CEL Code P0171 followed by 0174 and 481 on 2001 MPV
 

Hello, I had a lot of problems with CEL when I first bought this van new in 2001. I had it in at least 4 times in the first year, and each time they said it was nothing serious, but it would come back on a week later. After the 4th time, it stayed off for 5 years. The best they could say was that something had just came down from Mazda on it, and it appears to be "bad gas" from some stations such as Hucks or Citgo....that I should go to a "better" gas station, such as Shell, Phillips66, or Mobil.

About 4 months ago it came on, and I took it to a local repair shop, and they charged me $75 to pull the code and look it over for 30 minutes. This time, they said it checked out as a cooling fan issue and possibly the catalytic converter...however, the fans were all operable he said, and the converter checked out ok. So, he said to "keep an eye on it"

Well, about 3 weeks ago, CEL's back on, and I decided to take it today to Autozone this time and try to understand for myself what is going on with my vehicle.

I now have 3 codes:

P0171 "System too lean - bank 1"
P0174 "System too lean - bank 2"
P0481 "Cooling fan 2 - control circuit"

Also, I notice it has started idling pretty rough/choppy the past 3-4 days.

Any ideas would be appreciated !!

Thanks

RE: CEL Code P0171 followed by 0174 and 481 on 2001 MPV
 

The lean codes mean the engine is not getting enough fuel. Since both banks are lean i would suspect the fuel filter and or injectors are dirty. I would replace the fuel filter and run a can of Techron or Seafoam in the gas tank to clean the injectors and decarbon the valves.
For the fan circuit code i would suspect a fan motor drawing excessive amperage due to worn brush. The relay on that fan circuit has most likely suffered for it so you are most likely looking at at least one motor and 1 relay though there are 2 relays in that circuit. Test the amperage draw of the fans. Amperage draw is basicly one third of the fuse rating,so if it has a 30 amp fuse the fans normal draw would be 8-10 amps or so. I would worry a bit about the fan code because if it fails, you could damage the engine due to overheating.

RE: CEL Code P0171 followed by 0174 and 481 on 2001 MPV
 

Thank you for the quick reply!! On the fuel system issue, I see from some other articles that my particular model/year is also known to have issues with the vacuum seal for air intake gasket. Is there a way to diagnose a fuel filter/injector issue from a bad air intake gasket?

Thanks again !

RE: CEL Code P0171 followed by 0174 and 481 on 2001 MPV
 

I have'nt seen many leak vacuum. The EGR ports clog and set a misfire code. You can spray a flamable carb spray around the intake to check for leaks while it is idling. If it sucks it into a leak it changes the idle.