EV Diagnostics
Source-backed diagnostic reference

P1621 EV diagnostic code

PCM Memory Performance

Reference status: This page preserves source-backed code definitions for discovery. Manufacturer/model applicability, repair steps and safety conclusions are not treated as verified unless a manufacturer-specific verified report is available.

Reference definitions

  • BUICK: PCM Memory Performance Source
  • CADILLAC: PCM Memory Performance Source
  • CHEVY: PCM Memory Performance Source
  • GM: PCM Memory Performance Source
  • GMC: PCM Memory Performance Source
  • MAZDA: Immobilizer System Fault Source
  • OLDSMOBILE: PCM Memory Performance Source
  • OTHER: Control Module Long Term Memory Performance/ Immobilizer Code Words Do Not Match Source
  • SATURN: PCM Memory Performance Source
  • VOLKSWAGEN: Engine Coolant Temperature Signal Short To Ground Source

Search and canonical URL

Capitalization, underscores, hyphens, colons and spaces are normalized to this canonical code identity so alternate scan-tool formats do not create duplicate pages.