Tips: Mazda Speed 6 OBDII emissions test with mods
This week I took the speed6 to do a mandatory OBDII emissions test, so I thought I’d share the results and some tips.
Here in the province of Ontario we have what’s called the Drive Clean program. We’re allowed to have 1 “not ready” emissions monitor and still pass the test, as long as the MIL is off. The rules are similar to many American states, if not identical.
If you have certain engine mods like me, you’ve probably turned off some DTCs using Accesstuner Race to keep the MIL off. You wouldn’t pass an OBDII emissions test with the MIL on. But it’s important to make sure that the DTCs that you’ve disabled do not affect any emissions-related monitors. If an emissions monitor is affected by a DTC that you’ve turned off in your map, that monitor will never move to the “ready” state – so keep that in mind.
I have the following DTCs disabled in my map:
P0401 EGR flow insufficient detected
P0403 EGR valve (stepper motor) circuit malfunction
P2006 Variable swirl control system shutter valve stuck closed
P2009 Variable swirl solenoid valve control circuit low
The first two DTCs take care of the EGR delete. Because they are disabled, the EGR emissions monitor will never move to the “ready” state. The last two DTCs take care of the VTCS delete – they have no effect on emissions monitors. Here’s my test result (PASS – with only the EGR system not ready). Remember that I’m allowed to have 1 “not ready”.
If I had a catless exhaust (which I don’t) and I disabled the “catalytic system warm up” DTC (P0421?), I probably would not pass this test because the CATALYST monitor would never be “ready” and I would have 2 “not ready” monitors in total. If you find yourself in this situation, you should consider a hardware solution (spark plug de-fouler?) to keep the catalyst system happy, rather than disabling that DTC.
The easiest way to check if you will pass an OBDII emissions test is to buy a cheap OBDII scan tool I.E VXDIAG for Ford Mazda $ 99+ shipping that has the I/M (Inspection & Maintenance) feature, which allows you to check the readiness state of all emissions-related monitors. I paid $30 for mine on sale.
It’s also helpful to have access to our service manual, in case a certain emissions monitor unrelated to your disabled DTCs is still in the “not ready” state. This can occur if you’ve recently disconnected the battery or reset the ECU, but haven’t completed a full drive cycle yet. The service manual tells you the exact conditions and steps you need to follow to bring individual emissions systems to the “ready” state. Sure you can drive around for a while and keep scanning until “ready”, but depending on your driving style certain systems will take weeks to become “ready”. Following the service manual’s drive cycle for each system can get the job done in a day or so.
Hope this helps.