Passenger car
In response to the changed Kei car regulations taking effect on January 1, 1976, Suzuki developed the T5A version for passenger car use. Passenger car engines were required to pass stricter emissions regulations than the LJ50, which was for commercial vehicles. The unrelated T4A engine was unable to meet these requirements and was also of only , so it was replaced in October 1977. The name refers to it being the first ("A") engine with a 0.5-litre displacement. From its it provided at 5000 rpm and at 3000 rpm. At the same time, this engine (with the same power specifics) was also fitted to the sporting looking Suzuki Cervo microcoupé. This could finally meet the tighter 1978 (53年) emissions standards, which the T4A had not been able to do. The emissions system was called "TC53", for Twin Catalyst, year 53 of the Showa era (1978 in the common era).