Possible malfunctions of the engine management system, their causes and remedies (Electrical equipment / Engine management / Ford Focus 2 2004-2010)

Cause of malfunction	Remedy
The starter rotates the crankshaft at normal speed, but the engine does not start for a long time. After starting, the engine stops immediately
Faulty ignition system	Check the voltage in the secondary circuit; condition of the spark plugs (soot, electrode moisture, cracks or chips in the insulator, the condition of the electrodes and the gap); ignition coils, high voltage wires and protective caps; reliability of electrical contact in the connectors of the ignition coil; reliability of EEU contacts with «weight»
Faulty fuel injection system	Cm. «Engine power system», With. 113
The engine does not develop rated power. Vehicle accelerates sluggishly when partially depressing the accelerator pedal
Faulty ignition system	Check the voltage in the secondary circuit with a special tester. Check the operation of the ignition timing system with a stroboscope
There is no reliable contact between the computer and «weight»	Check the condition, cleanliness and tightness of the terminal connections «massive» ECU wires
Low voltage in the on-board network - the generator is faulty	Check the voltage at the output «B+» generator, which must be at least 13 V
Knocking knocks in the engine when accelerating the car
Mismatch of the glow number of spark plugs installed on the engine	Replace the spark plugs with the recommended ones for this engine model
Damage to high voltage wires	Check the resistance of the high voltage wires with an ohmmeter. It should not exceed 30 kOhm. An ohmmeter is connected to the tips of the tested wire
Malfunction of the coolant temperature sensor or its electrical circuit	Check and, if necessary, replace the sensor. Check the contact connections in the wiring of the sensor circuit
Lack of quick engine response to a change in throttle position, especially when starting the car from a standstill and at the beginning of acceleration
Faulty throttle position sensor	Replace sensor
Low voltage in the on-board network - the generator is faulty	Check the voltage at the terminal with a voltmeter «B+» generator with the engine running, which should be more than 13 V
Faulty mass air flow sensor	Replace sensor
Faulty high voltage wires	Check wire resistance with an ohmmeter. connecting it to the tips of the tested wire. Resistance should be no more than 30 kOhm
Dirty spark plugs	Clean the spark plugs with a sandblaster or replace
Contamination of ignition devices	Remove moisture and dirt from high voltage wires and ignition coils
Unreliable contact of ignition devices with «weight»	Check the contact connections of the wires of the ignition system with «weight». Clean and tighten wire lugs
The engine runs intermittently. Jerks of the car with increasing engine load. Irregular exhaust noise
Faulty spark plugs	Start the engine. After setting the idle speed, remove the high voltage wire from one spark plug using pliers with insulated handles. Disconnect the wires from the candles one by one and for a short time so as not to damage the catalytic converter. If disconnecting the wire from the spark plug does not cause a sharp decrease in engine speed, then the spark plug is faulty and needs to be replaced
High voltage wiring fault	Measure the resistance of the wires between the tips with an ohmmeter, which should be no more than 30 kOhm
Uneven engine idling, accompanied by increased vibration and stops
Lean air-fuel mixture due to an increase in the voltage of the oxygen concentration sensor signal due to the formation of deposits on the sensor bulb	If there is a white powder coating on the sensor, replace it
Throttle stuck open	Eliminate sticky throttle
Malfunction of the coolant temperature sensor or its electrical circuit	Check and, if necessary, replace the sensor. Check the contact connections in the wiring of the sensor circuit

Possible malfunctions of the engine management system, their causes and remedies

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