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P2538 Powertrain

Ignition Switch Accessory Position Circuit High

The ACC input reads stuck high — short to battery voltage. The ECM cannot detect when the operator releases the switch from ACC, accessory power timeouts do not work.

Affected components

  • Ignition switch
  • Wiring harness

Common causes

  • High likelihood: ACC wire shorted to battery voltage
  • Low likelihood: Connector pins corroded - high contact resistance
  • Low likelihood: Supply wire pinched against B+ source

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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