I’m sure this is posted somewhere on the forum, but I need to get my 09 Mustang emissions checked and I’ve restored my Brenspeed tune back to stock. Anyone know many miles or start/stop cycles I need to do before it will be ready for the test?

 

Let the car sit for at least eight hours without starting the engine. Then drive at least 10 minutes on the highway. Then, drive at least 20 minutes in stop-and-go city-type traffic with at least four idle periods. Do not turn the engine off at any time during this cycle.

If the MIL light came on, then you may need to do the above three times to get the MIL light to turn off.

If you have a code reader, it may have a function that will let you know if the car is not ready for an emissions test.

 

Why do you think you need so many stop/start cycles? Just let it idle for 10 minutes and go take the test. I've disconnected my battery to reset the long term fuel trims and it relearns them much faster than you think.

 

It needs a complete "drive cycle" so that all of the emissions monitors can run. Before my last inspection it took, believe it or not, around 900 miles for all of the monitors to run successfully. If you go over 55mph the drive cycle aborts and has to start all over again with a dead cold start.

 

I don't believe it. What monitors? I've never, technically, lived in a state that required emissions testing, but I know the computer relearns the long term fuel trims very quickly.

What is not running without a complete drive cycle? Where are you getting the term drive cycle?

 

Would you believe the Owner's Guide?

 

Monitors are the self tests the ECU performs to verify specific emission systems are working, (ie: O2 sensor, secondary air injection, evap system)

Emission tests require OBDII cars (built after 1996) to have no ECU faults and the system monitors complete. They do this in theory so someone can't just clear the fault codes and test the car before the faults come back.
It is a vefification that the specific emission systems are working.

Drive cycle a sequence of driving conditions the ECU needs to see to complete these self tests.

Folks who don't live somewhere that requires emission testing don't have to worry about this crap.

 

Scan tool can tell you if it's emissions ready. They lay out a driving cycle to get it emission ready, it just took a couple days of normal driving and the monitors to came back to readiness for me.I left the Brenspeed tune in. Had to call them to turn on the 02s and passed without any issues.

 

Thanks for everyone’s help. I’d forgotten that I could read the DTCS ready status with the SCT, it’s been over 3 ½ years since I loaded the original Brenspeed software. After I reloaded the original Ford software I drove the car about 30 miles (combination freeway and in town) and about 10 start and shut off sequences and there are no DTCS codes.