Output Diagnostic Test Mode (DTM)

Output Diagnostic Test Mode (DTM)

NOTE:
- This Repair Information only outlines the function "output Diagnostic Test Mode (DTM)". Perform the function "output Diagnostic Test Mode (DTM)" in Guided Fault Finding, here is also found corresponding notes on the function of various components during output DTM. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
- Note the following as regards final control diagnosis:
- The request to activate the coolant fan (0 to 100%) is sent by the Climatronic Control Module J255 to the respective Engine Control Module (ECM). Fan is however only switched on by engine control unit when engine is running. Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
- Final control diagnosis can only be implemented at vehicle speeds below 5 km/h.
- Final control diagnosis can be repeated several times if necessary.
- Control element malfunctions are stored in fault memory.
- During output Diagnostic Test Mode (DTM), A/C system controls and display of the Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) are switched off. Only during the "Segment test" function are the display segments of the, Climatronic Control Module J255 (Rear A/C Control Head (Climatronic) E265) are actuated.
- The A/C system control motors are driven into a pre-determined position by the, Climatronic Control Module J255, (Rear A/C Control Head (Climatronic) E265) after selecting the "output Diagnostic Test Mode (DTM)" function. During final control diagnosis, it is therefore not necessary to wait for control motors to reach a specified position.