A rough idle, low power and an illuminated Malfunction Indicator Lamp (MIL) may be found on some 2016-2017 Acadia, Enclave and Traverse models. Several DTCs also may be set for the bank 1 oxygen (O2) sensor.
If these conditions are present, check for a power steering leak from the power steering hose above the wiring harness for the bank 1 oxygen sensor. (Fig. 9) The leak may be contaminating the O2 sensor wiring and impacting O2 sensor performance. In some cases, this may be a repeat concern.
To correct this condition, inspect the power steering inlet hose for any sign of leakage. If power steering fluid is found leaking onto the hose going into the O2 sensor wiring harness, it will be necessary to replace the bank 1 oxygen sensor and the engine wiring harness due to fluid contamination as well as the power steering gear inlet pipe/hose to stop the leak.
If no leak is found at the hose, proceed with the diagnostics outlined in the appropriate Service Information.
– Thanks to Joseph Morehead