P07B7 Transmission Park Position Sensor/Switch A Circuit Intermittent/Erratic

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. P07B7 means sensor A's signal jumps or drops out intermittently. No manufacturer document available to us uses this code; GM covers intermittent P button problems as zone or correlation faults (P07B5, P07BE); its bulletins note that off-centre pressing or a hand resting on the button can be enough. A loose contact is the likely cause.

Likely causes

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

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, static.nhtsa.gov.