engine AUDI A4 1996 B5 / 1.G APB Engine Exhaust System Components Workshop Manual

26-5

Catalytic converter, removing and
installing


Removing

- Remove bolts -arrows- and take off engine cover panels -A ... C-.

- Remove air distributor component -arrows-.
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26-16

Exhaust system, checking for leaks


- Start engine and run at idling speed.

- Plug tailpipe (e. g. with rag or stopper) and leave
plugged until check is complete.

- Listen for noise at connection points (cylinder
head/manifold, manifold/turbocharger,
turbocharger/catalytic converter, etc.) to locate
leaks.

- Correct any leaks that are found.
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26-17

Exhaust manifold, removing and
installing


Removing

- Remove engine Page 10
-1 .

- Remove turbocharger Page 21
-1

- Unbolt exhaust manifold.

Installing

Notes:

Replace self-locking nuts.
Replace gaskets.

- Install in reverse sequence.
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26-20

Test sequence

- Connect VAS 5051 tester or VAG 1551 scan
tool and select control module for engine
electronics using "address word" 01. Engine
must run at idle for this.

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel
Injection & Ignition, Engine Code(s): APB, Repair Group 01

Rapid data transfer
HELP
Select Function XX

When indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block" and
press -Q- button to confirm input.
Read measurin
g value block
Q
Input display group number XXX

When indicated on display
- Press buttons -1-, -1- and -2- to select "display group number 112" and
press -Q- button to confirm input.
Read measuring value block 112
1
2
3
4

Indicated on display (1...4 display fields) - Check exhaust gas temperature.
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26-21

- Road test vehicle.


Wide Open Throttle (WOT) at engine
speeds between 5000...6500 RPM must be
reached.

Note:
Exhaust gas temperature must rise to above 980
C so that regulation sets in. Values below 945
C are displayed as 945 C.

Display fields

1 2 3 4
Display group 112: Exhaust temperature
Display
C
%
C
%
Indicated Exhaust temperature,
Bank 1 Enrichment factor,
Sensor, Bank 1 Exhaust temperature,
Bank 2 Enrichment factor,
Sensor, Bank 2
Specified
value 980
1)
90 5
2)
980
90 5
Note: Regulation does not begin
until temperatures above
980 C
If the enrichment factor is
above 30%, there is a
malfunction Regulation does not begin
until temperatures above
945 C
If the enrichment factor is
above 30%, there is a
malfunction
1) During oscillation stage, values around 1025 C may be displayed briefly. 2) During oscillation stage, values of 25 % may be displayed briefly.
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26-22
If values above 20 % are displayed constantly,
then

fuel pressure may be too low,
mass air flow sensor signal may be too small.

- Select measuring value block 220.
Read measuring value block 220
1
2
3
4

Indicated on display (1...4 display fields) - Check exhaust temperature regulation.

Display fields

1 2 3 4
Display group 220: Exhaust gas temperature regulation
Display 1 RPM % % Text
Indicated Engine speed (RPM) Load Duty cycle, Sensor,
Bank 1 Operating condition,
Bank 1
Specified
value > 5000 > 100
42 10
Regulation on
Note: Increase engine speed and load enough that regulation
jumps to "on"
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26-25

Checking voltage supply

- Switch ignition off.

- Remove engine cover (arrows).
- Disconnect connector at exhaust gas temperature sensor.

- Connect VAG 1527B voltage tester as follows:Harness connector terminal
Measure to
3 Engine Ground (GND)
- Operate starter briefly.

LED must light.
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26-26
If LED does not light:

- Perform following tests marked with dots:

Electrical Wiring Diagrams, Troubleshooting & Component Locations
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition,
Engine Code(s): APB, Repair Group 24

Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition,
Engine Code(s): APB, Repair Group 24

Check fuse -S234- (in fuse holder, position 34). Check wire connection from exhaust gas temperature sensor via fuse
-S234- (in fuse holder, socket 34) to Fuel Pump (FP) relay for open
circuit: Check Fuel Pump (FP) relay.
- Connect VAG 1598/31 test box at wiring harness to ECM. Do not
connect ECM.
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26-27


If wire connection is OK:
If the same malfunction occurs again after replacing the exhaust gas
temperature sensor:
Repair Manual, 2.7 Liter V6 5V BiTurbo Fuel Injection & Ignition, Engine Code(s): APB, Repair Group 24
- Check following wire connections for open circuit and short circuit to
Ground (GND) and B+:
Harness connector terminal
VAG 1598/31 test box
Bushing
1 (Bank 1) 61
1 (Bank 2) 20
2 50
- Replace exhaust gas temperature sensor.
- Replace Engine Control Module (ECM).
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26-28

Exhaust gas temperature sensor,
removing and installing


- Remove bolts (arrows) and remove engine covers -A- and -B-.

- Remove air distributor (arrows).
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