Powertrain, generic · Transmission

P09A6 Gate Select Position Circuit C

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Electrical fault on a third gate select position signal (circuit C) that fits none of the more specific C codes. Public AMT designs show far fewer channels: Aisin AI and Isuzu use one select sensor, and a Mannesmann Sachs patent combines motor encoders with an extra neutral position sensor. What a third channel is in practice remains open. No manufacturer documents this code publicly. CARB requires circuit checks on such inputs. P09A7 to P09A9 are the plausibility, low and high faults of C; as with circuit B there is no intermittent variant. P0904 and P09A2 cover circuits A and B. Gear changes may be limited.

Likely causes

Loose, corroded or wet connector at the select sensor or actuator unit
Damaged signal wire of circuit C in the gearbox harness
Faulty sensor supplying signal C
Faulty input stage for circuit C in the transmission control module

Symptoms

  • Check engine or transmission warning light on
  • Delayed or missing gear changes
  • Vehicle reluctant to pull away

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,500
Time0.5–4 h

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

Parts involved

gate select position sensor cwiring harnesstcm

Related codes

P09A7P09A8P09A9P0904P09A2P0909

References: law.cornell.edu, patents.google.com, patents.google.com.