wheel AUDI A8 1997 D2 / 1.G ATQ Engine Additional Signals Testing Workshop Manual

24-169

Test sequence

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Engine must run at idle for this.

WARNING!

Observe safety precautions to reduce the risk
of accidents during road test Page 24
-1 .
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 displa
y group number XXX

When indicated on display:
- Press buttons -0-, -0- and -5- to select "display group number 005" and
press -Q- button to confirm input.
Read Measuring Value Block 5
1
2
3
4

Indicated on display:
- Determining via road test whether vehicle speed is displayed in display
field 3.
- If vehicle speed is not display, lift vehicle -if possible using a vehicle lift-
until front left wheel is free.
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- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

- Connect VAG1527B voltage tester to sockets 3
(B+) and 54 (VSS) of VAG1598/31 test box.

- Switch ignition on and turn front left wheel by
hand.


LED must blink (very brief blink signal).
If LED does not blink:

- Check the following wire connection for open
circuit and short circuit to Ground (GND) and B+:

Test box
VAG1598/31
Socket
Instrument cluster

Terminal
54 Electrical Wiring Diagrams,
Troubleshooting & Component
Locations binder

- Repair open circuit or short circuit if
necessary.
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24-175

A/C system signal, checking

The A/C system signal notifies the Engine
Control Module (ECM), that the A/C system
requires a higher idle speed to achieve the
desired interior temperature (regardless of
whether heating or cooling is required).
The increase in idle speed based on presence of
the A/C system signal is control module
dependent and occurs only in vehicles with All
Wheel Drive (AWD) and manual transmission.

Test sequence

- Connect VAS5051 tester or VAG1551 scan tool
and select the control module for engine
electronics using "address word" 01 Page 01
-
9 .

Engine must run at idle for this.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.
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If specified values are not obtained:
Read Measuring Value Block
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -0-, -5- and -6- to select "display group number 056" and press -Q-
button to confirm input.
- Switch on A/C system, press "Auto" button and select the lowest temperature.
- Check indications in display field 3 and 4.

Display fields

1 2 3 4
Display group 056: Idle stabilization with engine at idle and operating temperature
Display xxx /min xxx /min
---
---
Indicated Engine speed (actual) Engine speed (specified)
A/C readiness
A/C compressor
Functional range

A/C - LOW
A/C - HIGH Compr. OFF
Compr. ON
Specified value
720 to 820 RPM
1)
630 to 730 RPM 2) 760 RPM
1)
680 RPM 2) A/C - HIGH
Compr. ON
1) Front Wheel Drive Vehicles 2) All-Wheel Drive Vehicles
- Connect VAG1598/31 test box at wiring harness to ECM, do not connect ECM Page 24
-17
.
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24-190

Rough terrain signal from ABS/EDL
control module, checking


Notes:

When the ABS/EDL control module recognizes
that a wheel is spinning, the ABS/EDL control
module generates the rough terrain signal.
When the Engine Control Module (ECM)
recognizes the rough terrain signal, combustion
misfire recognition is switched off in the Engine
Control Module (ECM).
Only check the rough terrain signal if the
malfunction "18014 (P1606) rough terrain
info/engine torque from ABS cont. mod.
Electrical malfunction in circuit" is stored DTC
memory.It is possible that the malfunction
"Combustion misfire" is also stored in DTC
memory as a side effect and it can be
disregarded.
The wire connection and rough terrain signal
are monitored by the Engine Control Module
(ECM).
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