DTC Memory Checking and Erasing

DTC memory, checking (function 02) and erasing (function 05)

When the DTC memory is erased, some values are learned by the engine control module. All values learned by the engine control module will be erased when the engine control module connector is pulled off or the battery is disconnected. However the contents of the DTC memory are retained. When the engine is subsequently started the idling could be rough for a brief period. In this case leave the engine running for a few minutes at idle speed or perform a longer test drive, until the learning process is completed. Procedure after correcting voltage supply open circuit. Procedure After Correcting Voltage Supply Open Circuit

Special tools, test equipment and auxiliary items
- VAG 1551 scan tool (or vehicle system tester VAG 1552) with cable VAG 1551/3B

Work sequence


NOTE:
All functions which could previously be performed with VAG 1551/1552 can also be performed with the tester VAS 5051.


- Connect scan tools VAG 1551 or 1552 and select engine control module with "Address word" 01. Engine must be running at idle speed. Connecting scan tool and selecting engine control module. [1][2][3]Connecting VAG 1551 Scan Tool

Only when engine does not start:
- Operate starter for approx. 6 seconds and then do not switch off ignition.

- Switch on scan tool printer with PRINT button. (Lamp in button must light up.)

Indicated on display


Rapid data transfer HELP
Select function XX


- Operate scan tool taking into account information on display.
- Press buttons -0- and -2- for function "Check DTC memory" and confirm entry with -Q- button.

The number of DTCs stored or "No DTC recognized!" will be shown on the display.


X DTC recognized!


If no DTC is stored:
- Press -> button.

If one or more DTCs are stored:
Stored DTCs are displayed and printed out one after the other.

After the stored DTCs have been printed out, the display will show:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -5- for function "Erase DTC memory" and confirm entry with -Q- button.

Indicated on display


Rapid data transfer ->
DTC memory is erased!


NOTE: If the ignition is switched off between "Check DTC memory" and "Erase DTC memory" the DTC memory will not be erased. Some malfunctions (e.g. for EPC) are erased after starting on and off the ignition several times.


- If DTC memory was erased readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes

- Press -> button.

Indicated on display


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -6- for function "End output" and confirm entry with -Q- button.
- Using Diagnostic Trouble Code (DTC) table, repair malfunctions which appear on print-out:

- SAE P0 codes. SAE P0 Codes
- SAE P1 codes. SAE P1 Codes

- Road test vehicle.

Observe the valid safety precautions during a test drive. Read Measuring Value Blocks (Function 08)

During the road test the following operating conditions must be fulfilled:

- The coolant temperature must exceed 85 °C

When the temperature is reached, the operating conditions must be attained several times:

- Idling
- Part throttle
- Enrichment
- Wide open throttle
- Overrun

- At wide open throttle the engine speed must exceed 3500 RPM

- Again check DTC memory of all control modules using "automatic test sequence."
- Generate readiness code again. Monitors, Trips, Drive Cycles and Readiness Codes
- If DTC memory has been erased or engine control module was disconnected from permanent positive, readiness code must be generated again. Monitors, Trips, Drive Cycles and Readiness Codes