P0156: 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 P0156 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

No consumer complaints filed with NHTSA mention P0156. That usually means it's rare, or owners don't quote the code when they file.

Manufacturer service bulletins that name P0156

4 technical service bulletins and manufacturer communications filed with NHTSA mention P0156, from 2 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • JAGUAR F-TYPE (2015, 2016), bulletin 10097084: "ISSUE: THE CUSTOMER MAY OBSERVE A MIL IN THE INSTRUMENT CLUSTER RELATING TO THE ENGINE SYSTEM (CHECK ENGINE LIGHT) AND ONE OR MORE CODES STORED IN THE PCM RELATING TO HEATED OXYGEN SENSOR (HO2S) IN THE EXHAUST SYSTEM. T…
  • LAND ROVER RANGE ROVER (2016), bulletin 10105881: "ISSUE: THE CUSTOMER MAY OBSERVE A MIL IN THE INSTRUMENT CLUSTER RELATING TO THE ENGINE SYSTEM (CHECK ENGINE LIGHT) AND ONE OR MORE CODES STORED IN THE PCM RELATING TO HEATED OXYGEN SENSOR (HO2S) IN THE EXHAUST SYSTEM. T…
  • JAGUAR XF (2013, 2014, 2015), bulletin 10096822: "SITUATION: THE ENGINE MALFUNCTION INDICATOR LAMP (MIL) MAY BE ILLUMINATED. UPON DIAGNOSIS, THE TECHNICIAN MAY FIND DIAGNOSTIC TROUBLE CODES (DTC) RELEVANT TO THE MID-CATALYST AND POST-CATALYST HEATED OXYGEN SENSORS (HO2…

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.