Powertrain, generic · Transmission

P07B3 Transmission Park Position Sensor/Switch A Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

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. P07B3 means sensor A reads below its valid zones: GM's selector modules flag below 446 counts (43.6 % of 5 V) in 16 of 20 samples, the ICCM below 35 %, the 2025 diesel engine module at a raw value of 115 or less – all after two trips. A short to ground or an open supply is typical. Hyundai uses the wording 'circuit low' for P07B5 instead.

Likely causes

Signal shorted to ground or supply wire open
Selector knob not fully seated or connector not latched
Sensor in the P button faulty
Selector or control module

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

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 h

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

Parts involved

park position sensorelectronic range selectorsensor wiringtransmission control module

Related codes

P07B4P07B5P07B2P07B9P07BE

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.