Work on the TF105 began shortly before the conclusion of the 2004 season, with particular attention paid to the engine, which under revised FIA regulations was required to last across two consecutive race weekends. The car's design was supervised by Technical Director Mike Gascoyne, while Gustav Brunner oversaw the chassis design and Luca Marmorini led the engine programme. Many elements of the car were entirely new compared to its predecessor.
The season opened with a remarkable burst of pace. Jarno Trulli qualified second in the first race and continued to lead Toyota's charge through the opening rounds. In Malaysia, Trulli finished second, and in Bahrain he again took second place — giving Toyota their first podium finishes in the World Championship. After three races, both Trulli and Toyota were second in their respective championship standings, behind Fernando Alonso and Renault. In Spain, Trulli added another podium.
The United States Grand Prix at Indianapolis produced a controversial episode. Trulli had qualified on pole position for Toyota, but following a practice accident on Friday in which Ralf Schumacher suffered a tyre failure, Michelin expressed concern about the safety of its compounds on the banked Turn 13 and asked its client teams not to race, or to modify their setups to manage risk. When an agreement could not be reached on the use of a chicane, the six Michelin-shod teams — including both Toyotas — withdrew from the race after the formation lap. Trulli was unable to benefit from his pole. Ricardo Zonta had substituted for the injured Ralf Schumacher, as Schumacher was ruled out entirely following his Friday shunt.
Ralf Schumacher contributed meaningfully to Toyota's season in the second half of the year. He took third place at the Hungarian Grand Prix and set the fastest lap at the Belgian Grand Prix, both firsts for the team. The TF105 was strongest at medium-to-high-speed circuits where its aerodynamic efficiency could be exploited.
Toyota developed a B-specification variant of the TF105 intended for introduction from the Italian Grand Prix onwards. Problems in development testing delayed its arrival; the TF105B only appeared at Suzuka for the Japanese Grand Prix. A notable technical feature of the B version was the absence of a keel, with the front suspension mounted higher on the car. The revised package suited Ralf Schumacher in particular: on the car's debut at Suzuka, drawing on his familiarity with the circuit from his Formula Nippon career, he took pole position. The TF105B scored 7 points in total across its limited outings, including a podium at the 2005 Chinese Grand Prix.
Alongside the race programme, Toyota used a modified version of the TF105 chassis as a development mule for the RVX-06 V8 engine that would power the following year's TF106. Adapted to accommodate the new engine configuration, the car was designated TF105.5 and driven by French test driver Olivier Panis. Panis reported that the new V8 was approximately 2.5 seconds per lap slower than the V10 unit used in the TF105 during the 2005 season.
The TF105 achieved a measure of popular fame beyond the racing world when one was used on the British motoring programme Top Gear to set an indoor speed record at the ExCeL Exhibition Centre in London. With Jarno Trulli wearing the show's signature "Stig" helmet at Toyota's insistence that no non-Toyota driver operate the car, a speed of 81 miles per hour was recorded — limited by the polished floor surface and available run-off distance.
The TF105 remains Toyota's benchmark Formula One car, the single season in which the manufacturer's enormous investment in the sport produced results befitting a top-four constructor. The combination of Trulli's early-season pace, the car's aerodynamic competence, and the upgraded TF105B package made 2005 Toyota's most credible campaign before the team withdrew from Formula One at the end of 2009 without having won a race.