LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Cadillac >> 1998 >> Eldorado Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes >> Diagnostic Trouble Codes >> DTC P1621 - Pcm Memory Performance >> Diagnostic Procedures
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedures

  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.
  2. Turn ignition on. Using scan tool, select DTC INFO and select FAIL THIS IGN. If DTC failed this ignition cycle, go to step 4). If DTC did not fail in this ignition cycle, go to next step.
  3. Clear DTC P1621. Cycle ignition on and off several times slowly. Turn ignition on for 10 seconds, then turn ignition off for 30 seconds. Using scan tool, view DTC INFO and select TEST FAIL SCC. If this DTC failed since DTCs were cleared, go to next step. If no, fault is not present.
  4. Replace PCM. Program replacement PCM using required equipment.
scientia non olet · About LEMON Manuals