check engine AUDI A6 1998 C5 / 2.G ATQ Engine Ignition System Checking Owner's Guide

28-49
If specified values are not obtained:

Checking wire connections between
Camshaft Position (CMP) sensor and Engine
Control Module (ECM)

- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.

Camshaft Position (CMP) Sensor 2 -G40- (bank 2)
Camshaft Position (CMP) Sensor 2 -G163- (bank 1) - Check the following wire connections for open circuit and short circuit
to Ground (GND) and B+: Harness connector
Terminal
VAG1598/31 test box
Socket
1 (B+) 98
2 (signal) 86
3 (Ground -GND-) 108
Harness connector
Terminal
VAG1598/31 test box
Socket
1 (B+) 98
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- Repair open circuit or short circuit if
necessary.

- If, after erasing DTC memory for the sake of the
test, a DTC relating to the Camshaft Position
(CMP) sensor (hall sensor) is indicated again,
even though all previous tests were OK, the
following malfunction is possible:


Shutter wheel for Camshaft Position (CMP)
sensor is not aligned properly.

Check phase position of Camshaft Position
(CMP) sensor

- 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.
Read Measurin
g Value Block
Q
Input display group number XXX

When indicated on display:
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Display fields

1 2 3 4
Display group 093: Phase position of Camshaft Position (CMP) sensor bank 1 and bank 2 with engine at idle.
Display xxx /min xx %
KW
KW
Indicated Engine
speed Engine
load Phase position
Bank 1 Phase position
Bank 2
Functional
range 630 to 6800
RPM 12 to 100
% -20 to 15 KW
-20 to 15 KW
Specified
value 720 to 820
RPM
1)
630 to 730
RPM 2) 12 to 26
% -20 to 15 KW
-20 to 15 KW
Notes

If specified values are not reached, unscrew Camshaft Position (CMP)
sensor and check whether shutter wheel is mounted properly at camshaft
(if mounted improperly, locking lug will get squished when mounting bolt is
tightened).
Repair Manual, Engine, Mechanical, Repair Group 13, removing and installing
toothed belt - Also check engine timing
1) Front Wheel Drive Vehicles 2) All-Wheel Drive Vehicles
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Misfire recognition, checking


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"
function 08. Press -Q- button to confirm input.
Read Measuring Value Block
Q
Input displa
y group number XXX

When indicated on display:
- Press buttons -0-, -1- and -4- to select "display group number 014" and
press -Q- button to confirm input.
Read Measuring Value Block 14
1
2
3
4

When indicated on display:
- Check misfire recognition in display fields 3 and 4.
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Display fields

1 2 3 4
Display group 014: Misfire recognition
Display xxxx/min xxx %
xxx
---
Indicated Engine speed
(RPM) Load
Number of combustion misfires
Misfire
recognition
Functional
range 670 to 6800
RPM 12 to
100 %
activated
locked
Specified
value 720 to 820
RPM
1)
630 to 730
RPM 2) 12 to 26
% 0 to 12
activated
Notes
If the specified value is exceeded: Check combustion
misfires of the individual cylinders Page 28
-54


1) Front Wheel Drive Vehicles 2) All-Wheel Drive Vehicles
If specified value is obtained:

-
Press button.Rapid data transfer
HELP

Indicated on display (function selection):
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Evaluation display group 014, display field 3 and display group 015 and 016, display fields 1, 2 and 3
Indicated on
display
Possible cause
Corrective action
greater than 15

spark plug defective
spark plug connector defective
Ignition coil or power output stage faulty- Check spark plugs and ignition wires with connectors.
- Check ignition coils and power output stages Page
28
-7


Fuel injector faulty- Check fuel injectors Page 24
-36


Poor compression of one or more
cylinders
Repair Manual, Engine Mechanical, Repair Group
15 - Check compression pressure:
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