engine AUDI A6 1995 C5 / 2.G ATQ Engine Motronic Injection System Servicing User Guide

24-21

Engine Control Module (ECM), replacing


Special Tools and Equipment

Removing
VAS5051 with VAG5051/1
orVAG1551 with VAG1551/3B
- Connect VAS5051 tester or VAG1551 scan tool and select the control
module for engine electronics using "address word" 01 Page 01
-9 .
Ignition must remain switched on for this.
3B0907551BA
2.8l V6/5V
G
0003
Coding 07252
WSC 12345

VAG1551 Scan Tool (ST) display indicates control module identification,
e.g.:
- First, always allow display of control module identification and print it
out Page 01
-11
.
- Compare coding with coding versions Page 01
-73
.
- Switch ignition off.
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Installing
Installation is reverse of removal, noting the following:
Important note:
After installing new Engine Control Module (ECM), the following work
steps must be performed:
- Check DTC memory and erase it if necessary Page 01
-15
.
- Perform adaptation of the Throttle Valve Control Module -J338- Page
24
-142
. - Using a screwdriver, carefully pry off retaining bracket (arrow).
- Disengage locking lugs and remove control module connector.
- Remove Engine Control Module (ECM).
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- Observe notes for coding new Engine Control
Module (ECM) Page 01
-71
.
- For vehicles with cruise control (discernable at
steering column), switch this free in ECM:

Repair Manual, Electrical Equipment, Repair
Group 01; On Board Diagnostic (OBD) of cruise control system; Cruise control system, checking

- Adapt immobilizer to Engine Control Module
(ECM):

Repair Manual, Electrical Equipment, Repair
Group 01; On Board Diagnostic (OBD) of immobilizer after replacing Engine Control Module (ECM)

- For vehicles with automatic transmission, the
kick down function must be learned Page 24
-
161
.
- Generate readiness code Page 01
-82
.

Note:
In the first adaptation phase during engine basic
setting, it is possible that idle will be rough and
vehicle may shake lightly in drive mode.
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Notes:

Idle speed cannot be adjusted.
Idle speed is checked during basic setting of
the engine.
During basic setting, the Evaporative Emission
(EVAP) canister purge regulator valve (EVAP
valve -N80-) is closed and the A/C compressor
is switched off

Test sequence

- Check DTC Memory Page 01
-15
. There must
not be any DTCs stored, repair malfunctions if
necessary, erase DTC memory, switch engine
off and start again, road test vehicle and check
DTC memory again as a control measure.

- Let engine continue to run at idle.

CAUTION!

The electric cooling fan must not run. Rapid data transfer
HELP
Select function XX

When indicated on display:
- Press buttons -0- and -4- to select "Initiate basic setting" and press -Q-
button to confirm input.
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Basic Settin
g
Q
Input display 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.
System in Basic Setting 56
1
2
3
4

When indicated on display:
- Check whether the engine speed in display field 1 (actual engine speed) is within
tolerated range.

Display fields

1 2 3 4
Display group 056: Idle stabilization with engine at idle and operating temperature
Display
xxx /min
xxx /min x.x % X X X X X
Indicated
Engine speed (actual)
Engine speed
(specified) Idle control
Torque
change Operating conditions
Specified
value 720 to 820 RPM
1)
630 to 730 RPM 2) 770 RPM
1)
680 RPM 2) -5 to 5 % 0 0 0 0 0
Notes
If specified value is not obtained
Page 24
-29

Significance of
numbers
Page 24
-29

1) Front Wheel Drive Vehicles
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Notes:

Engine speed in display field 1 (actual engine
speed) is the current engine speed.
Engine speed in display field 2 (specified
engine speed) is a theoretical engine speed
calculated by the ECM.
At idle, the ECM always attempts to adapt the
engine speed (actual) to the specified engine
speed (specified).
This means that the engine speed (actual) must
always approximately match the engine speed
(specified) at idle.
Display fields 3 and 4 provide information, but
are not relevant for checking idle speed.
If specified value is obtained:

-
Press button.
Rapid data transfer
HELP
Select function XX

Indicated on display (function selection):
If specified value is not obtained:
- Check DTC memory again Page 01
-15
.
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24-30

Fuel pressure regulator and residual
pressure, checking


Note:
Fuel pressure regulator regulates fuel pressure
according to intake manifold pressure. This
ensures that the pressure drop at the fuel
injectors remains the same for each speed and
load range of the engine.

Special Tools and Equipment

Test requirements:
Repair Manual, Fuel Supply System, Repair Group 20; Fuel supply Front Wheel Drive or fuel supply
- All Wheel Drive

VAG 1318 with VAG 1318/7 adapter, VAG 1318/8 pressure hose with
connectors and VAG 1318/15 adapter Fuel Pump (FP) OK, checking Page 24
-49
.
Fuel Pump (FP) OK, checking: Fuel filter OK Battery voltage at least 12.7 V Vehicles with automatic transmission Selector lever in P or N.
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WARNING!

Fuel system is under pressure! Place a cloth
around the connection point before opening
system. Then release pressure by carefully
loosening connection point.

Checking system pressure - Remove engine cover (arrows).

Note:
If fuel should escape at the vacuum connection of the pressure regulator
during the following pressure test, replace pressure regulator. - Connect VAG1318 pressure gauge using adapters
VAG1318/7, /1318/8 pressure hose with connectors and 1318/15
adapter in supply line.
- Disconnect vacuum hose from pressure regulator to intake manifold at
pressure regulator and seal line.
- Start engine and let run at idle.
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- Measure fuel pressure.


Specification: 3.8 to 4.2 bar

- If the specified value is not reached, replace
pressure regulator on a trial basis and repeat
pressure test.

- If the specified value is not reached again, check
Fuel Pump (FP) or supply line for damage (e.g.
pinched areas) and replace if necessary.

- If the specified value is exceeded, check return
line for damage (e.g. pinched areas) and replace
if necessary.

Note:
During the following test, the engine must not run
for an unnecessarily long period of time with the
vacuum hose removed. Otherwise, the higher
fuel pressure can cause enrichment of the fuel to
air ratio, which under some circumstances can
cause the oxygen sensor control limits to be
exceeded, causing a DTC to be stored.

- Start engine and let run at idle.

-
Switch of electrical consumers (A/C system
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- Fuel pressure must drop by approx. 0.5 bar
when connecting the vacuum hose.

If the pressure change does not occur, the
following tests must be performed:


Check vacuum hose for tears and
damage.

Check vacuum hose at intake manifold for
throughput by disconnecting from pressure
regulator and blowing into it.

- If no leaks can be detected and if the vacuum
hose has throughput, replace the pressure
regulator.

Checking residual pressure

- Residual pressure 10 minutes after switching
engine off (minimum pressure).

Specified value with a cold engine: approx.
2.2 bar

Specified value with the engine at operating
temperature: approx. 3.0 bar
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