Characteristics of On Board Diagnostic (OBD)

Characteristics Of On Board Diagnostic (OBD)

The Engine Control Module (ECM) and, in vehicles with Multitronic or automatic transmission 01 V, the Transmission Control Module (TCM) are equipped with DTC memory.

Malfunction recognition
If malfunctions occur at the emission relevant systems or components, they are stored in DTC memory with a description of the malfunction type.

The stored malfunctions can be checked with a standard diagnostic tester. Diagnostic Mode 03 - Read DTC Memory

The Engine Control Module (ECM) and Transmission Control Module (TCM) differentiate between different DTCs after evaluating the information.

If the ECM or TCM recognizes malfunctions that lead to a worsening of emissions values, it indicates them by lighting the Malfunction Indicator Lamp (MIL) -K83- in the instrument cluster. Malfunction Lamp For on Board Diagnostic (OBD)/Malfunction Indicator Lamp (MIL) -K83- In Instrument Cluster

E-Gas -relevant malfunctions are also indicated by the Electronic Power Control (EPC) Warning Lamp -K132- ("EPC warning lamp") in the instrument cluster.

When disconnecting harness connectors from Engine Control Module (ECM) or Transmission Control Module (TCM), or when disconnecting battery, all adaptation values in the control modules are erased. DTC memory content will remain intact however. After re-connecting harness connectors or battery, or after performing corrective actions, the following work steps must be performed in the mentioned sequence:
1. Check DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If DTC memory was erased, generate readiness code.

- End diagnosis and switch ignition off.