U279A Chrysler Sim4 Diagnostic Trouble Code

U279A Chrysler Sim4 code definition:
U279A is a kind of OBD-II Diagnostic U-Network Diagnostic Trouble Code for Chrysler Sim4.

U279A Chrysler Sim4 is described as Oxygen Sensor Circuit No Activity Detected (Bank 1, Sensor 1). This means there's a problem in the front oxygen sensor on Bank 1, as the O2 sensor is inactive. Other serious codes may cause this code to pop up, and they may come with dangerous drivability issues that may expose you to safety risks and cause damage to the engine in the long run.

Symptoms

Symptoms of a U279A Chrysler Sim4 diagnostic trouble code may include:

Fuel pressure too high
Diminished fuel efficiency
Rich or lean exhaust
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Faulty IMRC actuator relay (if equipped)

Common Misdiagnoses

Exhaust Gas Recirculation System Valve 1 Problem
BBV Sensor Circuit Low Voltage Problem
Transmission Engaged At High Throttle Angle Problem
Cruise Inhibit Control Circuit Problem
TFP Valve Position Switch-Drive Without Drive Ratio Problem

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code U279A Chrysler Sim4 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before U279A Chrysler Sim4.

Fortunately, U279A Chrysler Sim4 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.