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P0827moderate severityPowertrain

Up and Down Shift Switch Circuit Low

on 2025 GMC Canyon AT4X 2.7L I4 Turbo · 4WD

What this code means

The signal from the manual up/down shift switch circuit is reading lower than expected. This usually points to a short to ground or open in the circuit.

Symptoms

  • Manual shift requests ignored
  • Transmission warning light on
  • Intermittent shift response

Common causes

  • Short to ground in switch circuit
  • Faulty up/down shift switch
  • Corroded or damaged connector
  • Faulty transmission control module

Diagnostic steps

  1. Retrieve codes and freeze frame data
  2. Measure signal voltage at the switch
  3. Check wiring for shorts to ground
  4. Repair circuit or replace switch as needed

Other Powertrain codes on this vehicle

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