Output Diagnostic Test Mode (DTM) (Function 03)
Output Diagnostic Test Mode, checksSpecial tools, testers and auxiliary items:
- VAG1551 or VAG1552 scan tool
- VAG1551/3 adaptor cable
- VAG1598/18 test box
- VW 1594 connector test kit
- Multimeter (Fluke 83 or equivalent)
- VAG1527B voltage 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
NOTE: Activation of each component in the output DTM sequence is limited to 30 seconds, but the sequence can be advanced at any time by pressing the -> button
Switch the ignition off before repeating the Output Diagnostic Test Mode checks
Work Sequence:
- Start engine and let idle
- Connect VAG1551 or VAG1552 scan tool
- Press -0- and -1- buttons to select "Engine Electronics" address word 01
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Operate scan tool accoring to directions on display
- Press -0- and -3- buttons to select "Output Diagnostic Test Mode" function 03
Display will appear as shown:
Rapid data transfer Q
03 Output Diagnostic Test Mode
- Press -Q- button to confirm input
Display will appear as shown:
Output Diagnostic Test Mode
Cold start injector - N108
NOTE: Activating the cold start injector can influence combustion noise considerably (pre-ignition).
If there is no change in combustion noise:
- Check injection adjuster control range. Quantity Adjuster Control Range
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
EGR vacuum reg. solenoid valve - N18
EGR vacuum regulator solenoid 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. EGR and Mass Air Flow Sensor Function Testing
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
A/C compressor interruption
NOTE: 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, refer to Heating and Air Conditioning, Testing and Inspection, Procedures Testing and Inspection
- 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
- Repeat Output Diagnostic Test Mode (DTM)
If engine will not stop running:
- Replace fuel cut-off valve N109
- Continue Output DTM with engine stopped and ignition switched ON
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Wastegate Bypass Regulator valve - N75
Wastegate bypass regulator 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. Boost Pressure Control, Checking
- Press -> button
Display will appear as shown:
Output Diagnostic Test Mode ->
Glow plug relay - J52
Glow plug relay must click
NOTE: The production number "180" on the reverse side of the relay.
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, refer to Glow Plug System, Testing and Inspection, Procedures, Glow Plug System Troubleshooting Testing and Inspection
- 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 Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM)
If Glow plug indicator light does not light up:
- Check wiring, refer to Glow Plug System, Testing and Inspection, Procedures, Glow Plug System Troubleshooting Testing and Inspection
- 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, refer to Diagrams, Electrical Electrical 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, refer to Diagrams, Electrical Electrical Diagrams
- Press -> button
Display will appear as shown:
Rapid data transfer HELP
Select function XX
- Press -0- and -6- buttons to select "End Output" function 06
- Press -Q- to confirm input
- Switch ignition off