Audi introduced a redesigned Audi A4 in late 2004, now riding on the B7 platform, which is completely unique to Audi and not shared with Volkswagen. Nonetheless, the B7 is really a revision of the outgoing Audi A4 B6, and not a ground-up redesign. This is confirmed by Audi's internal platform nomenclature, which uses PL46 (longitudinal passenger car platform, size 4, generation 6) for both Audi A4 B6 and B7 chassis.
The engine lineup received many additions, the most notable of which was the introduction of Fuel Stratified Injection on the new 2.0 TFSI and 3.2 V6 FSI, respectively capable of 200 and 255 PS (147 and 188 kW), although these engines dropped the five-valve design in favor of the more widely known four valves per cylinder configuration, as the design was incompatible with the direct injection system. The new 2.0 TDI engine now combined Pumpe Düse (PD) technology with 16 valves for the first time, while the larger 2.5 TDI was increased to 3.0 L, with 204 PS (150 kW). quattro was available either as an option or standard on most mid- to high-end models, with multitronic and Tiptronic automatic gearboxes available throughout the entire lineup. As per the Audi A4 B6, multitronic is available only on front-wheel drive models and Tiptronic only available on quattro models.
In addition to the carry-over S4, which remained unchanged on the technical side, Audi has reintroduced the RS4 to the lineup, for the first time on the sedan body and with a normally aspirated 4.2 V8 FSI engine. Another notable inclusion is the 3rd-generation quattro system which uses 40:60 front-rear power distribution. A limited edition variant first introduced in late 2005, named "DTM Edition", was reintroduced in 2006 as a regular option, the 2.0T FSI engine now engineered to 220 PS (162 kW) with standard quattro. The front grill assembly has changed to be full height in the same manner as the Audi A6.
The Audi A4 B7 Cabriolet model arrived later than the other two body variants, with sales beginning in February 2006. Brand new on the Cabriolet was an entry-level 2.0 TDI version, but to date this is not being offered with the Multitronic gearbox.
