Petrol Engine Sensors

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This list and symptoms is for petrol engines only, Engine Management Light will be on if sensor fails outside its normal working parameters, example coolant sensor tells ECU coolant is 200ºC

SENSOR TYPE NORMAL SYMPTOMS HOW TO TEST
CRANKSHAFT (CPS) NON START,   OCCASIONALLY MAY CUT-OUT AND RESTART
CAMSHAFT SENSOR NORMALLY NONSTART, ECU MAY GUESS CAMSHAFT POSOSITON
COOLANT SENSOR MAY BE NONSTART IF SENSOR TELLS ECU WRONG TEMPERATURE
AIR FLOW SENSOR NORMALLY WILL START ECU WILL USE DEFALT, WILL RUN ROUGH  
MANIFOLD ABSOLUTE PRESSURE (MAP) NORMALLY WILL START ECU WILL USE DEFALT, WILL RUN ROUGH  
THROTTLE PEDAL WON'T REV, MAY BE OK AGAIN AFTER RE-STARTING  
AIR TEMPERATURE MAY UPSET STARTING AND RUNNING SLIGHTLY  
ATMOSPHERIC MAY UPSET STARTING AND RUNNING SLIGHTLY  
KNOCK (PINKING) MAY LOOSE POWER IF ECU RETARDS IGNITION TIMING  

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