P1643moderate severityPowertrain

Engine Speed Output Circuit

on 2017 Chevrolet Silverado 1500 5.3L V8 EcoTec3 L83 · RWD

What this code means

The PCM detected a fault in the engine speed output circuit sent to other modules. This can affect components that rely on RPM signals.

Symptoms

  • Check engine light on
  • Tachometer erratic or dead
  • Related module faults

Common causes

  • Wiring or connector fault
  • Short or open in output circuit
  • Faulty receiving module
  • Faulty PCM

Diagnostic steps

  1. Check engine speed output wiring
  2. Test signal at receiving module
  3. Inspect connectors for damage
  4. Repair circuit or replace PCM

Other Powertrain codes on this vehicle

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