C0278 Arista Passy Diagnostic Trouble Code

C0278 Arista Passy code definition:
C0278 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Arista Passy.

C0278 Arista Passy is described as Fuel System Too Rich, which basically means bank 1's oxygen sensor has detected a rich condition of fuel. This means there's not enough oxygen in the exhaust from too much fuel being delivered into the air and gas mixture for combusion. There are two wires dedicated for each coil; one is battery feed which usually comes from the distribution center, and the other one for the coil driver circuit from the PCM. The PCM grounds or ungrounds the circuit to activate or deactivate the coil.

Symptoms

Symptoms of a C0278 Arista Passy diagnostic trouble code may include:
  • Engine surge
  • Blown fuse (if applicable)
  • Lack of power
  • If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected
Place of C0278 in engine

Possible Causes :

  • A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
  • Faulty IMRC actuator relay (if equipped)
  • Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Common Misdiagnoses

  1. IC Circuit High Voltage Problem
  2. Control Module Throttle Actuator Position Performance Problem
  3. Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
  4. Cruise Vehicle Speed/Set Speed Difference Too High Problem
  5. PCM Stack Overrun Problem

Repair Processes :

If you find a related TSB, the information will often help in diagnosing the code in question as TSBs are crested from many thousands of repairs. Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed.

Process Tips

Diagnostic trouble code C0278 Arista Passy 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 C0278 Arista Passy.

Fortunately, C0278 Arista Passy is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

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