1999 AUDI A4 AHA Engine Multiport Fuel Injection And Ignition System Workshop Manual

Diagnostic Trouble Code (DTC) memory has
been erased, or ECM was disconnected,
generate new readiness code page 01
-73
.
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24-75

Engine Coolant Temperature (ECT)
sensor, checking


Required special tools and test equipment

VAG1551 or VAG1552 Scan Tool (ST) with
VAG1551/3 adapter cable
VAG1598/22 test box
Multimeter US1119 (Fluke 83 or equivalent)
VW1594 connector test kit
Wiring diagram

Test requirements
Engine cold
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Checking

- Connect VAG1551 or VAG1552 scan tool and
press buttons -0- and -1- to insert "Engine
Electronics" address word 01 (with ignition
switched on) page 01
-8 .
Rapid data transfer
HELP
Select function XX

Indicated on display
- Press buttons -0- and -8- to select "Read Measuring Value Block"
function 08, and press -Q- button to confirm input.
Read Measurin
g Value Block
HELP
Input displa
y group number XXX

Indicated on display
- Press buttons -0-, -0- and -4- to input display group number 4 (004),
and press -Q- button to confirm input.
Read Measuring Value Block 4 1 2 3 4

Indicated on display (1-4 = display fields)
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- Compare display with specified value for engine
coolant temperature sensor (display field 3):

Display fields

1 2 3 4
Display group 4: General engine data
Display xxx RPM xx.xxx V
xxx.x C
xxx.x C
Indicates Engine
speed
(in 40 RPM
steps) Battery Positive
Voltage (B+) Engine coolant temperature Intake air
temperature
Range 0 - 6800
RPM 0.000 - 16.500 V -46.5 to 141.0 -46.5 to 141.0
Specified
value 0 RPM 10.000 - 14.500 V approx. ambient temperature 1), 2) ---

--- --- If specified value is not attained page 24
-79
,
Evaluation of display group 4
---
1) After a long standing period (approx. 12 hours). 2) If indicated temperature deviates significantly from the ambient temperature, check ECT sensor wiring for resistance or
open circuits.
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24-78

Continuation

- Start engine and let run at idle.

Temperature value must increase evenly
If NOT:

-
Press button.

- Press buttons -0- and -6- to select "End Output"
function 06, and press -Q- button to confirm
input.

- Switch ignition off.

- Replace Engine Coolant Temperature (ECT)
sensor -G62-.

Notes:

Temperature is displayed in increments of 1.5
C.

If malfunctions occur within certain temperature
ranges while the engine is running, and the
temperature values do not increase without
interruption, the temperature signal is
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intermittently interrupted and the sensor must
be replaced.
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24-79
Evaluation of display group 4 Display group: 4


Display field: 3
Possible malfunction cause
Corrective action
approx. -46.5 C
Open circuit or short circuit in wiring to B+ - Check wiring page 24
-79
approx. 141.0 C
Short circuit to Ground

Checking wiring

- Connect VAG1598/22 test box to ECM harness
connector page 01
-67
.

- Disconnect 4-pin connector from ECT sensor -
G62-.

- Check wiring resistance for open circuit between ECM/test box and 4-pin
ECT sensor connector.

Connector terminal 1 to ECM/test box socket 53
Connector terminal 3 to ECM/test box socket 67
Specified value: max. 1.5
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- Check wiring for short circuit between ECM/test box and 4-pin harness
connector according to wiring diagram.

Connector terminal 1 to vehicle Ground
Connector terminal 1 to ECM/test box socket 67
Connector terminal 1 to terminal 3
Connector terminal 3 to vehicle Ground
Specified value:
- Check wiring between ECM and 4-pin harness connector for short
circuit to battery B+.

Connector terminal 1 to vehicle Ground
Connector terminal 3 to vehicle Ground
Specified value: 0 volts
Pa
ge 104 of 166 Motronic Multi
port Fuel In
jection
(MFI
) and i
gnition s
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11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU03.24.1