DTC 4-5-4 Misfire Cylinder 4
4-5-4 MISFIRE CYLINDER 4Preconditions for DTC
^ If the ECM registers more than approx. 6 - 50% misfiring during 1000 engine revolutions (2500 ignition sequences), the ECM will check if this misfiring comes from one specific cylinder or from different cylinders.
^ If only one cylinder exceeds the limit, DTC 5-4-3 is set first, followed by one of DTCs 4-5-1, 4-5-2, 4-5-3, 4-5-4 or 4-5-5 depending on the relevant cylinder.
^ If several cylinders exceed the limit, DTC 5-4-3 and 5-4-2 are set as well as a DTC for the relevant cylinder.
Substitute value
^ Fuel trim with rear Heated Oxygen Sensor (HO2S) shut off.
Fault sources:
^ Defective spark plugs, ignition cables, distributor cap/rotor, ignition coil or flywheel/tooth wheel.
^ Faulty spark plug.
^ Blocked/leaking injector.
^ Uneven compression.
^ Leakage between cooling system and cylinder.
^ Moisture, flashover in ignition system's high-tension section.
^ Intermittent break, intermittent short circuiting to ground, intermittent short circuiting to voltage supply, contact resistance or loose connection in ignition system's low-tension section, in injector circuit or fuel pump circuit.
^ Too much engine oil.
^ Air leakage.
^ Fuel pressure and residual pressure.
Fault sources not included in the fault tracing process, but which may still set a DTC:
^ Fuel stoppage.
^ Insufficient fuel level, resulting in fuel starvation.
^ Water in the spark plug recesses.
^ Incorrect fuel or dirty fuel.
^ Repeated cold starts whereby the engine is never given sufficient time to reach normal operating temperature between each start.
^ Puncture in a front tire.
Fault symptoms
^ Engine does not start, or is difficult to start.
^ Engine runs unevenly at idling speed, or jerks severely while driving.
^ Poorer performance.
^ Higher emissions.