SEAT Workshop Service and Repair Manuals > Leon Mk2 > Engine, mixture preparation | Motronic injection and ignition system (4-Cyl.) | Self diagnosis, V.A.G Inspection Service | General to self-diagnosis

Connecting fault reader V.A.G 1551 and selecting engine electronics control unit > < Features of self-diagnosis

Motronic injection and ignition system (4-Cyl.)

General to self-diagnosis

Technical data of self-diagnosis

Control unit identification

The control unit version is displayed when the fault reader V.A.G 1551 or the vehicle system tester V.A.G 1552 is connected and engine electronics control unit selected .

Technical data


Engine code			AJH
System designation			Motronic M3.8.5
Exhaust emission conforms to			D3 standard
Self-diagnosis			yes
Final control diagnosis			yes
Method of data transfer to V.A.G 1551/1552			Rapid data transfer
Control unit coding			V.A.G 1551/1552
Fault memory			Non-volatile memory1)
Memory for "Learnt values"			Volatile memory2)
Lambda control			yes
Knock control			2 knock sensors
Intake manifold change-over			no
Camshaft adjustment			no
Charge air control			yes

1) Independent of voltage supply.

2) Values are erased when voltage supply is interrupted.

Selectable functions when using the fault reader V.A.G 1551 or V.A.G 1552

The prerequisites for selecting the desired functions can be taken from the following table.


Function		Prerequisite
Functions on fault reader V.A.G 1551 or on system tester V.A.G 1552		Engine stationary, ignition switched on	Engine running at idling speed	Vehicle being driven
01	Interrogate control unit version	yes	yes	yes
02	Interrogate fault memory	yes1)	yes	yes
03	Final control diagnosis	yes	no	no
04	Basic setting	yes2)	yes3)	no
05	Erase fault memory	yes	yes	yes
06	End output	yes	yes	yes
07	Code control unit	yes	no	no
08	Read measured value block	yes	yes	yes
10	Adapting	yes	no	no
11	Login procedure	no	yes	no

1) Only carry out with ignition switched on, when engine does not start (operate starter for at least 6 seconds first).

2) Must be carried out after the following: Replacing engine control unit, throttle valve control part, engine or disconnecting battery => Page 24-111, Matching engine control unit to throttle valve control part.

3) Lambda regulation learning sequence is introduced at idling speed => Page 24-81, idling check.

Engine, mixture preparation
Motronic injection and ignition system (4-Cyl.) / Self diagnosis, V.A.G Inspection Service / General to self-diagnosis
Technical data of self-diagnosis

Connecting fault reader V.A.G 1551 and selecting engine electronics control unit > < Features of self-diagnosis

SEAT Workshop Service and Repair Manuals

Leon Mk2

Engine, mixture preparation Motronic injection and ignition system (4-Cyl.) / Self diagnosis, V.A.G Inspection Service / General to self-diagnosis Technical data of self-diagnosis

Engine, mixture preparation Motronic injection and ignition system (4-Cyl.) / Self diagnosis, V.A.G Inspection Service / General to self-diagnosis Technical data of self-diagnosis

Engine, mixture preparation
Motronic injection and ignition system (4-Cyl.) / Self diagnosis, V.A.G Inspection Service / General to self-diagnosis
Technical data of self-diagnosis

Engine, mixture preparation
Motronic injection and ignition system (4-Cyl.) / Self diagnosis, V.A.G Inspection Service / General to self-diagnosis
Technical data of self-diagnosis