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Home >> Dodge and Ram >> 2024 >> ProMaster 2500 Base >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> 3.6L - DTCS P0125 To P0140 >> DTC Troubleshooting >> P0139 O2 Sensor 1/2 Slow Response >> Possible Causes
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Possible Causes

Possible Causes
RESTRICTED INTAKE AIR FLOW (PLUGGED AIR FILTER)
LEAK IN THE EXHAUST SYSTEM
UPSTREAM AND DOWNSTREAM O2 SENSOR HARNESS CONNECTORS SWITCHED
O2 SENSOR 1/2 INSTALLED INCORRECTLY
O2 SENSOR 1/2
ENGINE MECHANICAL ISSUE CAUSING O2 SENSOR CONTAMINATION
POWERTRAIN CONTROL MODULE (PCM)

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. Refer to  PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE  .