Recently, got feedback from one American customer, saying he got an error report when using the Foxwell NT530 BMW scanner to work on his car, BMW 2000 323 ci E46. He told our customer service that he tried very hard to get it ready for DEQ, but the scanner’s screen just showed P0170 and P0173 -Fuel Trim Bank one and two. What happened? Could I get some help?
This seems like a problem that might a little bit hard for us to work out because that’s the first time our technical support engineer has met this kind of error code report. But thankfully, we still get it fixed well as always.
Solution provided as below:
I hereby informed all of the customers of this message: P0170 and P0173 are codes for the MS42 DME, so you must be working on your 323ci.
The codes don’t tell you if the problem is a rich or lean problem. You are going to have to look at your fuel trims to work that one out. Look at all 4 of the furl trims, 2 short-term and 2 long-term.
If the long-term ones are negative, then you have a rich condition and the DME is reducing the amount of fuel (negative trims).
If the long-term ones are positive, then you have a lean condition and the DME is adding fuel (positive trims).
Have a look at the trims and tell us what they are. We’ll then help you through the diagnosis and repairs.
And we’ve got your attention here: Fixing fuel trim problems is still best fixed with a Foxwell OBD2 scanner. The fuel trims are in % and make sense. The BMW software fuel trims data is confusing.
Here is the Foxwell Professional Scanners purchase link: