P0401 on Lincoln
Exhaust Gas Recirculation Flow Insufficient
P0401 on Lincoln vehicles indicates exhaust gas recirculation flow insufficient. Au7o has documented this code across 1 Lincoln model — most commonly on Nautilus. This code means the Exhaust Gas Recirculation (EGR) system is not flowing enough exhaust back into the engine. The EGR system recirculates a small amount of exhaust into the intake to lower combustion temperatures and reduce nitrogen oxide (NOx) emissions; the computer has determined the actual flow is below what it commanded. The most common reason is carbon buildup clogging the EGR valve or its passages. You may notice pinging/knocking, rough idle, or a check engine light, and the car will fail emissions testing.
Common Causes of P0401
- •Carbon buildup clogging the EGR valve or passages
- •Stuck or faulty EGR valve
- •Blocked or restricted EGR ports/tubes
- •Faulty EGR temperature or position sensor
- •Faulty DPFE/EGR pressure sensor (on applicable systems)
- •Vacuum leak or failed vacuum control (vacuum-operated EGR)
- •Wiring or connector problems at the EGR valve
P0401 on Lincoln by Model
Lincoln Nautilus(1 issue)
- EGR Valve Failure Leading to Unexpected Loss of Drive Power (Recall 26S10 / NHTSA 26V122000)2025
Certain 2025 Lincoln Nautilus vehicles are part of Ford Motor Company's 26S10 recall. The exhaust gas recirculation (EGR) valve may fail, and the outcome NHTSA describes is an unexpected loss of drive power. Because the power loss can occur without warning, NHTSA cites an increased risk of a crash. The Nautilus is one of several 2025 Ford and Lincoln models in this single campaign, which totals 47,804 vehicles across all of them combined.
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View P0401 across all makes →Frequently Asked Questions
What does P0401 mean on Lincoln?▼
P0401 stands for "Exhaust Gas Recirculation Flow Insufficient." This code means the Exhaust Gas Recirculation (EGR) system is not flowing enough exhaust back into the engine. The EGR system recirculates a small amount of exhaust into the intake to lower combustion temperatures and reduce nitrogen oxide (NOx) emissions; the computer has determined the actual flow is below what it commanded. The most common reason is carbon buildup clogging the EGR valve or its passages. You may notice pinging/knocking, rough idle, or a check engine light, and the car will fail emissions testing. On Lincoln specifically, this code is documented across 1 model.
What causes P0401 on Lincoln vehicles?▼
Common causes on Lincoln: Carbon buildup clogging the EGR valve or passages, Stuck or faulty EGR valve, Blocked or restricted EGR ports/tubes, Faulty EGR temperature or position sensor, Faulty DPFE/EGR pressure sensor (on applicable systems). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0401 on a Lincoln?▼
Repair costs vary widely depending on the root cause and specific Lincoln model.
Which Lincoln models have P0401 documented?▼
Au7o has documented P0401 on 1 Lincoln model: Nautilus.