P07BA: Transmission Park Position Sensor/Switch B Circuit High

What does P07BA mean?

With electronic gear selection the park position sensor/switch reports the park request or position. On GM's shift-by-wire selectors (2017 LaCrosse, XT4/XT5, Bolt EV, later SUVs and pickups) it is the P button, read by two redundant analog sensors A and B with separate 'released' and 'pressed' voltage zones. P07BA is the same check as P07B4 for sensor B: above 853 counts (83.3 % of 5 V), ICCM above 70 %, after two trips. GM's bulletin for the 2017 LaCrosse, XT5 and Bolt EV lists it when the selector knob is not fully seated or the connector is not latched.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light, 'service transmission' or 'unable to shift' message
• Park cannot be selected by button, or the car will not shift out of P
• P button illumination off

Common causes

• High Signal shorted to positive or ground open
• Medium Selector knob not fully seated or connector not latched
• Medium Sensor in the P button faulty
• Low Selector or control module

Likelihood is a general estimate across vehicles; your make and model may differ.