ad esempio, queste sono delle indicazioni per perdite di colpi:
Diagnostic Aids
Important:
• Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
• For any test that requires probing the PCM or a component harness connector, use the Connector Test Adapter Kit J 35616 . Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Wiring Systems.
• Running the vehicle out of fuel causes sufficient misfire to set DTC P0300. A vehicle that is out of fuel may have DTCs P0461/P1431 also set.
• A restricted fuel filter can cause sufficient misfire to set DTC P0300. Refer to Fuel System Diagnosis .
• A misfire that only occurs during certain conditions may be difficult to locate. Observe freeze frame and/or failure records to determine when the DTC set.
• Excessive vibration from sources other than the engine could cause a misfire DTC. The following are possible sources of vibration:
- Variable thickness brake rotor
- Propeller shaft not balanced
- Certain rough road conditions
• Observe, if more than one cylinder is mis-firing, the scan tool may only display one cylinder mis-firing. This is not apparent until the repair is completed. Also, if an ignition coil/module ground circuit is open for one side of the engine, the scan tool may only display 2 or 3 cylinders mis-firing. Inspect the ground circuit for the ignition coil/modules on the cylinder bank of the engine that has more than one cylinder mis-firing.
• A misfire may not be apparent at idle. The misfire may only occur above idle under a load. Road test the vehicle and monitor the misfire current counters.
• For an intermittent condition, refer to Symptoms .
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2.
The Misfire Current Counters will not increment if certain DTCs set at the same time or after DTC P0300 sets. Refer to Conditions for Running the DTC P0300 for applicable DTC list.
If more than one cylinder is misfiring, the Misfire Current Counters may increment for only one cylinder. Example: Cylinders 1 and 8 are both misfiring, yet only cylinder 8 increments on the Misfire Current Counter.
If one of the injector fuses is open, only two or three Misfire Current Counters may increment for the corresponding side of the engine.
Wetting down the secondary ignition system with water from a spray bottle may help locate damaged or deteriorated components. Look/listen for arcing or misfiring as you apply the water.
If the Misfire Current Counters are incrementing and there is no apparent misfire, an erratic CKP sensor signal could be the cause. Perform the diagnostic table for DTC P0335 first if this condition is suspected.
If a misfire is present and you suspect a fuel control concern, force the fuel system into Open Loop using the scan tool and allow the engine to run for a few minutes. If this eliminates the misfire, refer to any fuel control related DTCs which are set. If no other DTCs are set, refer to the Engine Scan Tool Data List.
4.
The cylinder with the more significant misfire may cause another cylinders counter to increment only by a small amount.
10.
If the engine misfire moves with the spark plug, this is good indication that you should replace the spark plug.
12.
An engine mechanical condition can cause a spark plug to gas foul. Inspect for loose rockers, collapsed lifters or worn camshaft lobes.
17.
If the customers concern is the MIL is flashing, this indicates that a Catalyst Misfire has occurred. Drive the vehicle in the conditions to run the catalyst diagnostic.
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