Having disconnected the battery while replacing fuses or having replaced a fuse(s) which belongs to your BMW's emission control computer would have caused the Emission Monitors (also known as Readiness Flags) to erase. The Generic OBD II Drive Cycle below will usually set the necessary emission monitors. This OBDII drive cycle begins with a cold start (coolant temperature below 122 degrees F). We recommend achieving this by letting your BMW cool down overnight, and beginning the drive cycle process the next day. Take extra caution while performing drive cycles on public roadways. Drive cycles can be difficult to follow under normal driving conditions.
Begin by:
- Start the engine. Idle the engine in drive for two and a half minutes with the A/C and rear defroster on.
- Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle.
- Hold at a steady speed of 55 mph for three minutes.
- Decelerate (coast down) to 20 mph without braking or depressing the clutch.
- Accelerate back to 55 to 60 mph at ¾ throttle.
- Hold at a steady speed of 55 to 60 mph for five minutes.
- Decelerate (coast down) to a stop without braking.
If all other emissions systems are functioning properly, completing the drive cycle above will set the "readiness flags" required to pass the smog check. It will not hurt to perform the drive cycle 2 or 3 times before the smog inspection.
Having already driven 230 miles you have to believe during some point of your drive you performed the above drive cycle. We'd recommend following the drive cycle above prior to your next smog check. If your BMW still fails the smog check for not ready emission monitors you might need to have the dealership or a BMW expert smog repair station perform the drive cycle in-house using a dynamometer.
posted by SmogTips Support
