EWS oscilloscope measurement: Important

The DME/DDE must remain connected for the duration of the test-measurement routine. The CAS control unit should not be enabled. It transmits a continuous EWS immobilizer signal whenever Terminal 15 is hot.

Fig 1: CAS Control Unit Signal Waveform (OK)

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Please note that the "OK" assessment relates exclusively to the data wire and the signal shape. It cannot be determined whether the transmitted code is correct.

Fig 2: CAS Control Unit Signal Waveform (Not OK)

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

Fig 3: CAS Control Unit Fault Signal Waveform (Not OK)

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The above signal indicates a wire fault or a fault in the CAS.

Fig 4: Display - DSC Control Unit Speed Signal Screen (Not OK)

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The above signal indicates a short circuit to positive.

Fig 5: Display - EWS Vehicle Immobilizer Screen (Not OK)

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The above signal indicates a short circuit to earth or an open wire/circuit.

Fig 6: CAS Control Unit Signal Waveform (OK)

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Please note that the "OK" assessment relates exclusively to the data wire and the signal shape. It cannot be determined whether the transmitted code is correct.

Fig 7: CAS Control Unit Signal Waveform (Not OK)

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

Fig 8: Display - DSC Control Unit Speed Signal Screen (Not OK)

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The above signal indicates that the EWS vehicle immobilizer has not been enabled or that a short circuit to UBatt is present.

Fig 9: Display - EWS Vehicle Immobilizer Screen (Not OK)

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The above signal indicates a short circuit to earth or an open wire/circuit.

Fig 10: Display - DSC Control Unit Speed Signal Screen (OK)

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The speed signal from the DSC control unit must be a rectangular signal with amplitude Ubat.

Fig 11: Display - DSC Control Unit Speed Signal Screen (Not OK)

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The above illustration indicates a short circuit to earth.

Fig 12: Display - DSC Control Unit Speed Signal Screen (Not OK)

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The above illustration indicates an open wire or a problem related to the DSC.