Output Diagnostic Test Mode (DTM) (Function 03)
Special Tools, Testers And Auxiliary Items:- VAG 1551/1552 Scan Tool using adaptor cable VAG 1551/3
- VAG 1598/18 Test Box
- VW 1594 adaptor kit
- Fluke 83 multimeter (or equivalent)
- VAG 1527B LED tester
Test Requirements For Vehicles With A/C:
- Vehicle at room temperature (warmer than +15°C)
- A/C system switched ON
- Select lowest temperature and highest blower speed
The Output Diagnostic Test Mode actuates the following components in the sequence given below:
1. Cold Start valve N108
2. EGR Vacuum Regulator Solenoid valve N18
3. A/C compressor interruption
4. Fuel cut-off valve N109
5. Wastegate Bypass Regulator valve N75
6. Glow plug relay J52
7. Glow plug indicator light K29
8. Relay for preheating coolant, low heat output J359
9. Relay for preheating coolant, high heat output J360
NOTES:
- Duration of individual DTM component activation is limited to 30 seconds but can be stopped at any time by pressing the -> button
- Switch OFF the ignition before repeating the Output Diagnostic Test Mode checks
Work Sequence:
- Start engine and let idle
- Connect VAG 1551/1552 Scan Tool
- Press 0 and 1 buttons to select address word 01 "engine electronics"
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Operate Scan Tool taking display information into account
- Press 0 and 3 buttons to select Function 03 "Output Diagnostic Test Mode"
Display will appear as shown:
Rapid data transfer Q
03 Output Diagnostic Test Mode
- Press Q button to enter input
Display will appear as shown:
Output Diagnostic Test Mode
Cold Start Valve - N108
NOTE: Activating the Cold Start valve can influence combustion noise considerably (pre-ignition).
If no change in combustion noise is heard:
- Check injection adjuster control range. Testing and Inspection
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
EGR Vacuum Regulator solenoid valve - N18
valve must click
NOTE: Because of engine noise levels, valve clicking cannot be heard and must therefore be touched to verify operation.
If valve does not click:
- Check Exhaust Gas Recirculation and Mass Air Flow sensor function. Testing and Inspection
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
A/C compressor interruption
NOTES:
- A/C compressor shut-off is checked
- The test step is also recalled on vehicles without A/C.
- The A/C compressor must stop within 5 secs. (visual check) then start approx. every 5 secs. and then stop.
If compressor is NOT switched OFF
- Check A/C compressor cut-off, see wiring diagrams
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Fuel cut-off valve - N109
engine must stop running
If NOT:
- Switch OFF ignition
- Unscrew fuel cut-off valve N109 and remove any metal particles or dirt. Locations , item 2
- Repeat Output Diagnostic Test Mode
If engine will not stop running:
- Replace fuel cut-off valve N109
- Continue Output Diagnostic Test Mode with engine stopped and ignition switched ON
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Wastegate Bypass Regulator valve - N75
valve must click
NOTE: Valve clicking is difficult to hear and is therefore best checked by touching.
If valve does not click:
- Check Wastegate Bypass Regulator valve N75. Testing and Inspection
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Glow plug relay - J52
relay must click
NOTES:
- The production number on the reverse side of the relay must be "180"
- Relay ON/OFF switching can also be observed by watching the interior light as it becomes brighter and darker due to the high glow plug power consumption
If relay does not click:
- Check glow plug relay, see wiring diagrams
- Press -> button
Display will appear as shown:
Output Diagnostic Mode Test ->
Glow plug indicator light - K29
Glow plug indicator light must blink
If the Glow plug indicator light does not blink:
- Connect VAG 1598/18 Test Box to ECM harness connector. Pinout Values and Diagnostic Parameters
- Connect socket 48 (indicator light wiring) with socket 46 (Ground)
- Switch ON ignition
If warning lamp lights up now, but not during Output Diagnostic Test Mode:
- Replace Engine Control Module
If Glow plug indicator light does not light up:
- Check wiring
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Low heater output relay - J359
relay must click
If relay does NOT click:
- Check coolant pre-heating low heater output relay, see wiring diagrams
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
High heater output relay - J360
relay must click
If relay does not click:
- Check coolant pre-heating high heater output relay, see wiring diagrams
- Press -> button
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Press 0 and 6 buttons to select Function 06 "End data transfer"
- Switch OFF ignition