1 If a fault appears in the fuel injection/engine management system of Fiat Punto, first ensure that all the system wiring connectors are securely connected and free of corrosion. Ensure that the fault is not due to poor maintenance; i.e. check that the air cleaner filter element is clean, the spark plugs are in good condition and correctly gapped, the valve clearances are correctly adjusted (where applicable), the cylinder compression pressures are correct and that the engine breather hoses are clear and undamaged.
2 If these checks fail to reveal the cause at the problem, the vehicle should be taken to a Fiat dealer or suitably-equipped garage for testing. A diagnostic socket is located below the passenger compartment fusebox in which a fault code reader or other suitable test equipment can be connected. By using the code reader or test equipment, the engine management ECU (and the various other system vehicle system ECUs) can be interrogated, and any stored fault codes can be retrieved. This will allow the fault to be quickly and simply traced, alleviating the need to test all the system components individually, which is a time-consuming operation that carries a risk of damaging the ECU of Fiat Punto.


3 Experienced home mechanics with a considerable amount of skill and equipment including a tachometer and an accurately calibrated exhaust gas analyser) may be able to check the exhaust CO level and the idle speed. However, if these are found to be outside the specified tolerance, the car must be taken to a suitably-equipped garage for further testing. Neither the mixture adjustment (exhaust gas CO level) nor the idle speed are adjustable, and should either be incorrect, a fault may be present in the engine management system.