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Service bulletins for the 2012 Toyota PRIUS

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

467 on file from NHTSA, as of 2026-10-19.

About P0401 on the 2012 Toyota PRIUS: what the code means, and the bulletins and recalls about the same components.

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Only bulletins with trouble code: P0401 are shown. Show all

Bulletins, newest first
ZF3_Toyota POL162019-09-16. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE); ENGINE; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. Warranty Enhancement Program: Toyota has received reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve in some vehicles. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
T-SB-0027-162018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). TSB: Some Prius, Prius V, and Prius PHV vehciles may exhibit a rough idle or tapping noise from the HV transaxle at cold start. The Check Engine Light may also illuminate with (DTC) P0401 (Exhaust Gas Recirculation Flow Insufficient Detected). Due to excess carbon build-up at the valve assembly, the valve will stick, causing the engine RPM to fluctuate. Follow the procedures in this bulletin to address the condition.
T-SB-0027-162018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). TSB: Some Prius, Prius V and Prius PHV vehicles may exhibit a vibration due to rough idle and/or tapping noise from the HV transaxle at cold start. The Check Engine Light may also illuminate with (DTC) P0401 (Exhaust Gas Recirculation Flow Insufficient Detected). Due to excess carbon build up at the valve assembly, the valve will stick causing the engine RPM to fluctuate. Follow the procedures in this bulletin to address this condition.
ZF3_Warranty Pol2018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Warranty Policy Bulletin (POL16-04): In these vehicles, Toyota has received some reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
ZF3_Dealer Lette2018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Dealer Letter: In these vehicles, Toyota has received some reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
ZF3_Dealer Lette2018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Dealer email: In these vehicles, Toyota has received some reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
ZF3_Region Lette2018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Region Letter: In these vehicles, Toyota has received some reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
ZF3_Region Lette2018-04-23. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Region email: In these vehicles, Toyota has received some reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
T-SB-0075-132018-04-02. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM. Some 2010-2012 model year Prius vehicles equipped with a 2ZR-FXE engine may exhibit a MIL "ON" condition with Diagnostic Trouble Code P0401 (Exhaust Gas Recirculation Flow insufficient Detected) present. The Exhaust Gas Recirculation Valve has been improved to address this condition.
ZF3_Warranty Pol2017-08-14. Service bulletin. ENGINE; ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). Warranty Policy Bulletin (POL16-04): Toyota has received reports of a rough idle and/or rattle noise from the transaxle at cold start due to a sticking Exhaust Gas Recirculation (EGR) Valve in some vehicles. If this occurs, the vehicle may illuminate the check engine light and set diagnostic trouble code (DTC) P0401.
ZF3_WARRANTY POL2017-06-14. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). WARRANTY POLICY BULLETIN (POL16-04): IN THESE VEHICLES, TOYOTA HAS RECEIVED SOME REPORTS OF A ROUGH IDLE AND/OR RATTLE NOISE FROM THE TRANSAXLE AT COLD START DUE TO A STICKING EXHAUST GAS RECIRCULATION (EGR) VALVE. IF THIS OCCURS, THE VEHICLE MAY ILLUMINATE THE CHECK ENGINE LIGHT AND SET DIAGNOSTIC TROUBLE CODE (DTC) P0401.
ZF3_DEALER LETTE2017-06-14. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). DEALER LETTER: IN THESE VEHICLES, TOYOTA HAS RECEIVED SOME REPORTS OF A ROUGH IDLE AND/OR RATTLE NOISE FROM THE TRANSAXLE AT COLD START DUE TO A STICKING EXHAUST GAS RECIRCULATION (EGR) VALVE. IF THIS OCCURS, THE VEHICLE MAY ILLUMINATE THE CHECK ENGINE LIGHT AND SET DIAGNOSTIC TROUBLE CODE (DTC) P0401.
ZF3_DEALER LETTE2017-06-14. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). DEALER EMAIL: IN THESE VEHICLES, TOYOTA HAS RECEIVED SOME REPORTS OF A ROUGH IDLE AND/OR RATTLE NOISE FROM THE TRANSAXLE AT COLD START DUE TO A STICKING EXHAUST GAS RECIRCULATION (EGR) VALVE. IF THIS OCCURS, THE VEHICLE MAY ILLUMINATE THE CHECK ENGINE LIGHT AND SET DIAGNOSTIC TROUBLE CODE (DTC) P0401.
ZF3_REGION LETTE2017-06-14. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). REGION LETTER: IN THESE VEHICLES, TOYOTA HAS RECEIVED SOME REPORTS OF A ROUGH IDLE AND/OR RATTLE NOISE FROM THE TRANSAXLE AT COLD START DUE TO A STICKING EXHAUST GAS RECIRCULATION (EGR) VALVE. IF THIS OCCURS, THE VEHICLE MAY ILLUMINATE THE CHECK ENGINE LIGHT AND SET DIAGNOSTIC TROUBLE CODE (DTC) P0401.
ZF3_REGION LETTE2017-06-14. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL:GAS RECIRCULATION VALVE (EGR VALVE). REGION EMAIL: IN THESE VEHICLES, TOYOTA HAS RECEIVED SOME REPORTS OF A ROUGH IDLE AND/OR RATTLE NOISE FROM THE TRANSAXLE AT COLD START DUE TO A STICKING EXHAUST GAS RECIRCULATION (EGR) VALVE. IF THIS OCCURS, THE VEHICLE MAY ILLUMINATE THE CHECK ENGINE LIGHT AND SET DIAGNOSTIC TROUBLE CODE (DTC) P0401.
T-SB-0027-162017-04-06. Service bulletin. ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL. TSB: SOME PRIUS, PRIUS V, AND PRIUS PHV VEHCILES MAY EEXHIBVIT A ROUGH IDLE OR TAPPING NOISE FROM THE HV TRANSAXLE AT COLD START. THE CHECK ENGINE LIGHT MAY ALSO ILLUMINATE WITH (DTC) P0401 (EXHAUST GAS RECIRCULATION FLOW INSUFFICIENT DETECTED). DUE TO EXCESS CARBON BUILD-UP AT THE VALVE ASSEMBLY, THE VALVE WILL STICK, CAUSING THE ENGINE RPM TO FLUCTUATE. FOLLOW THE PROCEDURES IN THIS BULLETIN TO ADDRESS THE CONDITION.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.