P0401 on Nissan
Exhaust Gas Recirculation Flow Insufficient
P0401 on Nissan vehicles indicates exhaust gas recirculation flow insufficient. Au7o has documented this code across 4 Nissan models — most commonly on 370Z, Leaf, Pathfinder. 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 Nissan range from $200 to $8,000, 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 Nissan by Model
Nissan 370Z(1 issue)
- Concentric Slave Cylinder (CSC) Failure2009-2020
The 370Z is notorious for concentric slave cylinder failures, which is integrated with the clutch release bearing inside the transmission bell housing. When it fails, the clutch cannot be disengaged. This requires transmission removal to replace, making it a costly repair.
Nissan Leaf(1 issue)
- Battery Pack Capacity Degradation2011-2023
The Nissan Leaf uses an air-cooled lithium-ion battery that degrades faster than liquid-cooled competitors. Hot climates (Arizona, Texas) accelerate degradation significantly. Early models (2011-2015) with 24 kWh packs can lose 30-40% capacity within 5-7 years. Nissan provides an 8-year/100,000-mile battery warranty covering loss below 9 bars (approximately 66% capacity) on the dashboard gauge.
Nissan Pathfinder(1 issue)
- Coolant Leak from Thermostat Housing (VQ35DE)2013-2020
The 2013-2020 Pathfinder VQ35DE engine develops coolant leaks from the thermostat housing/water outlet, typically around 60,000-100,000 miles. The plastic housing cracks or the O-ring seal degrades, causing a slow coolant leak that can lead to overheating if not addressed. This is a common issue shared with the Murano and Maxima VQ35 engines.
Nissan Sentra(1 issue)
- A/C Compressor Failure2013-2019
The A/C compressor on 2013-2019 Sentra models is known to fail prematurely, often within 60,000-80,000 miles. The compressor clutch bearings seize or the internal components disintegrate, sending metal debris throughout the A/C system. When the compressor fails internally, the entire system often needs flushing.
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View P0401 across all makes →Frequently Asked Questions
What does P0401 mean on Nissan?▼
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 Nissan specifically, this code is documented across 4 models.
What causes P0401 on Nissan vehicles?▼
Common causes on Nissan: 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 Nissan?▼
Repair costs on Nissan range from $200 to $8,000, depending on the specific model and root cause.
Which Nissan models have P0401 documented?▼
Au7o has documented P0401 on 4 Nissan models: 370Z, Leaf, Pathfinder, Sentra.