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P0804 Powertrain

Upshift/Skip Shift Lamp Control Circuit

General electrical fault on the upshift/skip-shift indicator lamp control circuit — the dashboard light that prompts the driver to skip from 1st straight to 4th. With the input invalid the lamp cannot be illuminated.

Affected components

  • Skip shift lamp
  • Wiring harness

Common causes

  • High likelihood: Open or shorted lamp wire
  • Medium likelihood: Failed lamp bulb or LED

Possible symptoms

  • Check engine or transmission warning light on
  • Harsh, delayed, or missing shifts
  • Possible limp mode (locked in one gear)
  • Slipping or shuddering during gear changes

Diagnostic notes

  • The malfunction indicator lamp may illuminate

Related codes

Sources

Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.

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