Powertrain, generic · Transmission

P08A1 Gear Lever Y Position Sensor 2 Circuit Low

Check engine lightOn
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

The selector lever's Y-axis sensor 2 is one of two redundant Hall sensors that send the lever travel as a PWM duty cycle. GM documents P08A1 for its electronic range selection: the code sets when the measured duty cycle of Y sensor 2 drops below 17 % (2019 ECM and ICCM tables) or below 5 % (Cadillac XT4 2019, ECM tables 2023–2025), checked 3 of 4 samples at 25 ms or 10 of 12 in later years. Typical reasons are a signal wire shorted to ground, a missing sensor supply or a dead sensor output. Type B, MIL after two trips. Unlike P08A0 this is a pure signal limit, not a plausibility check; high is P08A2. Sensor 1 keeps the selector working.

Likely causes

Sensor 2 signal wire shorted to ground
Sensor supply open or connector backed out
Sensor 2 in the selector assembly without output
Connector corrosion from liquid in the console

Symptoms

  • Check engine light after two drives
  • Shifter warning message in the cluster
  • Normally no change in driving, sensor 1 takes over

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time0.5–2 h

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

Parts involved

gear lever y position sensor 2wiring harnesstcm

Related codes

P08A0P08A2P08A3P082EP089C

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