C0273 Alfa Romeo 33 Diagnostic Trouble Code

C0273 Alfa Romeo 33 code definition:
C0273 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Alfa Romeo 33.

C0273 Alfa Romeo 33 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. As you drive and when specific conditions are slowly met, the vapors will gradually purge from the charcoal canister and will get burned within your engine.

Symptoms

Symptoms of a C0273 Alfa Romeo 33 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)

Common Misdiagnoses

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

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 Alfa Romeo 33 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 Alfa Romeo 33.

Fortunately, C0273 Alfa Romeo 33 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.