Volkswagen Workshop Service and Repair Manuals > Golf Mk4 > Engine | 4-cylinder injection engine | Mixture preparation system, electronic inj.,Gas | Engine control unit | Adapting functions and components | Reading and erasing engine control unit fault memory

Reading and erasing engine control unit fault memory

If fault memory is erased, engine control system loses teach-in values. This may cause handling problems depending on vehicle's mileage.

If this is the case:

–	Carry out long road test until handling problems are remedied.

Special tools and workshop equipment required

t	Vehicle diagnosis, testing and information system -VAS 5051A- or Vehicle diagnosis, testing and information system -VAS 5051B-

t	Diagnosis lead -VAS 5051/1- or diagnosis lead -VAS 5051/3-

Procedure

–	Connect vehicle diagnosis, testing and information system -VAS 5051B- as follows:

–	Remove cover -1--in direction of arrow-.

–	Plug connector of diagnosis lead -VAS 5051/1- or diagnosis lead -VAS 5051/3- into diagnosis connector.

–	Start engine and run at idling speed.

Only if engine does not start

–	Switch on ignition.

Select operating mode:

–	Press button on display for “Vehicle self-diagnosis”.

Select vehicle system:

–	Press “01 - Engine electronics” button on display.

Control unit identification and engine control unit code appear on display.

Note

A print-out can be made if needed. Press the Print key.

Select diagnostic function:

–	Press “02 - Interrogate fault memory” button on display.

–	If no fault is stored in engine control unit “0 fault detected” is displayed.

–	If faults are stored in the engine control unit, these are shown one below the other on the display.

–	Press ← button.

–	Press “05 - Erase fault memory” button on display.

–	Press function “06-End output”.

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