P0303
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
Running unevenly and misfiring.
Cylinder 3 Misfire Detected.
Fault symptoms
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Running unevenly and misfiring.
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On-Board Diagnostics
Type of diagnosis:
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Continuous. But interrupted when fault criteria fulfilled and will not restart until next driving cycle.
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Enable criteria:
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General conditions for this trouble code: Atmospheric pressure must exceed 72 kPa and the engine coolant and intake air temperature must exceed -7°C.
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Engine running. Main relay voltage exceeding 10V. Ignition discharge module combustion signals registering. The number of missing combustion signals is accumulated for each cylinder every 1000 engine revolutions. The total number of accepted misfires during 1000 engine revolutions is specified in a load and engine speed-dependent matrix.
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Fault criteria:
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Number of missing combustions exceeding number of accepted misfires.
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Dependents:
System reaction to a fault:
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Under high engine loads, closed loop will be blocked while misfiring occurs.
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OK report:
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Under the condition that the fault criteria is not fulfilled during the driving cycle the OK report occurs at ignition before the engine stalls. Two types of OK reports can be given: Type 1: If a DTC is already stored for the diagnosis and similar operating conditions have occurred (coolant temperature above or below 71°C, engine speed 375 rpm and load 10%). Type 2: If there is no DTC stored for the diagnosis or similar operating conditions have not occurred
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Fault handling:
(See “Fault diagnosis, general” for more information.)
Diagnostic help
If any other trouble codes have been generated, check whether fault diagnosis should be started on any of them first. Read Freeze Frame and change spark plugs.
Then check the compression, ignition and injector for the relevant cylinder.
Diagnostic tool functions related to this fault are:
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Diagnostic status for the diagnosis.
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Misfire counter for the relevant cylinder.
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Activation of misfire counter resetting.
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Activating ignition trigger for relevant cylinder.
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Activating injector test for relevant cylinder.
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See also the description of activating functions under ”Fault diagnosis, general” for more information.
Check the wiring
Jiggle the leads and in-line connectors at various points and in different directions to detect any intermittent breaks or short circuits in the wiring. Observe the multimeter, test lamp or diagnostic tool while doing this.
