P2646: owner reports and bulletins

Powertrain (generic, all makes). We haven't written the explanation for this code yet. Below is what owners and manufacturers have filed with NHTSA.

Got P2646 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

9 complaints filed with NHTSA mention P2646, 8 of them since 2015, across 4 different models. The component owners most often filed it under: power train.

Most-reported models

VehicleComplaintsModel years reported
CHEVROLET MALIBU62014, 2015

Manufacturer service bulletins that name P2646

6 technical service bulletins and manufacturer communications filed with NHTSA mention P2646, from 2 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • TOYOTA COROLLA HATCHBACK (2020, 2018, 2019), bulletin 10164873: TSB: Some 2018 - 2019 model year C-HR (equipped with a 3ZR-FAE engine) and 2020 model year Corolla (equipped with a 2ZR-FAE engine) vehicles may exhibit a MIL ON condition with one or more of the following Diagnostic Tro…
  • TOYOTA COROLLA (2014), bulletin 10111178: TSB: Some 2014 model year Corolla vehicles equipped with the 2ZR-FAE engine may exhibit a MIL "ON" condition with either one or both of the following Diagnostic Trouble Codes (DTCs): * P2646 - A Rocker Arm Actuator Syste…
  • HONDA ELEMENT (2003, 2004, 2005, 2006), bulletin 10098946: "SERVICE BULLETIN - THE MIL COMES ON WITH ONE OF THESE DTCS: P2646/P2651 (ROCKER ARM OIL PRESSURE SWITCH CIRCUIT LOW VOLTAGE). P2647/P2652 (ROCKER ARM OIL PRESSURE SWITCH CIRCUIT HIGH VOLTAGE). NOTE: THE SYMPTOM MAY BE I…

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.