OBD II Fault Code B121D :

Description of Fault code B121D

Hum-Temp Sensor Communication Error

Possible failuer B121D

• Hum-Temp Sensor communication line open or short
• Hum-Temp Sensor failure
• Climate Control Unit circuit failure

Diagnostic Procedure using AutoHex II Scan Tool

• The built-in diagnostic data in the EEPROM internal conflicts.
• Reading the data from the EEPROM is abnormal.
• Writing the data from the EEPROM is abnormal.
• When the message of the EEPROM is judged as wrong, the predetermined alternative value is output.

Test Conditions using AutoHex tester

• During the access to the EEPROM

Clear Fault codes Conditions

• The built-in diagnostic data in the EEPROM internal conflicts.
• Reading the data from the EEPROM is abnormal.
• Writing the data from the EEPROM is abnormal.
• When the message of the EEPROM is judged as wrong, the predetermined alternative value is output.

MIL Status

• Check Engine Light ON

Note:

• AutoHex II is a professional Auto diagnostic.
• This fault code is a GERENRIC fault code, some cars may change the meaning of this fault code.
  To get the accurate fault code description you may use AutoHex II

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