2000 AUDI A4 catalytic converter

- Additional Heated Oxygen Sensor (HO2S) probe after Three Way Catalytic Converter (TWC)
- New engine control module with five individual connectors, total of 96 terminals
- New On Board Diagnostic (OBD) program with address word 01 and address word 33.
Engine control modules: 8D0 906 266
8D0 906 266 A
These are the successor versions of the 8A0 906 266 D control module with On Board Diagnostic II (OBD II)
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01-4

Malfunction Indicator Lamp (MIL),
functions


Functional testing:
The Malfunction Indicator Lamp (MIL) must light up every time the
ignition is switched on and go out after the engine starts. If a
malfunction is recognized by the engine control module or the
transmission control module, this is indicated by the MIL lighting up. If the MIL lights up continuously, there is a malfunction present that
makes the exhaust gas worse. In this case, the DTC memory for the
engine control module and/or the transmission control module should
be checked. If the MIL starts to blink, there is a malfunction that can lead to
damage of the three way catalytic converter (e.g. combustion misfiring
with high misfiring rate). In this case, driving should only continue with
reduced power (until the MIL goes off or lights up continuously) and
the malfunction should be eliminated as quickly as possible.
- Switch ignition on: the MIL must light up. If the MIL does not light up,
check wiring according to wiring diagram and/or replace lamp.
- Start engine and let idle: MIL must go out after a couple seconds. If the
MIL does not go out after the engine starts, check DTC memory for the
engine and/or transmission control modules (malfunctions in DTC
memory).
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01-26
Diagnostic Trouble Code (DTC) table


Following are all the possible malfunctions that can be recognized by the Engine Control Module (ECM) -J192- and
printed on the VAG 1551 scan tool printer, listed according to code identifier ( SAE and VAG codes).
Malfunctions that switch the MIL on never or immediately are set as "sporadic" each time the engine is started. If the
malfunction occurs again, the "sporadic" status is set again. For malfunctions that only switch the MIL on after two trips
with malfunction, the "sporadic" status is only erased after an OK diagnosis.
If the MIL lights up with engine running, there is a malfunction that makes the exhaust gas worse. If the MIL lights up and
the engine is running, there must in any case be a malfunction stored in the DTC memory of the engine control module
and/or of the transmission control module. In this case, the DTC memory of the engine control module and/or the
transmission control module must be checked.
If the MIL starts to blink, there is a malfunction present that can lead to three way catalytic converter damage (e.g.
combustion misfiring with high misfiring rate). In this case, the trip should be continued with reduced power (until the MIL
goes out or lights up continuously) and the malfunction should be eliminated as quickly as possible.
The malfunction is not stored in the DTC memory immediately and the MIL is not switched on immediately with some
malfunction types, but only after two successive trips with or without preceding cold start (-10 to 30 C (14 to 86 F)
and malfunction occurring (malfunction recognition twice). The MIL switching condition is always specified in the Diagnostic Trouble Code (DTC) table.
Combustion misfiring with high misfiring rate is displayed immediately with the MIL blinking, since the three way catalytic
converters can be damaged. In this case, driving should continue only with reduced power and the malfunction should be
eliminated as soon as possible.
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01-40

Output on GST and/or
on VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0135 / 16519
O2 Sensor Heater Circuit
Malfunction (Bank 1
Sensor 1) Harness connector for Oxygen Sensor
(O2S) heater -Z19- (B1-S1) loose or
corroded due to moisture in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection for Oxygen Sensor
(O2S) heater -Z19- (B1-S1) faulty, or heater
-Z19- faulty

- Check O2S heater -Z19- (B1-S1) page 24
-51


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
For troubleshooting
Display group 040
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:

The heating of the O2S in front of the Three Way Catalytic Converter (TWC) are switched on by the fuel pump relay.
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01-41

Output on GST and/or
on VAG 1551 scan
tool Possible malfunction cause

Malfunction repair
P0136 / 16520
O2 Sensor Circuit
Malfunction (Bank 1
Sensor 2) Harness connector for Oxygen Sensor (O2S)
behind Three Way Catalytic Converter (TWC) -
G130- (B1-S2) loose or corroded due to moisture
in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately Wiring connection to Oxygen Sensor (O2S)
behind Three Way Catalytic Converter (TWC) -
G130- (B1-S2) faulty, or sensor -G130- faulty

- Check O2S behind three way catalytic
converter -G130- (B1-S2) page 24
-
53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
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The malfunction "P0136 / 16520" is set, 123 sec after engine start, as soon as the signal voltage during a deceleration fuel
shut off is greater than 300 mV at a coolant temperature over 80 C (176 F) and 45 sec behind the probe heating after the
Three Way Catalytic Converter (TWC) is switched on. The length of the deceleration fuel shut off must be longer than 4 sec.
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01-42

Output on GST and/or
on VAG 1551 scan
tool Possible malfunction cause

Malfunction repair
P0138 / 16522
O2 Sensor Circuit High
Voltage (Bank 1
Sensor 2) Harness connector for Oxygen Sensor (O2S)
behind Three Way Catalytic Converter (TWC) -
G130- (B1-S2) loose or corroded due to moisture
in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S)
behind Three Way Catalytic Converter (TWC) -
G130- (B1-S2) faulty, or sensor -G130- faulty

- Check O2S behind three way catalytic
converter -G130- (B1-S2) page 24
-
53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
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01-43

Output on GST and/or
on VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0141 / 16525
O2 Sensor Heater Circuit
Malfunction (Bank 1
Sensor 2) Harness connector for Oxygen Sensor
(O2S) heater -Z29- (B1-S2) loose or
corroded due to moisture in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
MIL Status:
MIL lights up immediately
Wiring connection for Oxygen Sensor
(O2S) heater -Z29- (B1-S2) faulty, or heater
-Z29- faulty

- Check O2S heater -Z29- (B1-S2) page 24
-55


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
For troubleshooting
Display group 040
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:
The heater for the O2S behind the Three Way Catalytic Converter (TWC) is not switched on immediately at engine start, but
only when the calculated exhaust gas temperature exceeds 308 C (586 F)( Read measuring value block, display group
42, channel 1).
Pa
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) - Multi
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(MFI
)
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pair&id=AUDI.B5.FU01.01.1