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Home >> Audi >> 2012 >> Q5 2.0T >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Access/Start Authorization System Description >> 01 On Board Diagnostic >> Terminal Control And Engine Starting
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Terminal Control And Engine Starting

General Information 

The access/start authorization system authorizes terminal 15 and the engine to start. There can be differences between "starting the engine using a key" and "starting the engine with the advanced key".

Requirement for Terminal 15 ON 

In addition to correct wiring, the following requirements must be met in order to switch on terminal 15:

Requirement for Starting Engine 

In addition to the requirements for Terminal 15 ON, the following requirements must be met in order to start the engine:

Starting with Key 

Immobilizer V has a completely new operating logic for controlling the terminal and for starting the engine. The electronic ignition lock differentiates between only two different key positions when the key is inserted (S contact):

The following operating concept results:

Condition Prior to the Action Action Condition After the Action
S contact OFF (ignition off, engine off) -- Insert the key S contact ON (ignition off, engine off)
S contact ON (ignition off, engine off) -- Remove the key (automatic transmission selector lever in P) S contact OFF (ignition off, engine off)
S contact ON (ignition off, engine off) -- Push the key (manual transmission clutch pedal not depressed; with automatic transmission, brake pedal not depressed) Ignition ON (engine OFF)
S contact ON (ignition off, engine off) -- Push the key (manual transmission clutch pedal depressed; with automatic transmission, brake pedal depressed and selector lever in N or P) Engine ON
Ignition ON (engine OFF) -- Push the key (manual transmission clutch pedal not depressed; with automatic transmission, brake pedal not depressed) S contact ON (ignition off, engine off)
Ignition ON (engine OFF) -- Push the key (manual transmission clutch pedal depressed; with automatic transmission, brake pedal depressed and selector lever in N or P) Engine ON
Engine ON -- Push the key (manual transmission vehicle is standing; automatic transmission selector lever in N or P) S contact ON (ignition off, engine off)

It switches over to the emergency shut off of the engine. This applies to both manual transmission and automatic transmission vehicles. The following will trigger an emergency shut off:

-- Holding the key pushed in for too long

-- Pushing the key two within a second

Starting with Advanced Key 

The new operating logic for the terminal control and for starting the engine on vehicles with "advanced key" is the same as it was previously explained for starting a vehicle by the key. The electronic ignition lock differentiates between two different conditions conditions:

The following operating concept results:

Condition Prior to the Action Action Condition After the Action
S contact OFF (ignition off, engine off) -- Access/start authorization button pressed (on a manual transmission: clutch pedal not depressed; with automatic transmission, brake pedal not depressed) Ignition ON (engine OFF)
S contact OFF (ignition off, engine off) -- Access/start authorization button pressed (manual transmission clutch pedal depressed; with automatic transmission, brake pedal depressed and selector lever in N or P) Engine ON
Ignition ON (engine OFF) -- Access/start authorization button pressed (manual transmission clutch pedal depressed; with automatic transmission, brake pedal depressed and selector lever in N or P) Engine ON
Ignition ON (engine OFF) -- Access/start authorization button pressed (manual transmission clutch pedal not depressed; with automatic transmission, brake pedal not depressed) S contact ON (ignition off, engine off)
Ignition ON (engine OFF) -- Access/start authorization button pressed (manual transmission clutch pedal not depressed; with automatic transmission, brake pedal not depressed) and driver door open S contact OFF (ignition off, engine off)
Engine ON -- Access/start authorization button pressed (manual transmission vehicle standing; automatic transmission selector lever in N or P) and driver door closed. S contact ON (ignition off, engine off)
Engine ON -- Access/start authorization button pressed (manual transmission vehicle standing; automatic transmission selector lever in N or P) and driver door open. S contact OFF (ignition off, engine off)
S contact ON (ignition off, engine off) -- Access/start authorization button pressed (manual transmission clutch pedal not depressed; with automatic transmission, brake pedal not depressed)or-- Open the driver door.or-- Lock the vehicle from the outside. S contact OFF (ignition off, engine off)

Also with the advanced key an emergency engine shut off occurs, which is the same with both manual and automatic transmissions. Two requirements must be met via the access/start authorization button -E408- for an emergency shut off:

-- The brake pedal is depressed.

-- Speed <10 kmh

The following will trigger an emergency shut off:

-- The button not held pressed for a long time.

or

-- The button is pressed twice within one second.

Ignition Key Lock 

Electronic ignition lock will mechanically lock when the key is inserted so that the driver cannot pull it out. The key is unlocked again as soon as the ignition is turned off. The unlock takes place when there is current from the solenoid, which released the key. The solenoid is inside the electronic ignition. It receives current directly from the comfort system central control module.

Depending on the type of transmission installed in the vehicle, there is another condition which releases the key:

With an automatic transmission, the selector lever must be in P.

With a manual transmission, the vehicle must be standing.

If, due to a technical fault, there is no current flowing to the solenoid in the ignition key lock while the key is in the ignition lock, the key will remain locked. In order to unlock the vehicle, a mechanical emergency key with a key bit can be used. The emergency key is locked in the ignition lock and can be used to mechanically unlock the central locking via the mechanical lock inside the driver door. The mechanical emergency key can be used to open the vehicle via the mechanical lock inside the driver door, if it is not possible to unlock the vehicle using the remote control. It is also needed to deactivate the front passenger airbag.

Service Information 

It is important that the comfort system central control module is coded correctly under diagnosis address "05 - access/start authorization" because there is a difference between a vehicle with an automatic transmission and one with a manual transmission. Check the coding in "Guided Fault Finding " or "Guided Functions" using the functionality test "05 - coding control module, (Repair Group 96)". Coding can only be performed using "Software Version Management (SVM)".