Home >> Porsche >> 2003 >> 911 Carrera 4S, Standard >> Repair and Diagnosis >> Brakes >> Anti-Lock Brakes >> Anti-Lock Brake System (Abs) - PSM 5.3/5/7 Diagnosis - 911 CARRERA (996) >> Fault code 4226 >> PSM 5.7: Hydraulic unit faulty; PSM 5.3: ABS exhaust valve front right >> Diagnostic conditions