Selected mapping (SLM) based schemes effectively reduce the peak-to-average power ratio (PAPR) of orthogonal frequency division multiplexing (OFDM) systems. However, they require side information (SI) transmission, which incurs a loss in the data throughput in addition to the increased system complexity. This paper presents a blind SLM scheme based on a decision metric obtained from pilot sub-channel responses. A novel SI detection method enabling low complexity data decoding is proposed. The SI is detected by exploiting the high autocorrelation between adjacent pilot sub-channel responses. The SI detection error rate is analytically derived and compared with that obtained by simulations. Simulation results of the data decoding scheme based on the proposed SI detection method show the bit error rate performance comparable to that of the simplified maximum likelihood (ML) data decoding scheme, while the computational complexity is close to that of the embedded SI based decoding scheme.