Communication with scan tool MB991958 is impossible
Immobilizer-ECU is energized when the ignition switch is turned "ON," and the MFI relay is turned on. The ECM < M/T > or PCM < A/T > transmits a signal from scan tool MB991958 to the immobilizer-ECU as it is. In the same way, a signal from the immobilizer-ECU is also transmitted to scan tool MB991958 as it is.