1996 AUDI A4 engine coolant

01-167
Notes on display field 1:

The Engine Coolant Temperature (ECT) sensor is a temperature-dependent resistor. If the sensor signal is falsified by e.g.
dampness in the harness connection (effect as with resistors connected in parallel), this falsification can lie in a range that
is not recognized by the DTC memory.
If a malfunction relating to the Engine Coolant Temperature (ECT) sensor is stored, a coolant temperature of 20 C (68
F) is displayed in the measuring block at engine start. 10 C (50 F) is added to this for each minute of engine operation.
The maximum replacement value is 85 C (185 F).
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01-184
Notes on display field 3

The oxygen sensor learning requirement diagnosis shows what oxygen sensor learning value was checked in the learning
process.
If diagnosis is successful, the corresponding value is set to "1", independently of whether the diagnosis was recognized as
OK or not OK.
If an "oxygen sensor learning requirement diagnosis" value is set to "1" in display field 3, but the corresponding value of
the "oxygen sensor learning requirement display" is not set to "1" in display field 4, the diagnosis was carried out but not
recognized as OK by the Engine Control Module (ECM). The " oxygen sensor learning requirement diagnosis" is now
continued.
The oxygen sensor learning requirement diagnosis is reset to "0" every time there is a start with a coolant temperature
less than 40 C (104 F).
X
X
X
X
X
X
X
X
Meaning of 8-digit oxygen sensor learning requirement diagnosis

1 = Idle (bank 1)

2 = Idle (bank 2)

3 = Partial throttle 1 (bank 1)

4 = Partial throttle 1 (bank 2)

5 = Partial throttle 2 (bank 1)

6 = Partial throttle 2 (bank 2)

7 = Partial throttle 3 (bank 1)
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01-185
Notes on display field 4
Display field 4 (learning requirement display) shows the learning range (display field 2) for which learning is required.
Requirement for learning:

No malfunction stored in DTC memory
Engine speed at idle 650-900 RPM and/or 1500-3000 RPM
Coolant temperature 80-110 C (176-230 F) (if learning does not start immediately after this requirement, step on the
throttle).
Learning is prohibited:

With uneven idle (hunting), during acceleration, at wide open throttle
If malfunctions are stored in the DTC memory (not with sporadic malfunctions)
If differences of 9% are obtained between the richest and leanest oxygen sensor learning value of one display group. If a
9% difference is obtained, continued learning of the learning range involved is discontinued. The learning requirement
display of this learning range can not be 1 display groups 005 and/or 006.
Learning starts 20 sec. after initiation of "Basic Setting" function 04 and/or 2 to 4 min. after each start at a which the coolant
temperature is less than 40 C (104 F). The following listing shows when the request for new learning (learning requirement) is forced:
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01-191

Display
fields Display on VAG 1551 scan tool
Malfunction cause
Malfunction repair
3/4 Display does not fluctuate-constant
between 0.0 - 0.3 V and/or between
0.6 - 0.9 V
Fuel injector faulty- Check fuel injectors page 24
-29

Spark plug faultyLarge intake air leak Engine Coolant Temperature
(ECT) sensor -G62- faulty EVAP canister purge
regulator valve -N80- - Check spark plug
- Repair cause
- Check DTC memory page 01
-13

and/or check -G62-
- Check using output diagnostic test
mode page 01
-145
and/or check -
N80-

Heated Oxygen Sensor
(HO2S) -G39- faulty or dirty Oxygen Sensor (O2S) heater
-Z19- does not function - Check DTC memory page 01
-13

and/or check -G39-
- Check -Z19- page 24
-49

Fuel system pressure too
high or too low - Check fuel pressure regulator and
residual pressure page 24
-20


