Self-diagnosis of the injection system (VW Polo 3)

The fuel injection system control unit is equipped with a fault memory, which records faults in sensors or systems, indicating the type of fault. Sometimes faults occur that are random in nature (sporadic). Such faults are additionally designated by the symbol "S/P". If a sporadic fault has not occurred after 50 engine starts, it is automatically erased (deleted) from the memory. If faults affecting the vehicle control systems are detected, the warning light comes on. Faults can be read using the VAG 1551 fault code reader or the VAG 1552 tester. After the fault has been eliminated, it must be deleted from the fault memory.

Fault memory is divided into permanent and temporary (the fault is cleared after 50 engine starts).

The selection of functions using the VAG 1551 fault code reader or the VAG 1552 tester are shown in Table 3.3.

Table 3.3. Selecting functions using the reader