Audi TT (2007 year). Manual - part 58

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not 
 permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability 
     with respect to the correctness of information in this document. Copyright by AUDI AG.

2.2

Removing and installing exhaust gas

temperature sender 1 -G235-

Removing
– Unplug electrical connector -1- (black) for exhaust gas tem‐

perature sender 1 -G235- and move wiring clear.

Note

Disregard -items 2, 3 and 4-.

Note

The connection can be accessed from below.

– Unscrew exhaust gas temperature sender 1 -G235- -item 1-

from exhaust manifold.

Note

Disregard -arrows-.

Installing
• Tightening torque 

⇒ page 222

 .

Installation is carried out in the reverse order; note the following:

Note

♦

Coat threads of exhaust gas temperature sender with high-

temperature paste; for high-temperature paste refer to ⇒ 

Electronic parts catalogue .

♦

Fit all cable ties in the original positions when installing.

Installation position of exhaust gas temperature sender -G235- :

• The angled part of the pipe must have a clearance of -a- = 3

… 5 mm from the bolt on the turbocharger support.

2. Exhaust gas temperature control    

223

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not 
 permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability 
     with respect to the correctness of information in this document. Copyright by AUDI AG.

2.3

Removing and installing exhaust gas

temperature sender 3 -G495-

perature sender 3 -G495- and move wiring clear.

Note

Disregard -items 1, 2, 4-.

– Remove exhaust gas temperature sender 3 -G495- -item 1-.

Note

Disregard -items 2, 3-.

Installing
• Tightening torque 

⇒ page 222

 .

Installation is carried out in the reverse order; note the following:

Note

♦

Coat threads of temperature sender with high-temperature

paste ⇒  Electronic parts catalogue .

♦

Fit all cable ties in the original positions when installing.

Installation position of temperature sender before particulate filter

-G495- :
• Angled section of pipe faces towards left side of vehicle.
• Angle -α- = approx. 7° to left.

Note

Disregard -arrow-.

224

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not 
 permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability 
     with respect to the correctness of information in this document. Copyright by AUDI AG.

2.4

Removing and installing exhaust gas

temperature sender 4 -G648-

Removing
– Unplug electrical connector -2- (orange) for exhaust gas tem‐

perature sender 4 -G648- and move wiring clear.

Note

Disregard -items 1, 3 and 4-.

– Unscrew exhaust gas temperature sender 4 -G648- -item 1-

from exhaust pipe behind particulate filter.

Note

Disregard -item 2-.

Installing
• Tightening torque 

⇒ page 222

 .

Installation is carried out in the reverse order; note the following:

Note

Coat threads of temperature sender with high-temperature paste

⇒  Electronic parts catalogue .

2. Exhaust gas temperature control    

225

Protected by copyright. Copying for private or commercial purposes, in part or in whole, is not 
 permitted unless authorised by AUDI AG. AUDI AG does not guarantee or accept any liability 
     with respect to the correctness of information in this document. Copyright by AUDI AG.

3

Exhaust gas recirculation system

Exhaust gas recirculation system
♦ To improve exhaust emission values, exhaust gas is recircu‐

lated to the combustion chambers, thus reducing the combus‐

tion chamber temperature.

♦ The exhaust gas recirculation system is activated by the en‐

gine control unit -J623- via the exhaust gas recirculation valve

-N18- and the exhaust gas recirculation potentiometer -

G212- .

♦ The exhaust gas recirculation is switched off after approx. 2

minutes at idling speed.

♦ Restart engine or briefly increase engine speed above 1500

rpm when longer checks are necessary. Then repeat meas‐

urement.

Cooling system for exhaust gas recirculation system
♦ To further improve the exhaust emission values, the exhaust

gas recirculation system is equipped with a cooler that is con‐

nected into the engine cooling system.

♦ Under certain operating conditions, the flow of exhaust gas

that is recirculated to the combustion chamber is routed via

this cooler. The exhaust gas temperature is thereby reduced,

further lowering the combustion temperature and improving

the exhaust emission values.

♦ The engine control unit -J623- determines when the recircu‐

lated exhaust gas is routed via the cooler. The control unit

actuates a vacuum unit via the exhaust gas recirculation cool‐

er change-over valve -N345- , and the vacuum unit in turn

operates the change-over flap for the exhaust gas recircula‐

tion cooler.

3.1

Diagram of vacuum connections

⇒ “1.1 Diagram of vacuum connections”, page 197

 .

226