P1391
Read the instructions below then
start the fault diagnostic procedure.
Symptom: CHECK ENGINE.
Running unevenly and misfiring.
Cylinder 1 Misfire Detected. Catalyst Damaging. Fuel Level Low.
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 temperatures must exceed -7°C.
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Engine started. Fuel level below 4 litres. Main relay voltage exceeding 10V. Ignition discharge module combustion signals registered. The number of missing combustion signals is accumulated for each cylinder during 200 engine revolutions. The total number of accepted misfires during 200 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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Provided the fault criteria are not fulfilled during the driving cycle the OK report occurs at ignition off 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 section
Fault handling I, catalytic converter harmful misfiring
for more information.)
Diagnostic help
If any other trouble codes have been generated, check whether fault diagnosis should start with them. Drive the car in the load and engine speed range shown by Freeze Frame. If the engine does not misfire, the trouble code was probably due to the fuel level being too low. Drive the car so that the catalyst diagnosis is performed. If necessary, change the catalytic converter.
If the engine misfires during test driving, conduct a general inspection of connectors and hoses, and then a thorough check of compression, ignition and fuel system.
Functions in the diagnostic tool related to the fault:
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Diagnostic status for the diagnosis.
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Misfire counter for the relevant cylinder.
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Activating misfire counter reset.
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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 activations under
Menu "Activation"
for more information.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.