Constant 2.550 V Short to positive (B+) through:
Heated Oxygen Sensor
(HO2S) -G39- wiring Engine Control Module
(ECM) -J192- - Check -G39- page 24
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01-199
Display group 017
Note:
If in display group 029, display field 1, the value of the EGR system throughput diagnosis is not set to "0" during the
regeneration of the "readiness code," and/or a malfunction relating to the exhaust system is stored in the DTC memory,
display group 017 is used to carry out a selective diagnosis.
During cold start at idle, -10 C to 30 C (14 to 86 F), and during "Basic Setting" function 04, no exhaust gas recirculation
takes place. Since exhaust gas recirculation is switched off automatically during "Basic Setting" function 04, diagnosis of EGR
throughput is evaluated only in "Read Measuring Value Block." function 08. If diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the flow through the EGR system after each
start. The diagnostic conditions are only reached during a trip at 80-100 km/h (50-63 mph) in 4th or 5 gear and/or with selector
lever in the "D"position, preferably in 4th gear position. If the diagnostic conditions are fulfilled, the diagnosis is active. In order
to get a diagnostic result, the vehicle must be driven approx. 1-1/2 to 5 minutes under the diagnostic conditions. However, the
diagnosis is only considered OK when the EGR temperature (display field 4) is greater than 50 C (122 F) during the reading
time (display field 2). Diagnosis of the EGR flow (exhaust gas recirculation quantity) is active as soon as the following diagnostic conditions are
fulfilled:

Coolant temperature: greater than 8 C (46 F) ( display group 001) Vehicle speed: constant drive
Engine speed: 2000-3000 RPM ( display group 003) Engine load: 30-60%
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01-204
Display group 022
Notes:
Display group 022 should only be considered on vehicles with traction control (ATC).
Vehicles with traction control (ATC) can be recognized by the ATC indicator light in the instrument cluster and/or ABS (ATC)
On Board Diagnostic (OBD).
Repair Manual, Brake System On Board Diagnostic (OBD), Repair Group 01.

The wheel slip information for traction control (ATC) is calculated in the ABS control module. If slip is recognized, the ABS
control module requests a reduction in torque from the Engine Control Module (ECM). This torque reduction is divided into 12
reducing stages.
With a cold engine, coolant temperature less than 20 C (68 F), the reduction of engine torque is obtained:
With retarded ignition timing angle for lower reducing stages (1-5)
By brief shut-off of individual fuel injectors for higher reducing stages (6-12)
If the engine is warm, coolant temperature greater than 40 C (104 F), the engine torque reduction is obtained only by briefly
switching off individual fuel injectors.
Display shows
Display/specified value
Designation
Basic setting 22
1 2 3 4 0 - 12 1 = Reducing stages

_._ crankshaft
2 = Ignition timing point retarded by ATC (only with cold engine)
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01-235
Notes on display field 3 and 4:
Value "0" = Diagnosis condition not fulfilled.
Value "1" = Diagnosis condition fulfilled. X
X
X
X
X
X
X
X
Meaning of 8-digit "Diagnosis condition 1"

1 = Coolant temperature: 70 - 110 C ( display group 001)
2 = Engine load: 27 - 66% ( display group 003)
3 = Engine speed: 1800 - 2700 RPM ( display group 003)
4 = Fuel throughput after engine start
[only fulfilled after approx. 3 min. trip (no idle) after start]

5 = No fuel enrichment
(during diagnosis no enrichment can occur display group 019)
6 = Closed throttle position switch open ( display group 008)
7 = Oxygen sensor control, bank 2 active ( display group 008)
8 = Oxygen sensor control, bank 1 active ( display group 007)
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01-244
Display group 099 Display
shows Display/specified
value Designation/diagnosis
Basic
setting 99
1 2 3 4 ... RPM 1 = Momentary engine speed Display group 003, display field 1 ...% 2 = Momentary engine load display group 003, display field 2
... C
3 = Coolant temperature display group 001, display field 1

-Control OFF
and/or
-Control ON
4 = Oxygen sensor control OFF in "Basic Setting" function 04; Oxygen sensor control
ON in "Read Measuring Value Block" function 08
Notes on display field 4:

For defined troubleshooting, the oxygen sensor control is switched off when display group 099 is selected under "Basic
Setting" function 04, and switched on when display group 099 is selected under "Read Measuring Value Block"function
08. When leaving "Basic Setting" function 04, oxygen sensor control is automatically active again.
You can switch back and forth between "Basic Setting" function 04 and "Read Measuring Value Block" function 08 by
pressing buttons -4- and -8- on the VAG 1551 scan tool.
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