P0401 on Chevrolet
Exhaust Gas Recirculation Flow Insufficient
P0401 on Chevrolet vehicles indicates exhaust gas recirculation flow insufficient. Au7o has documented this code across 1 Chevrolet model — most commonly on Colorado. 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 Chevrolet range from $400 to $2,200, 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 Chevrolet by Model
Chevrolet Colorado(1 issue)
- 2.8L Duramax EGR Valve Carbon Clogging and EGR Cooler Weld Seepage Causing Coolant Loss2016-2022
Separate from the DEF/DPF aftertreatment faults, the 2.8L Duramax's exhaust gas recirculation hardware itself fails in two distinct ways. First, the EGR valve and intake tract pack with soot and oil-vapour carbon, particularly on short-trip trucks, giving rough idle, hesitation, poor economy and EGR flow codes. Second, owners report the EGR cooler developing a fissure at a weld that seeps coolant only under system pressure - the truck loses coolant slowly with no puddle on the ground, and the leak stops as soon as the engine cools and pressure drops, which makes it notoriously hard for a dealer to confirm. Diesel Colorado owners have chased unexplained coolant loss for months on this. Diesel-only; the gasoline Colorados do not use this hardware.
Looking for P0401 on a different make?
View P0401 across all makes →Frequently Asked Questions
What does P0401 mean on Chevrolet?▼
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 Chevrolet specifically, this code is documented across 1 model.
What causes P0401 on Chevrolet vehicles?▼
Common causes on Chevrolet: 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 Chevrolet?▼
Repair costs on Chevrolet range from $400 to $2,200, depending on the specific model and root cause.
Which Chevrolet models have P0401 documented?▼
Au7o has documented P0401 on 1 Chevrolet model: Colorado.