Diagnostic Trouble Codes (DTC)

The Motronic Engine Control Module (ECM) can identify malfunctions and store them in memory in the form of a Diagnostic Trouble Code (DTC).

• The Motronic ECM (after evaluating the information), differentiates between 34 possible malfunctions and stores them until DTC memory is erased. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION  .
• The Motronic ECM is equipped with diagnostic capability for 8 possible Output Diagnostic Test Mode (DTM) checks (formerly called Output Checks). See DIAGNOSTIC TEST MODES (DTM)  .
• Output DTM checks can ONLY be initiated with the engine NOT running. DTC memory, on the other hand, should ONLY be checked with the engine running, (if possible).
• Full access to the vehicle OBD system requires the (VAG 1551) scan tool. The (VAG 1551) Scan Tool (ST) has built in printout capability.
• If a malfunction exists for a sufficient time, it is permanently stored (until intentionally erased) as static.
• If a malfunction appears momentarily or for insufficient time to be classified as static it will be stored as sporadic, a process that repeats itself continuously.
• If the sporadic malfunction does not reoccur during the next 50 engine starts, it will automatically be erased from DTC memory.
• If several malfunctions occur at the same time, check ground connections at the rear of the engine, and between the left side of the engine cylinder block and left long member for corrosion or damage, repair or replace as necessary. See GROUND CHECK  under ECM GROUND & VOLTAGE CHECK.