P0401 on Nissan vehicles Not enough exhaust gas is being recirculated

A model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.

Owners’ own words, scrubbed of anything identifying. Unverified reports filed with NHTSA — what was said, not a finding that it was true.

Bulletins and campaigns Nissan filed with NHTSA whose summary names P0401. Quote the document number at the service desk — it is a diagnosis the maker has already written down.

• NTB22-067 Service bulletin
  2022-07-29 · Engine And Engine Cooling
• MIL ON WITH DTC P0401 AND/OR P0404 STORED IN THE ECM IF YOU CONFIRM The MIL is ON and DTC P0401 (EGR A FLOW INSUFFICIENT) and/or P0404 (EGR A CONTROL) is stored in the ECM. AND There are no drivability concerns. ACTION 1. Confirm the current ECM part number. 2. Reprogram the ECM, if applicable.
• NTB22-067A Service bulletin
  2022-10-14 · Engine And Engine Cooling
• MIL ON WITH DTC P0401 AND/OR P0404 STORED IN THE ECM This bulletin has been amended. See AMENDMENT HISTORY on the last page. Please discard previous versions of this bulletin.
• NTB23-015 Service bulletin
  2023-02-23 · Engine And Engine Cooling
• MIL ON AND DTC P0401 STORED IN THE ECM IF YOU CONFIRM The Malfunction Indicator Lamp (MIL) is ON and DTC P0401 (EGR System) is stored in the ECM. ACTION 1. Inspect the EGR fitting on the intake air duct (Figure 1) for a restriction. 2. Replace the intake air duct if a restriction is present in the EGR fitting.

A stored code names the test that failed, never the part that caused it. The record above is what Nissan and its owners have filed about it; the code’s page across every make has the whole file.