LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1990 >> Forward Control 3.9 L >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - TBI >> Diagnostic Tests >> Code 45: Rich Exhaust Indication >> EGR Problem
April 5, 2026: LEMON Manuals is launched! Read the announcement.

EGR Problem

EGR valve sticking open at idle is usually accompanied by a rough idle and/or stalling. If Code 45 is intermittent, see INTERMITTENTS in H - TESTING W/O CODES article.

Fig 1: Code 45: Flow Chart Rich Exhaust Indication
G120824
scientia non olet · About LEMON Manuals