All the mentioned components are covered by an extended warranty mandated by the federations; therefore, it is impossible to check or replace any of the, while still under warranty; but after the warranty expires, all with the exception of the oxygen sensor and the ECU can be checked and replaced. To inspect the EFI main relay, in engine compartment fuse panel, switch on the ignition key light, and if it has clicking sound, then relay operates fine, otherwise its resistance has to be measured. For models that were produced between 1979 and 1981 make sure there is continuity between the terminals and check the resistance; for the later models the continuity should exist and use battery voltage to check for operation. The circuit opening relay of the compressor is located in a different position in various models of the car, its operation should be examined fist and then the resistance measurement. The resistance of solenoid resistor should be the one recommended by manufacture for specific model. Most coolant temperature sensors have less resistance as the temperature rises; therefore, if the resistance does not change, replace the sensor. When it comes to the fuel cut RPM checks, the procedures vary according to the model year and involve bridging terminals and checking RPM. Continuity and resistance must be tested on the fuel pump relay and the resistor and the high temperature line pressure-up system must check whether the vacuum switching valve is operational with the right amount of resistance. The High Altitude Compensation System's sensor shall make resistance measurement, and the EGR gas temperature sensor shall be checked in hot water. The functionality of the oxygen sensor can be determined by methods such as voltage and deflections and the methods differs with the model year. It will only be appropriate to check the sub-oxygen sensor when a certain code is on while the throttle position sensor needs to be bench checked and might even need to have its continuity altered. Cam position sensor is for turbo only; ECU should be replaced only if faulty according to a dealer, and there is a detailed method on how to remove and install it.