Engine Control Module, Removing and Installing Audi TT 8N

The protective housing has to be removed before the 60-pin connector can be disconnected from the control module (e.g. to connect the test box or replace the engine control module).

Special tools and equipment required

Scheme 49

1. Puller T10130

Removing

Note. When replacing the engine control module, select the diagnosis object "Replace engine control module" in "Guided Fault Finding". For this purpose, use the vehicle diagnostic, testing and information system VAS 5051 A.

1. Switch off ignition and remove ignition key.

Scheme 50

1. Use screwdriver to pry off covers at wiper arms (arrows) and unscrew hex nuts.

Scheme 51

1. Use puller T10130 to remove wiper arms -1- from wiper shafts.

Scheme 52

1. Pull off rubber seal -1- on plenum chamber cover.
2. Remove plenum chamber cover -2- and lay aside (toward windshield).
3. Disconnect electrical connectors for windshield washer heating.

Scheme 53

1. Unclip cover -2-.
2. Disconnect multiple connectors -1- and -3- at engine control module.
3. Release retaining tab (arrow) and pull engine control module forward out of bracket.

Installing

Installation is performed in the reverse order of removal. After the installation of a new engine control module, perform the following operations

1. Activate engine control module in "Guided Fault Finding" under diagnosis option "Replace engine control module".

Note. For this purpose, use the vehicle diagnostic, testing and information system VAS 5051 A.

Scheme 54

Note. The fuel pressure regulator regulates the fuel pressure according to the intake manifold pressure. The pressure drop at the injectors remains constant for each engine speed and load range.

Special tools and equipment required

1. Pressure gauge V.A.G 1318
2. Adapter set V.A.G 1318/17
3. Hose clamp pliers V.A.G 1921

Requirements

1. Fuel pump relay OK
2. Fuel pump OK; checking

Refer to 20 - FUEL SUPPLY

1. Fuel filter OK
2. Battery voltage at least 12.7 V

Checking system pressure

1. Briefly open fuel tank filler cap (to release pressure).

Scheme 55

1. Open cover of use carrier and remove fuse 28 for Fuel pump -G6- (pre-supply pump).

Scheme 56

1. Disconnect fuel supply line -1- by pressing release tab.

Scheme 57

1. Connect pressure gauge V.A.G 1318 with adapters V.A.G 1318/9 and V.A.G 1318/17 to fuel supply line.
2. Open cut-off valve on pressure gauge. Lever must point in direction of flow.
3. Reinstall fuse 28 for Transfer Fuel Pump (FP) -G6- (pre-supply pump) in fuse carrier.
4. Start engine and run at idling speed.

1. Measure fuel pressure

Specification: approx. 3.5 bar

Scheme 58

1. Disconnect vacuum hose at fuel pressure regulator.

Fuel pressure must increase to approx. 4.0 bar

1. Switch off ignition.
2. Check for leaks and residual pressure by watching drop in pressure on pressure gauge.

After 10 minutes pressure must still be at least 3.0 bar

If the residual pressure drops below 3.0 bar

1. Start engine and run at idling speed.

Scheme 59

1. Allow pressure to build up, then switch off ignition. Simultaneously, close cut-off valve of pressure gauge V.A.G 1318 (lever perpendicular to direction of flow - arrow-)
2. Observe pressure drop on pressure gauge.

If the pressure now does not drop

1. Check fuel pump non-return valve.

If the pressure drops again

1. Open cut-off valve on pressure gauge (lever points in direction of flow).
2. Start engine and run at idling speed.
3. Allow pressure to build up, then switch off ignition. Simultaneously, tightly clamp off return hose (with blue marking).

If the pressure now does not drop

1. Replace fuel pressure regulator.

If the pressure drops again

1. Check line connections, O-rings on fuel rail and injectors for leaks.
2. Check pressure gauge for leaks.

Note. Before removing the pressure gauge, release the fuel pressure by opening the cut-off valve. Hold a container under the connection.

Scheme 60

1 - Fuel return hose

2 - Fuel supply hose

3 - Fuel rail

4 - Hex socket head bolt, 10 Nm

5 - Fuel pressure regulator

6 - O-ring

7 - O-ring

8 - Retaining clip

1. Check for correct fit on fuel rail

9 - O-ring

1. Removing and installing. Refer to «Fuel injectors, removing and installing»(ref-276275-S25120213012008010300000)
2. Replace
3. Lubricate with clean engine oil

10 - Retaining clip

1. Check for correct fit on fuel rail

11 - O-ring

1. Removing and installing. Refer to «Fuel injectors, removing and installing»(ref-276275-S25120213012008010300000)
2. Replace
3. Lubricate with clean engine oil

12 - Fuel injector