TOKYO, Oct 31 (Reuters) - Denso Corp, Japan's largest auto parts maker, said on Thursday its first-half operating profit rose 17.4 percent, thanks to steady sales of air-conditioning systems and strong output by top shareholder Toyota Motor Corp .
Denso, 24.5 percent owned by Japan's largest automaker, said group operating profit totalled 80.10 billion yen ($651.5 million) for the six months that ended in September. Group revenues rose 4.9 percent to 1.14 trillion yen.
For the full year to March, the company slightly raised its net profit forecast to 146 billion yen from a May forecast of 145 billion yen. It also upped its full-year group revenue forecast to 2.24 trillion yen from 2.20 trillion yen.
Toyota, also Denso's biggest customer, reported on Wednesday its best-ever operating profit for any half year, driven by healthy North American sales, cost-cutting and a softer yen.
The announcement came after the close of morning trading on the Tokyo stock market. Shares of Denso rose 1.28 percent to 1,978 yen, compared with a 1.11 percent fall in the Nikkei average . ($1=122.93 Yen)