Initiating Output DTM
Output Diagnostic Test Mode (DTM) (function 03)
Note the following as regards Output Diagnostic Test Mode (DTM) diagnosis
- The A/C Compressor Regulator Valve N280 is only activated by the operating and display module, Climatronic Control Module J255 with the engine stopped.
- The request for activation of the Coolant fan (speed "1" and speed "2") is always transmitted by the operating and display module, Climatronic Control Module J255 to the relevant engine control module. However, the engine control module only switches on the fan(s) if the engine is running "Guided Fault-Finding" Vehicle Diagnosis, Testing Info. System VAS5051B or Vehicle Diagnosis Service Syst. VAS5052.
- Output Diagnostic Test Mode (DTM) diagnosis can only be implemented up to an engine speed of 3000 RPM and at vehicle speeds below 5 km/h.
- For install locations of components activated.
- If necessary, Output Diagnostic Test Mode (DTM) diagnosis can be repeated several times.
- Control element malfunctions are stored in the DTC memory.
- Control action and the display of the operating and display module, Climatronic Control Module J255 are deactivated during Output Diagnostic Test Mode (DTM) diagnosis (depending on version, 22 degrees C appears for example in both displays). The "segment test" function is the only function during which the display segments of the operating and display module, Climatronic Control Module J255 are activated.
- The air conditioner control motors are moved into a predetermined position by the operating and display module, Climatronic Control Module J255 after selecting the "Output Diagnostic Test Mode (DTM) diagnosis" function. During Output Diagnostic Test Mode (DTM) diagnosis, it is therefore not necessary to wait for the control motors to reach a specified position.
NOTE: On vehicles with 8-cyl. engine, the compressor is not driven via a belt, but rather by way of a shaft.
Initiating Output DTM
- With the ignition switched off, connect Diagnostic Operation System VAS 5051A using, for example, Diagnostic Cable - 3 Meter VAS 5051/5Aand K-Lead Adapter Vas6017B VAS 6017B (or K-Lead Adapter VAS 6017A) to the 16-pin diagnostic socket in the vehicle. Diagnostic Operation System VAS 5051A, Connecting and Selecting Functions
- Switch on ignition/start engine.
NOTE:
- Switch on ignition (engine not running, for checking activation of A/C Compressor Regulator Valve N280).
- Start engine (to check activation of Coolant Fan V7).
- Set "Auto" mode on the operating and display module, Climatronic Control Module J255.
- Use address word "08" to select A/C heater electronics. VAS 5051A Scan Tool (ST), Connecting and Selecting Functions
- Open instrument panel vents.
- Check DTC memory of operating and display module, Climatronic Control Module J255. Displaying & Reading Trouble Codes
Indicated on display of Diagnostic Operation System VAS 5051A :
- Select function "03 - Output Diagnostic Test Mode (DTM) diagnosis".
Indicated on display of Diagnostic Operation System VAS 5051A :
- Display field -1 - shows which control element is currently being activated (e.g. 1st control element in test).
- Display field - 2 - gives a consecutive list of control elements already activated and the one currently being activated. The one currently being activated appears in the bottom line.
- Touch -> key to select next component. Function and sequence Activated Actuators
NOTE:
- Touch <- key to return to selection program.
- Output Diagnostic Test Mode (DTM) diagnosis can be terminated by pressing C key.
- On completion of Output Diagnostic Test Mode (DTM) diagnosis, check DTC memory. Displaying & Reading Trouble Codes
- If Output Diagnostic Test Mode (DTM) diagnosis is aborted, check DTC memory and read measuring value block (display group "002").
Displaying & Reading Trouble Codes
Measuring Value Blocks (Function 08)