In this work, we propose a low cost spectral power extraction technique to observe the output spectrum of the frequency synthesizer and perform the IIP3 (input third-order intercept point) test on the RF receiver. The underlying idea is to configure the RF receiver as an analog spectrum analyzer to test itself--the transceiver faults such as spurs and non-linearity appear in the observed frequency spectrum as abnormal components. Using readily available on-chip resources, strength of the spectral components is converted to a DC-like low frequency signal which can be measured with simple instrumental assistance. Thus, interpretation of the measurements is straightforward and the results are directly mapped to the system specifications, which also reduces the diagnosis complexity. A Bluetooth transceiver is used as the vehicle to validate the proposed technique. Simulation results show that the frequency synthesizer?s spurs are clearly identified and IIP3 measured with less than 1 dBm error.