Home >> Volvo >> 2004 >> V40 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control Module (ECM) Diagnostic Trouble Codes - 1 Of 3 >> ECM-1A: Rear Heated Oxygen Sensor (Ho2S) Signal. Signal Missing. Permanent Fault (B4204T2 CVVT; 2000) >> Signal missing. Permanent fault >> Replacing the component