Printed wiring board (PWB) and printed circuit board assembly (PCBA) testing is part of the electronics production, which has a great impact on the profitability. Always high throughput and low cost testing is needed but for high quality and reliability. Bare board testing is vital before components loading. Defects after the PWB manufacturing process are possible such as opens, bridges, near-opens, near-bridges and characteristic impedance mismatches due to process variations and compounding raw material tolerances. Moreover, defects might cost about ten times when detected in the next test phase, another motivation for unpopulated board test is loading expensive components on a set of defective boards might be economically catastrophic. Flying probe systems, which were developed in late 1980’s, are commonly used and favorable to perform bare board isolation and continuity testing, especially when the volume is not big enough to justify bed of nails purchase. Flying probe system performance for a given bare board depends on the test algorithm, the mechanical speed and the number of probes. To reduce the cost on expensive test probes and probe maintenance and to accelerate the test time, this paper presents a new and cost efficient approach to test unpopulated and populated board with open sockets, using a single probe. Specifically, a coaxial probe injects one frequency signal into the PWB trace, the phase shift between the reflected signal from the trace and the incident wave is detected and compared with the nominal value, which has been captured from a defect free board, which already underwent direct continuity and isolation testing. By applying this test solution to bed-of-nails equipment, we will be reducing 50 % of the probes, on the other by employing this solution to flying probes system with two probes, for a given design with NI isolated traces and NA adjacent pairs we will be reducing the number of tests from (NI+NA) tests to NI tests as isolation and continuity are performed in one go. Flying probes system involves mechanical movements, which dominate the test time, by reducing the number of the mechanical movements we will be increasing dramatically the test throughput. The conducted experiments have shown a good feasibility for practical use in the Automatic Test Equipment (ATE) for PWB and PCBA testing. At the highest sensitivity of the phase shift detector, the prototyped tester is capable to distinguish between a defective and error free board with significant margins in case of defects such as opens, DC and RF bridges, exceeded and different width lines. The margin in the measurement between a defective and a correct board, which depends on the type of the defect, is about 7 % to 68 %. In case of loaded board testing, the approach is capable in detecting opens with important margins, our test cases shown 40 % and 33 %, which makes it a strong candidate approach to be applied officially to PCBA testing where probing is feasible. The approach can be applied to the complete layout or to boost the test strategy where the applied test solutions are not covering 100 % of the possible defects.