Second question first... ANY trouble code manufacturer specific or not will
cause your BMW to fail the smog test. First question... if you reset the
computer with a scan tool you will erase not only the trouble codes but the
readiness flags as well. The smog machine will see that the required
readiness flags are not set and will fail the smog inspection. At least 4
readiness flags are required to pass the smog test, one of which has to be
the fuel control (oxygen sensor and MAF mass Air Flow Sensor) readiness
flag. This is the same readiness flag which will not set if there is a fuel
control or air/fuel mixture problem. Trouble codes P1188 and P1189 are fuel
control related. P1188 relates to banks 1 (this is the side which cylinder 1
is located on) having a fuel control problem and P1189 relates to bank 2
(the side opposing bank 1) having a fuel control problem. Trouble codes
P1188 and P1189 can indicate a problem with any one of the emissions
components responsible for fuel control, i.e. Mass Air Flow Sensor, Oxygen
Sensor, Fuel Pressure regulator. Any one of these components can trigger a
P1188 or P1189. The component/s might not be completely failing, but
defective enough to cause a P1188 and P1189. I mention this only because if
any of these components were completely defective they would probably
trigger a trouble code relating to the specific component. I'm afraid you'll
need to diagnose the entire fuel control system to find out which one of
these components is causing the P1188 and P1189 before your vehicle will
pass the smog test.
posted by SmogTips Support
