light AUDI A6 1995 C5 / 2.G ATQ Engine Check DTC Memory And Erase DTC Memory Workshop Manual

01-18
Diagnostic Trouble Code (DTC) table

Notes:

When malfunctions occur in monitored sensors or components, Diagnostic Trouble Codes (DTCs) are stored in DTC
memory with a description of the malfunction type.
"E-Gas"-relevant malfunctions are also indicated in the instrument cluster by the warning lamp for Electronic Power
Control ("EPC warning lamp"); Notes for E-gas system Page 24
-134
.
Malfunctions that worsen emissions are also indicated by an exhaust warning lamp (MIL for output DTM) that is also
located in the instrument cluster. There are malfunctions that cause the exhaust warning lamp to light up immediately after
recognition. Malfunctions can also occur that do not cause the exhaust MIL to light up immediately, but only if malfunction
is recognized again after repeated engine starts.
The DTC table is organized by the 5 digit code at left.
If a stored DTC does not recur within the next 40 warm-up cycles, the DTC will be erased automatically.
Malfunctions that occur only sporadically (temporary malfunctions) are are identified by the letters "SP" (sporadic
malfunction) on the VAG1551 scan tool display. The word sporadic means "appearing or occurring at irregular intervals,
occasional".
Do not immediately replace components that the VAG1551/VAS5051 suggests are faulty, instead: Check wire
connections and harness connectors to these components according to wiring diagram. Also check Ground (GND)
connections according to wiring diagram. This is particularly valid when malfunctions are displayed as "sporadically
occurring" (SP).
Pa
ge 6 of 52 Check DTC Memor
y (function 02
) and Erase DTC Memor
y (function 05
)
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.01.2

01-26

DTC
DTC text
Corrective action
SAE
VAG


P0420 16804 Catalytic converter
system, bank 1,
Not effective enough
1)
Repair Manual, Engine Mechanical, Repair Group 26; Exhaust system
components, removing and installing - Generate readiness code Page 01
-82
. If the same malfunction is indicated
again, replace primary catalytic converter, bank 1.
P0421 16805 Primary catalytic
converter, bank 1,
Not effective enough
1)
Repair Manual, Engine Mechanical, Repair Group 26; Exhaust system
components, removing and installing - Generate readiness code Page 01
-82
. If the same malfunction is indicated
again, replace primary catalytic converter, bank 1.
1) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized
again after another engine start. Meaning of Malfunction Indicator Lamp (MIL) Page 01
-3 .
Important note:
The primary catalytic converters are located between the oxygen sensors of the appropriate cylinder bank. They are not
immediately visible after vehicle is raised; they are the two, slightly smaller catalytic converters located closer to the engine.
Pa
ge 15 of 52 Check DTC Memor
y (function 02
) and Erase DTC Memor
y (function 05
)
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.01.2

01-27

DTC
DTC text
Corrective action
SAE
VAG


P0430 16814 Catalytic converter
system, bank 2,
Not effective enough
1)
Repair Manual, Engine Mechanical, Repair Group 26; Exhaust system
components, removing and installing - Generate readiness code Page 01
-82
. If the same malfunction is indicated
again, replace primary catalytic converter, bank 2.
P0431 16815 Primary catalytic
converter, bank 2,
Not effective enough
1)
Repair Manual, Engine Mechanical, Repair Group 26; Exhaust system
components, removing and installing - Generate readiness code Page 01
-82
. If the same malfunction is indicated
again, replace primary catalytic converter, bank 2.
1) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized
again after another engine start. Meaning of Malfunction Indicator Lamp (MIL) Page 01
-3 .
Important note:
The primary catalytic converters are located between the oxygen sensors of the appropriate cylinder bank. They are not
immediately visible after vehicle is raised; they are the two, slightly smaller catalytic converters located closer to the engine.
Pa
ge 16 of 52 Check DTC Memor
y (function 02
) and Erase DTC Memor
y (function 05
)
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.01.2

01-30

DTC
DTC text
Corrective action
SAE
VAG


P0571 16955 Brake light switch -F-
Implausible signal - Check brake light switch and brake pedal switch Page 24
-178
P0601 16985
Control module faulty
1)
- replacing Engine Control Module (ECM) Page 24
-21
P0604 16988
Control module faulty
1)

P0605 16989
Control module faulty1)

P1102 17510 Bank 1, sensor 1, heating circuit
Short circuit to B+
1) - Check oxygen sensor heating Page 24
-116
P1105 17513 Bank 2, sensor 1, heating circuit
Short circuit to B+
1)
P1107 17515 Bank 2, sensor 1, heating circuit
Short circuit to B+1)

P1110 17518 Bank 2, sensor 2, heating circuit
Short circuit to B+1)

1) For these malfunctions, ECM does not switch on the Malfunction Indicator Lamp (MIL) unless malfunction is recognized
again after another engine start. Meaning of Malfunction Indicator Lamp (MIL) Page 01
-3 .
Pa
ge 19 of 52 Check DTC Memor
y (function 02
) and Erase DTC Memor
y (function 05
)
11/23/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU05.01.2