C0273 Diagnostic Trouble Code

C0273 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a C0273 diagnostic trouble code may include:

Rich or lean exhaust
Fuel pressure too low
Engine surge
Reduction in engine performance, especially at low RPM levels

Possible Causes :

A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
Some aftermarket accessories and performance modifications
Faulty IMRC actuator relay (if equipped)

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. 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. 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 C0273 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 C0273.

Fortunately, C0273 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0273 Trouble Code For Specific Cars

C0273 Maserati Auge Transmission Fluid Pressure Sensor/Switch B Circuit Low
C0273 Alfa Romeo 33 Accelerator Position Sensor Out of Range
C0273 Opel Grandland X Dim Panel Increase Input Circuit Open
C0273 Honda N600 RCNT Solenoid Circuit Malfunction
C0273 Mg Pb Air Suspension Warning Lamp Circuit Short To Ground
C0273 Fso Polonez O2 Sensor Circuit High Voltage (Bank 1 Sensor 3)
C0273 Skoda Yeti Lack Of HO2S22 Switch - Sensor Indicates Rich