P0401
P0401 — EGR Flow Insufficient
3
Driver reports
3
Solved cases
3
Verified fixes
0
Wrong repairs reported
📊 Diagnostic Overview
Severity, cost and difficulty for P0401, based on data already on this page.
Severity
🟡 Medium
Diagnostic Difficulty
Easy
System
Engine
Common Causes (based on confirmed repairs)
- EGR valve completely clogged with carbon. Removed and manually cleaned with wire brush and carb cleaner. Also cleaned EGR cooler passages. P0401 resolved. Cleaned at 90000 miles — should have been done at 60000. 1 vehicle
- P0401 = EGR system not flowing enough exhaust gas. 90% of the time this is carbon buildup blocking the EGR valve or passages. Solution: Remove EGR valve and clean with carb cleaner and a small wire brush. Clean EGR passages in intake manifold. Takes 1-2 h 1 vehicle
- P0401 EGR flow insufficient: 1) Remove and inspect EGR valve — heavily carboned valves cannot close fully or open properly. 2) Clean with carb cleaner and steel wire brush. 3) Check EGR passages in intake manifold — often blocked with carbon. 4) Test EGR 1 vehicle
📐 Diagnostic Difficulty reflects how many different repairs drivers have tried for P0401 and how often those attempts turned out to be the wrong fix — it is calculated from MyCarFault's own reports, not an official manufacturer rating.
⭐ MOST VERIFIED FIX FOR P0401
EGR valve completely clogged with carbon. Removed and manually cleaned with wire brush and carb cleaner. Also cleaned EGR cooler passages. P0401 resolved. Cleaned at 90000 miles — should have been done at 60000.
Reported in 1 approved case
·
⚪ Unverified
Top Reported Fixes for P0401
Ranked by confidence score — same vehicle matches weighted higher.
Driver Reports — P0401 3 reports
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