what should cause a Pontiac g6 po172

Question

what can cause the fault code and what should I check

Answer 1

Hi there,

A leaking fuel injector can cause this code. It can also occur when one of the O2 sensors on that bank is running out of range. The code happens when the fuel mixture is to rich. A scan tool that can read live data is required to watch the voltages on the O2 sensors to determine if one has failed or is running out of range.