Page 65 of 78
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- Connect multimeter for voltage measurement to
Ground (GND) and to one terminal of the
following fuses in the fuse holder.
Fuse
Specified value at one of the
terminals
S228 approx. battery voltage
S229 approx. battery voltage
S234 approx. battery voltage
If specified values are not obtained:
- Repeat test at another terminal of fuse socket.
If specified values are not obtained again:
- Check wire connections.
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder If no malfunctions are detected:
- Replace Fuel Pump (FP) relay -J17-.
- Re-insert the fuses.
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Page 67 of 78
24-57
Test requirements:
Coolant Temperature at least 80 C.
Electrical consumers switched off (radiator
fan must NOT run during test).
A/C switched off.
Fuse for Mass Air Flow (MAF) sensor OK
Electrical Wiring Diagrams, Troubleshooting &
Component Locations binder
Checking function
- 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 -4- to select "Initiate basic setting" and press -Q-
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Page 73 of 78
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Voltage supply for Mass Air Flow (MAF)
sensor, checking
- Disconnect connector from Mass Air Flow (MAF)
sensor.
Note:
Voltage is supplied to Mass Air Flow (MAF) sensor from Fuel Pump (FP)
relay.
If specified value is not obtained:
Electrical Wiring Diagrams, Troubleshooting & Component Locations
binder - Connect multimeter for voltage measurement as follows.Harness connector
Terminal
Measure to
3 Engine Ground (GND)
- Operate starter briefly.
Specification: approx. battery voltage
- Check wire connection from terminal 3 of connector to Fuel Pump (FP)
relay via fuse for open circuit and short circuit to Ground (GND):
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Page 75 of 78
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Check wire connections for Mass Air Flow
(MAF) sensor
Note:
Signal wire is also checked during wire test.
- Connect VAG1598/31 test box at wiring harness
to ECM, do not connect ECM Page 24
-17
.
If wire connection is OK: - 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 53
2 27
4 29
- Repair open circuit or short circuit if necessary.
- Also check all wires for short circuit to each other.
- Replace Mass Air Flow (MAF) sensor -G70-.
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