Bosch 04L130277AC Diesel Injector

On the 2.0L TDI platform, a failing Bosch 04L130277AC injector typically presents as: unstable idle or shaking at idle; loss of power, poor acceleration or limp mode; diesel knock or metallic rattling, especially cold or under load; white or black smoke; hard starting; fuel smell or a rising oil level in advanced cases.

When two or more of these appear together, suspect the injector before peripheral systems — a comparative leak-off test and live-data cylinder-balance review will isolate the failed unit without tear-down.

The documented failure modes on this platform are: injector delivery drift showing as deviation values out of range; injector electrical faults logging cylinder circuit codes; leaking or stuck-open injector diluting the engine oil with diesel.

Internal wear cannot be repaired in situ — once delivery drifts outside calibration, remanufacture or replacement is the reliable fix.

Log injector correction values in diagnostic software — a large outlier identifies the weak unit. Check the engine oil for diesel dilution on suspected leaking injectors. EGR, DPF and fuel-pressure faults overlap with injector symptoms on the EA288 — confirm with leak-back and live rail-pressure data. Injector coding is required after fitting — follow the manufacturer procedure.

Never condemn a common-rail injector on a fault code alone — codes identify the circuit or cylinder, while leak-off volumes and correction values identify the component.

Each remanufactured 04L130277AC is fully stripped, ultrasonically cleaned and inspected; worn components are replaced with OE-grade parts. The rebuilt unit is then calibrated on a common-rail test bench against the manufacturer's specification sheet — delivery, back-leak and response are all verified before the injector is sealed and despatched with its calibration data on file.

Every unit carries a 12-month parts warranty and free UK delivery.

The 04L130277AC trusted family covers 9 verified vehicle fitments across 4 makes: Audi, Seat, Skoda and Volkswagen. Every fitment listed on this page is registry-verified — no scraped or assumed applications.

04L130277AC supersedes or cross-references 4 further OE numbers, including 04L130277AT, 04L130277F, 0445110611 and 0445110612. Always match the reference etched on your failed unit's body — cross-references within a family are verified equivalents, but etched numbers remain the source of truth.