P0304
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE lamp is on or flashing. Engine running unevenly during misfiring. Possibly other diagnostic trouble codes present.
Misfiring, Cylinder 4.
Fault symptoms
CHECK ENGINE lamp is on or flashing. Engine running unevenly during misfiring. Possibly other diagnostic trouble codes present.
Conditions
The number of misfires required for the exhaust emissions to reach prohibited levels or damage the catalytic converter is stored in the control module memory in a matrix that is dependent on load and engine speed. A diagnostic trouble code will be generated if the misfires exceed the value in the matrix. If more than one cylinder is misfiring, the cylinder in question is responsible for more than 95 % of the total number of misfires.
Diagnostic help
Injectors and ignition coils can be activated with the diagnostic tool.
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Select "
Injector Cyl 4 (max 30s.)" respectively "
Ignition Coil Cyl 4".
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Then, select cylinder 4 in the relevant sub-menu. Momentary misfiring can be read with the diagnostic tool.
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Select "
Data Display".
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Select "
Misfire Cyl 4"
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Checking the wiring harness. Intermittent faults may occur in connection with short circuits and open circuits. Jiggle the wiring harness at several points and in several directions to locate any problems in the wiring, including intermediate connectors. Observe the multimeter, scan tool or test lamp during the check.
Warning
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The electronic ignition system generates a tension of 40 000 volts. This tension can be lethal for people with heart problems or pacemakers. The ignition system must therefore be treated with the greatest respect.
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Important
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The ignition discharge module must be standing with the ignition coils facing down during the test so that the transformer oil will provide good insulation to the high tension part of the ignition coil.
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