Powertrain, generic · Transmission

P081D Neutral Input Circuit

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P081D concerns the input 'neutral' – the N contact of the selector or range switch, on manual cars a neutral switch or sensor for start-stop. Neutral serves for starter release, idle control without load, start-stop release and enabling other diagnostics. The check would be a circuit or plausibility test against the range sensor or speed ratio. No manufacturer document available to us uses P081D; its sister P081C is documented on the Jeep Compass, and Saab's range switch shows that P and N are the two start positions. The engine may then not start in N, start-stop is disabled and idle diagnostics may be suspended.

Likely causes

Neutral contact, range switch or neutral sensor faulty or misadjusted
Selector or shift cable misadjusted
Wire or connector
Control module or software

Symptoms

  • Engine does not start in N (only in P)
  • Start-stop not working
  • Range display does not show N

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€60–450
Time0.5–2 h

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

Parts involved

neutral switchtransmission range sensorswitch wiring

Related codes

P081CP0850P0817P0705P0706

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