P0645: 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 P0645 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

1 complaints filed with NHTSA mention P0645, across 1 different models. The component owners most often filed it under: electrical system:wiring.

Manufacturer service bulletins that name P0645

15 technical service bulletins and manufacturer communications filed with NHTSA mention P0645, from 4 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • FORD EXPLORER (2020, 2021, 2022, 2023), bulletin 10232481: Some 2020-2023 Explorer/Aviator vehicles may exhibit the A/C blowing warm air with DTCs P0645, P2CFC, and/or P2CFD present in the heating ventilation and air conditioning (HVAC) module. This may be due to spread terminal…
  • LINCOLN AVIATOR (2020, 2021, 2022, 2023), bulletin 10232481: Some 2020-2023 Explorer/Aviator vehicles may exhibit the A/C blowing warm air with DTCs P0645, P2CFC, and/or P2CFD present in the heating ventilation and air conditioning (HVAC) module. This may be due to spread terminal…
  • FORD ESCAPE (2017, 2018, 2019), bulletin 10176943: Some 2017-2019 Escape vehicles equipped with a 1.5L or 2.0L engine may exhibit fuse F34 open with an illuminated MIL and diagnostic trouble codes (DTCs) P0034, P023A, P0245, P0480, P0481, P0645, P06A0, P06DB, P188D, P026…
  • LINCOLN CONTINENTAL (2017), bulletin 10093867: SOME 2017 CONTINENTAL VEHICLES EQUIPPED WITH A 2.7L OR 3.0L ENGINE WITH AWD AND BUILT ON OR BEFORE 30-SEP-2016 MAY EXHIBIT AN ILLUMINATED MALFUNCTION INDICATOR LAMP (MIL), LOW OIL PRESSURE WARNING, INOPERATIVE AIR CONDIT…
  • FORD FIESTA (2011, 2012, 2013, 2014), bulletin 10078988: AIR CONDITIONING (A/C) INOPERATIVE - DIAGNOSTIC TROUBLE CODE (DTC) P0645
  • LINCOLN MKC (2015, 2016, 2012, 2013), bulletin 10078988: AIR CONDITIONING (A/C) INOPERATIVE - DIAGNOSTIC TROUBLE CODE (DTC) P0645

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.