1998 AUDI A4 engine coolant

01-16
Diagnostic Trouble Code (DTC) overview

Notes:

The Diagnostic Trouble Code (DTC) overview is organized according to SAE and VAG trouble codes.
Diagnostic Trouble Codes (DTC) for which the MIL is not switched on by the engine control module after a malfunction is
recognized are identified with the MIL switching condition "off."
Diagnostic Trouble Codes (DTC) for which the MIL is switched on by the engine control module immediately after a
malfunction is recognized are identified with the MIL switching condition "immediately."
Diagnostic Trouble Codes (DTC) for which the MIL is not switched on until the malfunction is recognized after taking 2
trips (FTP 72) are identified with the MIL switching condition "2 Trips."
Always repair the malfunctions with the MIL switching condition "immediately" first, and then the malfunctions with the
switching condition "2 Trips."
Diagnostic Trouble Code
(DTC) Malfunction text
MIL switching
condition
SAE
VAG
P0102 16486 Mass or Volume Air Flow Circuit Low Input immediately
P0103 16487 Mass or Volume Air Flow Circuit High Input immediately
P0116 16500 Engine Coolant Temperature Circuit Range/Performance
Problem immediately
P0117 16501 Engine Coolant Temperature Circuit Low Input immediately
Pa
ge 26 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
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P0118 16502 Engine Coolant Temperature Circuit High Input immediately
P0120 16504 Throttle Position Sensor A Circuit Malfunction immediately
P0121 16505 Throttle Position Sensor A Circuit Range/Performance
Problem immediately
Pa
ge 27 of 366 On Board Dia
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(OBD
) - Multi
port Fuel In
jection
(MFI
)
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play?action=Goto&t
yp
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01-29

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0116 / 16500
Engine Coolant Temperature
Circuit Range/Performance
Problem Harness connector on Engine Coolant
Temperature (ECT) sensor -G62- loose or
corroded due to dampness in the harness
connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 28
-7

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after
test drive check DTC memory again
MIL Status:
MIL lights up immediately Wiring conection to Engine Coolant
Temperature (ECT) sensor -G62- faulty,
or sensor -G62- faulty

- Engine Coolant Temperature (ECT)
sensor -G62-, checking page 28
-25


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after
test drive check DTC memory again
For troubleshooting Display
groups 000, 001
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The malfunction "P0116 / 16500" is set as soon as the coolant temperature lies under 55 C (131 F) after engine start, but
18 minutes later the temperature has not risen to over 70 C (158 F).
Pa
ge 41 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-30

Output on GST and/or
on VAG 1551 scan tool
Possible malfunction cause

Malfunction repair
P0117 / 16501
Engine Coolant
Temperature Circuit
Low Input Harness connector on Engine Coolant
Temperature (ECT) sensor -G62- loose or
corroded due to dampness in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 28
-7

Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
MIL Status:
MIL lights up
immediately Wiring connection to Engine Coolant
Temperature (ECT) sensor -G62- faulty, or
sensor -G62- faulty

- Engine Coolant Temperature (ECT)
sensor -G62-, checking page 28
-25


Malfunction cause found: Yes
No

- Erase DTC memory, test drive, after test
drive check DTC memory again
For troubleshooting
Display groups 000,
001
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:
The malfunction "P0117 / 16501" is set as soon as the signal voltage drops below 0.10 volts for longer than 1 sec when
ignition is switched on (corresponds to a coolant temperature over 200 C (392 F).
Pa
ge 42 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-31

Output on GST and/or
on VAG 1551 scan tool
Possible malfunction cause

Malfunction repair
P0118 / 16502
Engine Coolant
Temperature Circuit
High Input Harness connector on Engine Coolant
Temperature (ECT) sensor -G62- loose or
corroded due to moisture in the harness
connector

- Check harness connector for tight fit and
contact corrosion, if necessary reconnect
and/or clean, installation location page 28
-7

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
MIL Status:
MIL lights up
immediately Wiring connection to Engine Coolant
Temperature (ECT) sensor -G62- faulty, or
sensor -G62- faulty

- Check Engine Coolant Temperature
(ECT) sensor -G62- page 28
-25


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and check
DTC memory again
For troubleshooting
Display groups 000,
001
Engine Control Module (ECM) -J192-
faulty

- Replace and code engine control module
page 01
-265
erase DTC memory and
test drive check DTC memory
Notes:
The malfunction "P0118 / 16502" is set as soon as the signal voltage is over 4.98 volts for longer than 1 sec with ignition on
(corresponds to a coolant temperature below -50 C (-58 F)).
Pa
ge 43 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-33

Output on GST and/or on
VAG 1551 scan tool Possible malfunction cause

Malfunction repair
P0121 / 16505
Throttle Position Sensor A
Circuit Range/ Performance
Problem Harness connector on Throttle Position
(TP) sensor -G69- loose or corroded due to
moisture in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up immediately Harness connector on Mass Air Flow
(MAF) sensor -G70- loose or corroded due to
moisture in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting Display
group 002
Throttle Position (TP) sensor -G69- loose,
incorrectly adjusted or shaft connection
eccentric

- Check and adjust throttle position
sensor -G69- page 24
-77

Notes:
The malfunction "P0121 / 16505" is set at a coolant temperature of over 70 C (158 F), engine speed between 1500 RPM
and 3500 RPM for longer than 2 seconds and an engine load over 66% (Mass Air Flow sensor signal) as soon as the sensor
signal voltage is less than 0.96 volts (corresponds to a throttle opening less than 12 ).
Pa
ge 45 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

The malfunction "P0136 / 16520" is set, 123 sec after engine start, as soon as the signal voltage during a deceleration fuel
shut off is greater than 300 mV at a coolant temperature over 80 C (176 F) and 45 sec behind the probe heating after the
Three Way Catalytic Converter (TWC) is switched on. The length of the deceleration fuel shut off must be longer than 4 sec.
Pa
ge 56 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1

01-49

Output on GST
and/or on VAG 1551
scan tool Possible malfunction cause

Malfunction repair
P0156 / 16540
O2 Sensor Circuit
Malfunction (Bank 2
Sensor 2) Harness connector for Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) loose or corroded due to moisture
in the harness connector

- Check harness connector for tight fit
and contact corrosion, if necessary
reconnect and/or clean, installation
location page 24
-1

Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
MIL Status:
MIL lights up
immediately
Wiring connection to Oxygen Sensor (O2S) 2
behind Three Way Catalytic Converter (TWC) -
G131- (B2-S2) faulty, or sensor -G131- faulty

- Check O2S 2 behind three way
catalytic converter -G131- (B2-S2)
page 24
-53


Malfunction cause found: Yes
No

- Erase DTC memory, test drive and
check DTC memory again
For troubleshooting
Display group 041
Engine Control Module (ECM) -J192- faulty

- Replace and code engine control
module page 01
-265
erase DTC
memory and test drive check DTC
memory
Notes:
The malfunction "P0156 / 16540" is set 123 sec after engine start, at a coolant temperature over 80 C (176 F) and 45 sec
Pa
ge 65 of 366 On Board Dia
gnostic
(OBD
) - Multi
port Fuel In
jection
(MFI
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU01.01.1