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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 419 (5.7L CNG - DTCS P2135 To U147B - 2500 Hd) >> Diagnosis And Testing >> P2271-O2 Sensor 1/2 Signal Biased Rich >> Possible Causes

Possible Causes

WARNING: This page is about a different car, the 2013 RAM 2500 HD and 2012 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Possible Causes 
OXYGEN SENSOR WIRING OR CONNECTORS
O2 SENSOR 1/2 SIGNAL CIRCUIT
O2 SENSOR 1/2 RETURN CIRCUIT
O2 SENSOR 1/2
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Refer to  STANDARD PROCEDURE  .