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Home >> Jeep >> 2009 >> Commander Overland, 4WD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> DTCS P0125 To P0196 - NGC >> P0138-O2 Sensor 1/2 Circuit High >> Possible Causes
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Possible Causes

Possible Causes 
(K141) O2 1/2 SIGNAL CIRCUIT SHORTED TO VOLTAGE
(K904) O2 RETURN DOWNSTREAM CIRCUIT SHORTED TO VOLTAGE
(K141) O2 1/2 SENSOR SIGNAL CIRCUIT OPEN
(K904) O2 RETURN DOWNSTREAM CIRCUIT OPEN
1/2 O2 SENSOR
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. See  DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure  .