The Volkswagen Group A platform is an automobile platform shared among compact and mid-size cars of the Volkswagen Group. It debuted in 1974 and was originally based on the engineering concept of the Volkswagen Golf Mk1, and is applicable to either front- or four-wheel drive vehicles, using only front-mounted transverse engines. Volkswagens based on this platform have been colloquially referred to by generation number, e.g. the first Golf version is referred to as an "A1 Golf". Often each generation is designated by substituting "Mark" for "A", but this can be misleading. For example, the Mk1 and Mk2 Scirocco are both based on the A1 platform. Furthermore, confusion was possible with the Volkswagen Passat, which has been produced on both the B platform alongside the Audi A4, as well as the A platform depending on the generation. Volkswagen Group introduced a new alphanumeric nomenclature for vehicle platforms for the fourth generation. Under Volkswagen's revised platform naming system, the "A4" platform became the PQ34 platform, and what would have been called the A5 platform was called the PQ35 platform. The platform code is composed as follows: A letter, P, indicating a passenger car platform A letter indicating the configuration of the engine: Q indicates a transverse engine (Quer in German) A digit indicating the platform size or class: 3 corresponds to compact cars 4 corresponds to mid-size cars A digit indicating the generation or evolution The A platform has been superseded by the MQB platform for new models, with the exception of a few models only sold in certain markets. A1 The A1 platform debuted on the Mk1 Golf on its launch in 1974, and continued into the early 1990s, when the last remaining models using the platform - the Scirocco and Caddy - were discontinued. A1 platform cars (Typ numbers in brackets): Volkswagen Golf Mk1 (17) Volkswagen Golf Cabriolet (155) Volkswagen Jetta Mk1 (16) Volkswagen Caddy Mk1 (14) Volkswagen Scirocco Mk1 & Mk2 (53/53B) Volkswagen Citi Golf A2 The A2 platform debuted in 1983 on the Mk2 Golf, and lasted until 1998, when the original SEAT Toledo (the first Volkswagen-developed SEAT following the Spanish company's takeover by Volkswagen) was replaced. The Volkswagen Passat B3 was based on a stretched A2 platform. The Volkswagen Corrado, while being an A2 platform car, uses some components from the A3 platform, notably the rear suspension assembly and some front suspension parts. A2 platform cars (Typ