Output Diagnostic Test Mode (DTM) (Function 03)

Output Diagnostic Test Mode (DTM) Procedure












- On vehicles with A/C Compressor Regulator Valve -N280- there also an Evaporator Vent Temperature Sensor -G263 installed. The A/C Control Head -E87- uses the measuring value of the Evaporator Vent Temperature Sensor -G263- to control the temperature of the evaporator via the A/C Compressor Regulator Valve -N280-.
- The actuator "A/C Compressor Regulator Valve -N280" or "A/C clutch -N25" is only actuated with engine switched off These actuators will not be displayed on the VAS 5051 display and not activated by the A/C control head -E87- with the engine running.
- The A/C Compressor Regulator Valve is installed in the compressor (the compressor can only replaced by a work shop that is authorized for air conditioning work).
- The current that flows through the "switched on" control valve can be measured using the current pick-up clamp See electrical testing.
If another compressor cut-off condition exists besides "5 = engine speed less than 300 RPM" the "A/C Compressor Regulator Valve -N280-" or "A/C clutch -N25-" is not activated.




































































NOTE:
The output DTM only activates the heated front windshield if the passenger compartment temperature is less than 40 °C. If the temperature is higher, the text "Function unknown or cannot be carried out" is displayed on scan tool.
- The switch on function of Heated Windshield Control Module -J505- can be checked using VAG 1715 multimeter. Place current pick up clamp across B+ wire from Heated Windshield Control Module -J505- and heated front windshield and select multimeter function to "Current measurement with current pick up clamp". The display will change from approx. 0 amps to greater than 7 amps.
- Function of heated front windshield (Read measuring value block on vehicles from model year 2002, display group 016)