Powertrain, generic · Transmission

P086A Neutral Position Sensor A Circuit/Open

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

Neutral position sensor A is a position sensor, usually a three-wire Hall sensor, on the shift shaft of a manual gearbox. It tells the engine module that neutral is selected, which start-stop needs before it may switch the engine off. Analog versions need a learned neutral value (P086F). Audi uses it as sender G701 on Q3 and A3, GM on the 2019 Corvette ZR1 with its 7-speed manual, where these codes suspend the gear ratio checks. P086A is the circuit fault: the signal is missing, typically an open supply or signal wire. Audi's bulletin for the sister codes P086D/P086E found the supply wires to G701 too short and lengthened them. Start-stop stays off.

Likely causes

Wire or connector to the sensor open or chafed
Sensor faulty
Corroded connector low on the gearbox
Supply output of the control module

Symptoms

  • Start-stop not working
  • Warning about the start system
  • MIL possible depending on maker

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–350
Time0.5–2 h

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

Parts involved

neutral position sensorsensor wiringengine control modulemanual transmission

Related codes

P086BP086CP086DP086EP086FP0850

References: static.nhtsa.gov, gsi.ext.gm.com, efiautomotive.com, patents.google.com.