Help with OBD 2 Fault Codes
 

Need help using OBD2 fault codes to diagnose misfire problem on my 1999 328i (E46). I just purchased the scan tool software from Autoenginuity.

Fault codes are as follows:

P0300: Random/multiple cylinder misfire
P0203 Injector Circuit Cylinder 3
P1900 unknown code

What does P0203 indicate? Also my O2 sensor readings appear faulty, sensor 1 for both banks is very low (.005 to .025) and does not change as I understand it should.

Also anybody know what P1900 means?

My plan is to try replacing 02 sensors and cleaning injectors with infector cleaner. Any other suggestions???

thanks for your help. you may email me at c_cline@bellsouth.net if you prefer.

Diagnosing these problems is beyond my skill level, but I would start with the simple things.

Replace sparkplugs and inspect the old ones for problems. You can learn a lot from a sparkplug. Get Bosch or NGK 4-ground plugs with either copper or platinum core.

Replace the fuel filter and run a good quality injector cleaner like Techron or even Beymans B-12.

Buy some name brand high octane gas from a fairly new station and drive the car for a few days then clear the codes and see which codes reappear.

O2 sensors are expensive an I suspect that your bad O2 readings are just a symptom.

I assume the car is running adequately.

Jeron

How do you like the Autoenginuity software? Did you do any research before you bought? Why did you pick Autoenginuity over other brands? How much and where did you get it?

Jeron

I am pleased with the Autoenginuity software I bought. Had communication problems with my PC the first time I tried to use it, but their tech support was friendly and worked thru the problem (needed to set up COM port to correct baud rate).

Software appears to have good fuctionality. I havent played with it much, but you can graph and data log data etc. However, interpreting the data is up to the user.

I did some online research, but apart from dedicated scanners, only uncovered one other (cant recall name), but their website was awful (poor documentation).

Check out autoenginuity.com as well as a review on pelicanparts website.