Method for encoding/decoding a signal at a first and second communication node (N1; N2) in a road vehicle. A signal (1) from an on-board sensor (10) is encoded using a first encoding scheme (a), encoding the formed single encoded sensor signal (1a) using a second encoding scheme (b), decoding this double encoded sensor signal (1ab) in the second communication node (N2) based on the second encoding scheme (b), forming a decoded single encoded sensor signal (1a′). In the first communication node (N2), performing a comparison analysis, comprising at least one of the following: comparing the decoded single encoded sensor signal (1a′) with a stored single encoded sensor signal (1a), or after encoding the decoded single encoded sensor signal (1a′) with the second encoding scheme (b) comparing (110) the thus formed double encoded sensor signal (1a′b) with a stored double encoded sensor signal (1ab). If the compared sensor signals (1a′,1a; 1 ab,1a′b) match, then sending (111) a signal to the second communication node (N2) validating the sensor signal (1), and if they do not match, then initiating (112) a corrective action.