scareme said:
I have a 2003 with gears cold air and the SCT Tuner from Dennis
Check engine light popped on tonight, so i ran the tuner to find the code.
DTC# - 01 - P0172 -- (how serious is it?)
What P0172 is trying to tell you is that the PCM has detected a rich condition on bank 1 (passenger side on a MM),
and that in trying to lean it back out, the PCM reached the limits of what it could compensate for.
Is it serious? It depends. If it really is running rich, a long trip could damage your catalyst. If it's not really running
rich, the catalyst is probably safe, but the PCM is still leaning out the mix, which elevates combustion and exhaust
temperatures. That's not good either.
A rich condition could be caused by a faulty injector, temperature sensor, or an ignition misfire. A false rich indication
could be a bad oxygen sensor, temperature sensor, throttle position sensor, or an improperly functioning mass airflow
meter. (Usually all but the oxygen sensor will eventually cause a P0175 as well.)
This is where having a scan tool that can do real-time monitoring comes in handy.
The pinging suggests it's leaning out when it doesn't need to, but you still could have a single cylinder running
rich, and the others on that bank are getting leaned out as the system tries to compensate. Reading the plugs
might show a single cylinder running richer than the others, but even if the plugs all look normal, that doesn't
prove it's not running rich. In this age of EFI and unleaded fuel, plug reading isn't quite so easy as it used to be.
Your cold-air kit could be affecting the accuracy of the mass airflow meter. Has this been installed long?
If it were my car, I probably wouldn't want to take any long trips in it until I got this sorted out...
