P0401 on Hyundai
Exhaust Gas Recirculation Flow Insufficient
P0401 on Hyundai vehicles indicates exhaust gas recirculation flow insufficient. Au7o has documented this code across 2 Hyundai models — most commonly on Accent, Kona. 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. Typical repair costs on Hyundai range from $110 to $1,400, depending on the specific model and root cause.
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 Hyundai by Model
Hyundai Accent(1 issue)
- Crankshaft Position Sensor Failure2012-2022
The crankshaft position sensor on the 1.6L Gamma engine in the Accent fails prematurely, causing no-start conditions, intermittent stalling, and rough running. The sensor's internal hall-effect element degrades from heat exposure near the engine block. Common failure between 60,000-100,000 miles.
Hyundai Kona(1 issue)
- IVT/CVT Judder and Droning Noise2018-2025
The Kona with the 2.0L engine uses Hyundai's IVT (Intelligent Variable Transmission, a chain-driven CVT) that can develop juddering at low speeds and a droning noise at highway speeds. The transmission fluid degrades faster than expected, and the chain and pulleys wear. TSB 21-AT-005 addresses judder concerns.
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What does P0401 mean on Hyundai?▼
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 Hyundai specifically, this code is documented across 2 models.
What causes P0401 on Hyundai vehicles?▼
Common causes on Hyundai: 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 Hyundai?▼
Repair costs on Hyundai range from $110 to $1,400, depending on the specific model and root cause.
Which Hyundai models have P0401 documented?▼
Au7o has documented P0401 on 2 Hyundai models: Accent, Kona.