2018 Subaru WRX BaseFACTORY OEM SERVICE PROCEDURE

Tire Pressure Monitor System (TPMS) DTCS

TIRE PRESSURE MONITOR SYSTEM DIAGNOSTIC TROUBLE CODE IDENTIFICATION

DTC Item Remarks
C2021 TIRE 1 AIR PRESSURE LOW (NORMAL MODE) Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2021 TIRE 1 AIR PRESSURE LOW (NORMAL MODE) .
C2022 TIRE 2 AIR PRESSURE LOW (NORMAL MODE) Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2022 TIRE 2 AIR PRESSURE LOW (NORMAL MODE) .
C2023 TIRE 3 AIR PRESSURE LOW (NORMAL MODE) Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2023 TIRE 3 AIR PRESSURE LOW (NORMAL MODE) .
C2024 TIRE 4 AIR PRESSURE LOW (NORMAL MODE) Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2024 TIRE 4 AIR PRESSURE LOW (NORMAL MODE) .
C2121 TRANSMITTER 1 NO DATA Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2121 TRANSMITTER 1 NO DATA .
C2122 TRANSMITTER 2 NO DATA Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2122 TRANSMITTER 2 NO DATA .
C2123 TRANSMITTER 3 NO DATA Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2123 TRANSMITTER 3 NO DATA .
C2124 TRANSMITTER 4 NO DATA Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2124 TRANSMITTER 4 NO DATA .
C2221 TRANSMITTER 1 PRESSURE DATA ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2221 TRANSMITTER 1 PRESSURE DATA ABNORMAL .
C2222 TRANSMITTER 2 PRESSURE DATA ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2222 TRANSMITTER 2 PRESSURE DATA ABNORMAL .
C2223 TRANSMITTER 3 PRESSURE DATA ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2223 TRANSMITTER 3 PRESSURE DATA ABNORMAL .
C2224 TRANSMITTER 4 PRESSURE DATA ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2224 TRANSMITTER 4 PRESSURE DATA ABNORMAL .
C2321 TRANSMITTER 1 FUNCTION CODE ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2321 TRANSMITTER 1 FUNCTION CODE ABNORMAL .
C2322 TRANSMITTER 2 FUNCTION CODE ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2322 TRANSMITTER 2 FUNCTION CODE ABNORMAL .
C2323 TRANSMITTER 3 FUNCTION CODE ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2323 TRANSMITTER 3 FUNCTION CODE ABNORMAL .
C2324 TRANSMITTER 4 FUNCTION CODE ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2324 TRANSMITTER 4 FUNCTION CODE ABNORMAL .
C2421 TRANSMITTER 1 BATTERY VOLTAGE LOW Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2421 TRANSMITTER 1 BATTERY VOLTAGE LOW .
C2422 TRANSMITTER 2 BATTERY VOLTAGE LOW Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2422 TRANSMITTER 2 BATTERY VOLTAGE LOW .
C2423 TRANSMITTER 3 BATTERY VOLTAGE DECREASE Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2423 TRANSMITTER 3 BATTERY VOLTAGE DECREASE .
C2424 TRANSMITTER 4 BATTERY VOLTAGE LOW Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2424 TRANSMITTER 4 BATTERY VOLTAGE LOW .
C2521 SPEED ABNORMAL Ref. to TIRE PRESSURE MONITORING SYSTEM (DIAGNOSTICS)>Diagnostic Procedure with Diagnostic Trouble Code (DTC)>DTC C2521 SPEED ABNORMAL .
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.