P1A21 on the 2014 Fiat 500
The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.
This code is specific to a manufacturer and is not described here. Its meaning is in the manufacturer's service information.
| 08-048-16 | 2018-06-11. Service bulletin. FLASH: Electric Vehicle Control Unit (EVCU) System Enhancements This bulletin involves updating the software in the EVCU. A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, the technician may find the following Diagnostic Trouble Code (DTC) set in the EVCU memory: · P1A21-00 - HV Battery Contactor Control Sequence Incorrect. In addition the customer may notice one of the following conditions: · When an Electric Vehicle Supply Equipment (EVSE) is plugged in approximately 17 seconds after key off, the vehicle will not charge and will not power down. This could lead to potential 12V battery drain after prolonged period of time. · When the battery temperature is below -30°C (-22°F) and above 50°C (122°F), the thermal system does not function. · When a Level 1 EVSE is plugged in, the displayed charge time estimation for Level 2 is over estimated. The following improvements/enhancements are also included in this software release: · Improved shift strategy involving shift lever position. |
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| 08-048-16 | 2016-07-14. Service bulletin. SUBJECT: FLASH: Electric Vehicle Control Unit (EVCU) System Enhancements OVERVIEW: This bulletin involves updating the software in the EVCU. SYMPTOM/CONDITION: A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, the technician may find the following Diagnostic Trouble Code (DTC) set in the EVCU memory: • P1A21-00 - HV Battery Contactor Control Sequence Incorrect. In addition the customer may notice one of the following conditions: • When an Electric Vehicle Supply Equipment (EVSE) is plugged in approximately 17 seconds after key off, the vehicle will not charge and will not power down. This could lead to potential 12V battery drain after prolonged period of time. • When the battery temperature is below -30°C (-22°F) and above 50°C (122°F), the thermal system does not function. • When a Level 1 EVSE is plugged in, the displayed charge time estimation for Level 2 is over estimated. The following improvements/enhancements are also included in this software release: • Improved shift strategy involving shift lever position. |
| 08-048-16 | 2016-07-07. Service bulletin. SUBJECT: FLASH: Electric Vehicle Control Unit (EVCU) System Enhancements OVERVIEW: This bulletin involves updating the software in the EVCU. SYMPTOM/CONDITION: A small number of customers may experience a Malfunction Indicator Lamp (MIL) illumination. Upon further investigation, the technician may find the following Diagnostic Trouble Code (DTC) set in the EVCU memory: · P1A21-00 - HV Battery Contactor Control Sequence Incorrect. In addition the customer may notice one of the following conditions: · When an Electric Vehicle Supply Equipment (EVSE) is plugged in approximately 17 seconds after key off, the vehicle will not charge and will not power down. This could lead to potential 12V battery drain after prolonged period of time. · When the battery temperature is below -30°C (-22°F) and above 50°C (122°F), the thermal system does not function. · When a Level 1 EVSE is plugged in, the displayed charge time estimation for Level 2 is over estimated. The following improvements/enhancements are also included in this software release: · Improved shift strategy involving shift lever position. |
3 on file from NHTSA, as of 2026-10-19. See them in the bulletin list. A bulletin lists model years: read the document for which vehicles it concerns.