Output Diagnostic Test Mode (DTM) (Function 03)

Output Diagnostic Test Mode (DTM) - Function 03

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.
- For output Diagnostic Test Mode (DTM), make sure that the request to activate coolant fan (0 to 100%) is sent by front A/C control head Climatronic Control Module J255 to the respective Engine Control Module (ECM). Engine Control Module (ECM) switches on the fans but only with engine running Vehicle Diagnosis, Testing and Information System VAS 5051 in the "Guided Fault Finding" function (of A/C system and depending on engine fuel injection and ignition system).
- Output Diagnostic Test Mode (DTM) is possible only at a vehicle speed of less than 5 km/h.
- Component locations of activated components.
- The Output Diagnostic Test Mode (DTM) can be performed more than once if necessary.
- Malfunctions on the actuators are stored in the DTC memory.
- During output Diagnostic Test Mode (DTM), regulation of A/C system and displays of respective control module (of front Climatronic Control Module J255 of "Comfort" version) (and of Rear A/C Control Head (Climatronic) E265, if present) are switched off. Only during the "Segment test" function are the display segments of front Climatronic Control Module J255 (and of Rear A/C Control Head (Climatronic) E265) are actuated.
- The A/C system control motors are driven into a pre-determined position by the front operating and display unit, Climatronic Control Module J255 (and Rear A/C Control Head (Climatronic) E265) after selecting the "output Diagnostic Test Mode (DTM)" function. During the output Diagnostic Test Mode, it is not necessary to wait until the control motors have reached the pre-assigned position.

Initiating output DTM

- With ignition switched off, connect Vehicle Diagnosis, Testing and Information System VAS5051/5052 with Diagnostic Cable - 3 Meter VAS5051/5A to 16-pin Data Link Connector (DLC) in vehicle. Vehicle Diagnostic, Testing and Information System VAS5051/5052, Connecting and Selecting Functions
- Switch ignition on or start engine.
- Select the front Climatronic Control Module J255 via address word "08" or the Rear A/C Control Head (Climatronic) E265 via address word "28".

NOTE:
- Switch ignition on (when checking activation of A/C Compressor Regulator Valve N280, the engine should not be running)
- Start engine (to check activation of Coolant Fan V7)

- Check DTC memory of front Climatronic Control Module J255 (and of Rear A/C Control Head (Climatronic) E265) Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function. Check DTC Memory (Function 02)
- Switch on A/C system at front Climatronic Control Module J255 (and at Rear A/C Control Head (Climatronic) E265).
- Open vents in passenger compartment (in instrument panel, in center console and in "B" pillars and if necessary in "C" pillars).
- Select "03 - Output Diagnostic Test Mode (DTM)" function and perform DTM Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

NOTE:
- By touching the -> button you can call up the next component to be tested. Function and sequence of activated actuators.
- By clicking the <- button, you will return to the selection menu.
- Output DTM can be terminated e.g. by pressing the <- button.
- During output Diagnostic Test Mode (DTM), depending on control module version, measuring value block with the measured values applicable to the respective actuated component is displayed Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.
- After ending output Diagnostic Test Mode (DTM), check DTC memory Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
- When terminating output Diagnostic Test Mode (DTM), check DTC memory and read out measuring value block Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.