Not sure what 135 is but the Engine speed input signal dubious sounds like Nanocom code 21-6 &/or 21-7
For info The TD5 ECU does not monitor fuel flow, or fuel pressure, so it cannot detect fuel starvation issues. Was it does notice though is that the engine RPM or road speed is not where it expects it to be for the selected throttle position & Logs a fault.
The road speed input signal is supplied by the ABS / SLABS ECU (if fitted) or else by the gearbox via a reed switch. Failure of this input should disable cruise control. Does yours work (if fitted)?
So a problem with the ABS system and/or a problem with the driver input (accelerator/fuel/air).
HTH
Chan