Omega B
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Checking the Cruise Control for Diesel Engines (DDE 2.1)
Features Specific to this System
The Digital Diesel Electronics DDE 2.1 is equipped with self-diagnosis. This means:
If the DDE 2.1 control unit recognizes a fault in the system, it is stored after a certain period of time. If the fault is serious, the engine telltale is activated; if the fault could lead to uncontrolled engine running or engine damage, the engine is switched off via the injection amount regulation.
Important: All fault memories are deleted when the battery is disconnected from the vehicle electrical system.
The trouble codes in the Digital Diesel Electronics DDE 2.1 can be deleted using TECH 1. If trouble codes with the status "present" are stored, trouble codes with the status "not present" can only be completely deleted by switching the ignition off and on again once after deleting. If the ignition is not switched on and off, only the most recently stored trouble code with the status "not present" can be deleted.
In some respects, this system behaves differently from the other familiar engine management systems when storing trouble codes:
· In vehicles without control switch S43, trouble code 92 is always stored with the status "present"; there is no fault in the system, but control switch S43 is not installed. If, however, trouble code 91 is stored, trouble-shooting should be performed (see data list parameter no. 17).
· In theory, the trouble codes "short circuit to ground" and "short circuit to voltage or circuit interruption" cannot occur together in component groups which share a common function. As both of these trouble codes are not automatically reset after a malfunction (a peculiarity of this system), both trouble codes remain stored. Treat both fault cases as specified in the F0:DATA LIST.
Note: The snapshot mode (key F3) cannot be activated for detecting sporadic faults (e.g. loose contacts) in this system.
Input variables which specify a test condition of "vehicle travelling at ...km/ h (mph)" must be tested exactly as stated, as otherwise any statements about the functionality of the DDE 2.1 system will not be precise enough.
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