconditioned unit on this page.

Finding your way around the SEAT collection

The Leon accounts for the majority of available references, followed by the Ibiza and the Altea. Gearboxes make up the largest family, ahead of bare engines and turbos. For Cupra versions — 1.8 T 180 hp (AJQ, APP, ARY, AUQ) or 2.0 TSI up to 310 hp (CJXA, CJXB, CJXC, CJXE, CYFB) — the parts are not interchangeable with those from standard versions of the same engine capacity: the engine code stamped on the block is the only reliable identifier. The EDEN BOITES collection covers model years 1998 to 2024, available on an exchange basis or as a rebuild of the customer's own unit, depending on the reference.