Car slows when trying to accelerate but keeps running, get code P16A7

Question

I have a 2004 BMW 330i. Car runs fine at a constant speed but once I try to accelerate, the traction light and brake warning light come on and the car slows down and almost stops but the engine keeps running. It will only run at 20-25 MPH. When I turn the engine off and restart it, all the lights go off and it runs fine for a little while and then happens again, each time whenever I try to accelerate. I get the error code P16A7 (undefined –refers me to the BMW owner’s manual) and error code P0171 (System too lean bank 1). Any suggestions?

Answer 1

Hi there,

The code P16A7 indicates an issue with the mass air flow sensor. Here is some info for you.

P16A7 BMW - Engine Control Module Self-Test Mass Air Flow Sensor Monitoring Fault

Read more: https://www.autocodes.com/p16a7_bmw.html

And here is a list of possible causes for the fuel mix being too lean. 

P0171 BMW - Mixture Control System Too Lean

Read more: https://www.autocodes.com/p0171_bmw.html