The fault can be something quite simple and nothing that’s going to stop the car to something quite major that will reduce engine power and possibly stop the engine
The ECU senses this and may put the car into 'limp home' mode which typically limits the revs and the amount of power available. Usually the car is safe to drive for a short distance as the mode is intended is intended to get you home without incurring any engine damage
The quickest route to repair is to have the car plugged into a diagnostic machine which will read off the fault code stored in the ECU (providing the light is still on at this point) and indicate which sensor has failed or whether the fault is more serious.
You can do a very rough and ready check yourself by unplugging sensors one at a time and seeing if any of them change the driving condition which would indicate the most recently unplugged sensor is the faulty one. This method is not foolproof though and reading a fault code off is the better method.
I have Diagnostic machine. Autoboss. And the report code. Is that the sensors at the crankshaft is bad. This sensor is by the top cylinder side at the back close to ingnition coil. The sensor is now been changed But no different.
First my vehicle is ford focus Zetec year 2000 . Am sorry the sensor is heated oxygen sensor that was changed. Not crankshaft Sensor.
Can you please get back to me
I don't I have idea of fuel relay switch .
And also I want to know the effect of cylinder head temperature sensor. Could it be that it can cause lossing of speed.