What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
4Original wording in English
TOYOTA
Reported code forms P1DEF
TSB: Some 2016 ? 2019 model year Mirai vehicles may exhibit a warning message, ?FC malfunction, return vehicle to dealer for service.? This message is accompanied by Diagnostic Trouble Code (DTC) P1DEF (450 FC Stack…
TOYOTA
Reported code forms P1DEF
TSB: REVISION NOTICE September 20, 2019 Rev2: ? Applicability has been updated to include 2018 and 2019 model year Mirai vehicles. ? The Production Change Information, Parts Information, and Calibration sections have…
TOYOTA
Reported code forms P1DEF
TSB: REVISION NOTICE September 5, 2018 Rev1: ? The Parts Information section has been updated. Any previous printed versions of this bulletin should be discarded. Some 2016 ? 2017 model year Mirai vehicles may exhibit a…
TOYOTA
Reported code forms P1DEF
TSB: Some 2016 ? 2017 model year Mirai vehicles may exhibit a warning message, "FC malfunction, return vehicle to dealer for service." This message is accompanied by Diagnostic Trouble Code (DTC) P1DEF (450 FC Stack…
Check vehicle applicability
4A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.