sensor AUDI A4 1997 B5 / 1.G APB Engine Exhaust System Components Workshop Manual

26-6

Right-hand catalytic converter:

Left-hand catalytic converter: - Disconnect connector -1- for oxygen sensor at bulkhead.

- Disconnect connector -2- for oxygen sensor at bulkhead.
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26-19

Exhaust gas temperature sensor,
checking for function


Special tools and equipment

Test requirement:
WARNING!
VAS 5051 with VAG 5051/1
orVAG 1551 with VAG 1551/3ACoolant Temperature at least 80 C. During a road test in an airbag-equipped vehicle, test equipment
must always be fastened to and operated from the rear seat by a
second technician. When driving or riding in an airbag-equipped vehicle, NEVER hold
the scan tool or other test equipment in your hands or lap while in
motion. Objects between you and the airbag increase the risk of
injury in an accident.
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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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26-23

- Repeat test for bank 2 measuring value block
221 If specified values are not obtained and there is a
malfunction stored in the Diagnostic Trouble
Code (DTC) memory:

- Check exhaust gas temperature sensor, Page
26
-24
.
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26-24


Exhaust gas temperature sensor,
checking

Special tools and equipment

VAG 1526A
VAG 1527B
VAG 1594A
VAG 1598/31
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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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