Engine Control Module (ECM) Activation, Testing

Engine Control Module (ECM) Activation, Testing

Special tools, testers and auxiliary items required

• Test Box 105 Pin (V.A.G 1598/42-1) and Test Adapter (V.A.G 1598/47)

• Vehicle Diagnostic, Testing and Information System (VAS 5051 A) with Multimeter Leads (VAS 5051/7)

• These functions depend on the version of the engine and engine control module and may not be available on all vehicles. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding" (for the respective engine control module).

• On vehicles with a manual climate control system, the A/C control module (J301) exchanges the information via the databus system with each engine control module. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding".

• The Heater control module (J65) has a potentiometer installed. This potentiometer is operated via rotary switch for temperature preselect - A - and therefore transmits position of rotary temperature preset switch to engine control module.






- On vehicles with diagram-mapped cooling, activation of Map Controlled Engine Cooling Thermostat (F265) is influenced by the respective Engine Control Module (ECM) on certain engines. If rotary switch for temperature preselect - A - is located at "Warm" stop or closely in front of it, coolant temperature is reduced (limited to approximately 95 °C) to prevent excessive air blower temperatures from heater air vents. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding" for respective ECM.






- In vehicles with gasoline direct fuel injection engine FSI, mixture formation is influenced by respective Engine Control Module (ECM) on certain engines. If rotary switch for temperature preselect - A - in area of "Warm" stop or closely in front of it, improved coolant heating (and thus better heating performance) is attained by departing the stratified charge range for engine mixture formation and the engine runs normally. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding" (for respective ECM).

- In vehicles for which this function is designated, a voltage of approximately 5 volts is supplied (by respective ECM) at connector - B - between terminal 1 and 10 with ignition switched on. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding" (for respective ECM).






- A voltage between approximately 0.5 volt ("cold") and approximately 4.5 volt ("warm") is sent via terminal 2 inside the connector - B - to the heater control module (J65) - A - depending on the position of the temperature preset rotary switch - A -. Each engine control module knows the position of the temperature preset rotary switch - A - by this voltage. The engine control module evaluates this voltage and then controls the coolant temperature and the mixture formation. Check using Vehicle diagnosis, testing and information system (VAS5051B) under "Guided Fault Finding" (for each engine control module).