P1604: owner reports and bulletins
Got P1604 on your scanner? Tell the mechanic your year, make, model and any symptoms and you'll get the likely cause and what to check first. Ask about this code.
What owners report to NHTSA
19 complaints filed with NHTSA mention P1604, 18 of them since 2015, across 8 different models. The component owners most often filed it under: engine.
Most-reported models
| Vehicle | Complaints | Model years reported |
|---|---|---|
| TOYOTA RAV4 | 7 | 2012, 2014, 2015, 2018 |
| TOYOTA COROLLA | 3 | 2011, 2013, 2018 |
Manufacturer service bulletins that name P1604
17 technical service bulletins and manufacturer communications filed with NHTSA mention P1604, from 4 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:
- TOYOTA SEQUOIA (2009, 2010, 2011, 2012), bulletin 10170730: TSB: SUPERSESSION NOTICE The information contained in this bulletin supersedes Service Bulletin No. T-SB-0058-13. Service Bulletin No. T-SB-0058-13 is obsolete and any printed versions should be discarded. Some 2009 ? 20…
- SUBARU ASCENT (2019, 2020), bulletin 10166949: This bulletin announces availability of reprogramming files to optimize the Engine Control Module (ECM). The new files will address isolated concerns of an extended cranking (hard starting) condition. They will also addr…
- TOYOTA HIGHLANDER (2014, 2015, 2016, 2017), bulletin 10162756: TSB: Some 2014 ? 2018 model year Highlander and Highlander Hybrid vehicles may exhibit one or more of the following conditions. ? Various drivability concerns ? Low or no fuel pressure ? Diagnostic Trouble Codes (DTCs) (…
- HINO CONVENTIONAL MODELS (2013, 2014, 2015, 2016), bulletin 10117713: SB-15-048 If a 2013-2017 COE model 195h is encountered with a will not move in any gear condition and any combination of DTC's P0706, P0756, P0761, P1604, please perform the following for engineering review.
- HINO JHP2 (2013, 2014, 2015), bulletin 10117618: SB-14-006 COE Diesel and Hybrid P1604 Code Procedure. A subject vehicle may exhibit an illuminated Malfunction Indicator Lamp (MIL) on and a code P1604 stored in the Transmission Control Module.
- HINO JHD2 (2013, 2014, 2015), bulletin 10117625: SB-14-006 COE Diesel and Hybrid P1604 Code Procedure. A subject vehicle may exhibit an illuminated Malfunction Indicator Lamp (MIL) on and a code P1604 stored in the Transmission Control Module.
Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.