Operation CHARM: Car repair manuals for everyone.

Oscilloscope Patterns and Waveforms






Comparison Images EWS Oscilloscope Measurement

IMPORTANT: During the measurement, the DME/DDE must be connected.


Waveform:






Fig. 1: Signal OK.

Bear in mind that the statement "OK" only refers to the data line and the signal form. It is unable to determine whether the transmitted code is correct.


Waveform:






Fig. 2: Signal NOT OK.

The above signal indicates a fault in the DME/DDE.


Scope Reading:






Fig. 3: Signal NOT OK

The above signal indicates that the electronic vehicle immobilizer is not isolated or that there is a short to positive.


Scope Reading:






Fig. 4: Signal NOT OK

The above signal indicates a short circuit to ground or an open circuit.