BMW 1999-2005 M3 Service Manual page 1256

On-Board Diagnostics
BMW P-code
code
232 P0179
233 P0420
234 P0430
235 P1190
236 P1191
238 P0301
239 P0302
18 of 20
Fault type and Signal type and
function range
Oxygen sensor Input analog (high
pre-cat (Bank 2), is lean) (0-5V)
switch time too
slow
Catalyst efficiency Input analog
(Bank 1), below (0-5V)
threshold
Catalyst efficiency Input analog
(Bank 2), below (0-5V)
threshold
Pre-cat sensor Input analog (high
(Bank 1):trim is rich) (0-1V)
control
Pre-cat sensor Input analog (high
(Bank 2):trim is rich) (0-1V)
control
Cyl. 1 misfire DME internal
detected values logical
Cyl. 2 misfire DME internal
detected values logical
http://ebahn.bentleypublishers.com/BMW/3/E46/Repair%20Manuals/8...
Explanation
switch fault will set.
Checks amount of time
oxygen sensor takes to switch
from rich to lean and vice
versa. If it takes too long to
switch fault will set.
Compares value of pre-cat
oxygen sensor to value of
post-cat oxygen sensor to
measure oxygen storage
capability / efficiency of
catalytic converter. Post-cat
oxygen sensor must be
relatively lean.
Compares value of pre-cat
oxygen sensor to value of
post-cat oxygen sensor to
measure oxygen storage
capability / efficiency of
catalytic converter. Post-cat
oxygen sensor must be
relatively lean.
Rationality check for O2
control adaptation with
pre-cat sensor bank 1
Rationality check for O2
control adaptation with
pre-cat sensor bank 2
Crankshaft
speed/acceleration is
monitored by crank sensor.
Time for each cylinder
combustion is compared
against avg. of others. If time
for cylinder 1 is longer, fault
will set.
Crankshaft
speed/acceleration is
monitored by crank sensor.
Time for each cylinder
combustion is compared
against avg. of others. If time
2/25/2009 11:23 PM