Diagnostic Trouble Code P0420 - Saab 9000 Service Manual

Fault diagnosis 175
Diagnostic trouble code P0420 (contd.)
4
[1
3HC~
Km/h
0000
j'-""
◊
0000
0000
0000·
00c:J
4 Final check:
- Clear the diagnostic trouble code.
- Implementation of driving cycle:
• Drive the car at varying engine loads and rpm
until the temperature of the coolant reaches
60°C (140° F},
or for at least 5 minutes if this temperature is
reached earlier.
• Drive the car with a steady throttle opening at
25-56mph (40-90km/h} for 4 minutes (se-
lect a gear that will keep engine speed at
2000-3000rpm}.
• Since throttle position changes should be av-
oided, as level a road as possible should be
chosen.
- Evaluation of the driving cycle:
- Connect an ISAT scan tool.
- Select "READ ON/OFF".
- Select "DIAGNOSTIC STATUS".
- Select "CATALYTIC CONVERTER".
Does the ISAT scan. tool show "NOT READY"?
I
YESI Repeat the driving cycle.
I
NO
I
Check whether the diagnostic trouble code .
has recurred. Has it recurred?
2000-3000RPM
Pxxxx?
I
YESI
Proceed to page_ 282.
0000
0000
0000
0000
00c:J
I
NO
I
The remedial measure taken was correct.
Saab9000
I