1996 AUDI A4 catalytic converter

01-74

DTC
Description of malfunction
Corrective action
SAE
VAG


P1851 18259 Data Bus Powertrain
Missing Message from Brake Contr
Repair Manual, Brake System On Board Diagnostic (OBD), Repair
Group 01, checking DTC memory of ABS control module
- Check DTC memory of ABS control module
- Check data exchange between Engine-/ABS-
/Transmission control
module Page 24
-201

P1853 18261 Data Bus Powertrain
Unplausible Message from Brake
Contr.
P1854 18262 Data Bus Powertrain
Hardware Defective
P3262 19718 Exhaust bank 1/2 oxygen sensors
behind catalytic converter
mixed up - Check harness connectors for oxygen sensors and check installed
position of oxygen sensors behind catalytic converter. 1) With this malfunction the EPC (Electronic Power Control) Malfunction Indicator Light (MIL) in the instrument cluster is
switched on by the ECM. Significance of EPC malfunction indicator light Page 24
-142
.
2) With this malfunction the exhaust Malfunction Indicator Light (MIL) is only switched on by the ECM, if the malfunction is
recognized after the engine has been restarted. Significance of MIL Page 01
-3 .
Pa
ge 91 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-103

X
X
X
X
X
X
X
X
Notes for display group 086 display field 1 (Ready-Bits)

1 = Three Way Catalytic Converter (TWC) (diagnostic of catalytic converter)

Display 0 = ready
Display 1 = not ready (Readiness code generating Page 01
-105
)

2 = TWC Catalytic Converter (not available/always "0")

3 = EVAP system (0 = ready)

Display 0 = ready
Display 1 = not ready (Readiness code generating Page 01
-105
)

4 = Secondary Air Injection (AIR) System

Display 0 = ready
Display 1 = not ready (Readiness code generating Page 01
-105
)

5 = Climate Control (diagnosis not applicable/always "0")

6 = Oxygen sensors

Display 0 = ready
Display 1 = not ready (Readiness code generating Page 01
-105
)

7 = Oxygen sensor (O2S) heater

Display 0 = ready
Pa
ge 124 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-120

Work step 8: Diagnosis oxygen sensor aging
before catalytic converter

Test requirements

Engine running at 1900 - 2200 RPM
System in Basic Settin
g
Q
Input display group number XXX

Indicated on display
- Press buttons -0-, -3- and -4- to select "display group number 034" and
confirm with -Q- button.
System in Basic Setting 34
1
2
3
4

Indicated on display
- Check specified value in display field 4:
Pa
ge 146 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-121


Display fields

1 2 3 4
Display group 034: Oxygen sensor aging before catalytic converter (bank 1)
Display xxxx/RPM
xxx C
x.x seconds
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Period duration of oxygen
sensor before CAT Diagnostic condition
Work range 0 - 6800/RPM
70 - 850 C
0.0 - 3.0 Seconds
Test OFF
Test ON
B1-S1 OK
B1-S1 not OK
Specified
value 1900 -
2200/RPM Greater than 260
C 0.1 - 1.0 Seconds
B1-S1 OK
Note



If "B1-S1 not OK" is displayed: Check
DTC memory Page 01
-15
.
If specified value of "B1-S1 OK" is reached:

- Press -C- button.

Test requirements

Engine running at 1900 - 2200 RPM
Pa
ge 147 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-122


Display fields

1 2 3 4
Display group 035: Oxygen sensor aging before catalytic converter (Bank 2)
Display xxxx/RPM
xxx C
x.x seconds
Test ON
Indicated Engine speed
(RPM) Exhaust
temperature Period duration of
oxygen sensor
before TWC Diagnostic condition
Work range 0 - 6800/RPM
70 - 850 C
0.0 - 3.0 Seconds
Test OFF
Test ON
B2-S1 OK
B2-S1 not OK
Specified
value 1900 -
2200/RPM greater than 260
C 0.1 - 1.0 Seconds
B2-S1 OK
Note



IF "B2-S1 not OK" is displayed: Check DTC
memory Page 01
-15
.
If specified value of "B2-S1 OK" is reached:

- Press -C- button.
Pa
ge 149 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-128

Work step 11: Diagnosis of oxygen sensor
aging behind catalytic converter

Test requirements

Engine running at 1900 - 2200 RPM
System in Basic Settin
g
Q
Input display group number XXX

Indicated on display
- Press buttons -0-, -4- and -3- to select "display group number 043" and
confirm input with -Q- button.
System in Basic Setting 43
1
2
3
4

Indicated on display
- Check specified value in display field 4.
Pa
ge 156 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-131

Work step 12: Diagnosis of catalytic
converter

Test requirements

Engine running at 1900 - 2200 RPM
System in Basic Settin
g
Q
Input display group number XXX

Indicated on display
- Press buttons -0-, -4- and -6- to select "display group number 046" and
confirm input with -Q- button.
System in Basic Setting 46
1
2
3
4

Indicated on display
Note:
The test duration for catalytic converter diagnosis takes approx.: 60
seconds. - Check specified value in display field 4.
Pa
ge 160 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1

01-132


Display fields

1 2 3 4
Display group 046: Diagnostic of catalytic converter (Bank 1)
Display xxxx/RPM
xxx C
x.x s
---
Indicated Engine speed
(RPM) Catalyst
temperature Catalytic
converter
conversion Diagnostic condition
Work
range 0 - 6800/RPM
70 - 850 C
0.0 - 0.99
Test OFF
Test ON
Cat B1 OK
Cat B1 not OK
Specified
value 1900 -
2200/RPM greater than
350 C 0.0 - 0.80
Cat B1 OK
Note



If "Cat B1 not OK" is displayed: Check DTC
memory Page 01
-15
. If no malfunction is stored
replace catalytic converter.
If the specified value "Cat B1 OK" is reached:

- Press -C- button

Engine running at 1900 - 2200 RPM
Pa
ge 161 of 166 Motronic s
ystem, On Board Dia
gnostic
(OBD
)
11/22/2002 htt
p://127.0.0.1:8080/audi/servlet/Dis
play?action=Goto&t
yp
e=re
pair&id=AUDI.B5.FU04.01.1