Powertrain, generic · Transmission

P081A Starter Disable Circuit Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

The starter disable line carries the signal 'park or neutral – start allowed' from the transmission module, or its built-in range switch, to the body or engine module, which only then releases the starter. On Saab's 2010 9-5 automatic the line is open in a drive range (0 V at the body module) and closed in P or N (12 V). P081A means the start release line is too low – the output is shorted to ground or open. Saab's 2012 9-3 transmission module checks it in D, where the output must have a defined state, with 9–18 V, not in limp mode and continuously; no time threshold is published. Because the engine module then sees no 'P/N', the engine may not start.

Likely causes

P/N line to the engine module shorted to ground
Line or connector open
Connector oxidized or pins pushed back
Transmission module output stage faulty

Symptoms

  • Engine does not start or only sometimes
  • Starter does not crank in P or N
  • No check engine lamp

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,200
Time1–3 h

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

Parts involved

starter disable circuittransmission control modulebody control module

Related codes

P0817P081BP081CP0850P0616

References: saabwisonline.com, saabwisonline.com, law.cornell.edu.