About Trouble Codes

DTC Table

Notes on DTC table
- When commencing fault finding of the vehicle control modules, always start with function "Automatic test sequence" by pressing keys 0 and 0 because the control modules are interconnected with a data-BUS wire. This checks the fault memories of the control modules in the vehicle.
- If fault occur only occasionally or if the DTC memory was not erased after rectifying the faults, these faults will be displayed as "sporadic DTCs" for a stipulated period of time.
- All the possible faults which can be recognized by the ABS control module (J104) and printed-out on VAG 1551, are listed on the following pages according to the 5 digit fault code.
- Fault code appears (in the "Rapid data transfer" mode) only on the print-out.

Example:

Fault code P code Fault type code
5 digit 5 digit 3 digit
18258 P1850 035

- The 5 digit P code which may appear next to the fault code, is for use with the On Board Diagnostic II and may be disregarded.
- The 3 digit fault type code is a data code and may be disregarded, but the fault type text is of use.
- If components are indicated as being faulty during DTC memory interrogation, additionally test wiring to the components for short and open circuits according to wiring diagram.
- On completion of repairs always check the DTC memory with scan tool VAG 1551 or the new tester VAS 5051 and erase.

VAG 1551 scan tool display

No DTC recognized!

If "No DTC recognized" appears after performing repairs, the On Board Diagnostic (OBD) is completed.

In the event that the automatic transmission does not operate properly despite On Board Diagnostic (OBD) perform Output Diagnostic Test Mode and measured value block (display group number 007). Output Diagnostic Test Mode (DTM) (Function 03) Reading

Further information concerning function, can be found in Self-study program No. 180.