Troubleshooting
Symptoms:
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Engine misfiring
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Engine stalling
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Vehicle failing to start
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Possible causes for failure:
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Overheating resulting in the coil conducting less voltage
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Electrical surges causing damage to the coil insulation
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Damaged electrical connectors
Testing:
As the ignition coil generates an extremely large voltage it is important that the ignition is switched off before any testing takes place.
The first step is to inspect the spark plugs. These are connected to the ignition coil, so any ignition based fault code could be down to the spark plug. The plugs are situated in the combustion chamber and are therefore subject to hostile conditions which can have a detrimental effect on the plug.
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If damaged or ‘carbon fouled’ this may result in a weak spark to the combustion chamber. If the spark is too weak this may result in a misfire. By ensuring the spark plugs are in good condition first, you are eliminating one of the most common problems. The ignition coil operates in a demanding environment so the physical condition of the coil can be an issue. Damage to the coil resin is a clear indication that the coil is faulty. If the resin is cracked the coil will not provide adequate insulation, reducing the level of voltage that the coil generates. If the voltage is not at the level required, the spark will not be able to jump the gap on the plug resulting in a misfire.
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The next step is to check the wiring connections between the battery terminal and the coil output. This will determine whether the coil is receiving any current.
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The coil can be tested for resistance using an ohmmeter by connecting it to the coil terminals. Expected resistance on coils changes based on the manufacturers specifications, these will need to be investigated to confirm the expected results. The same check can be used on ignition leads.
Other components to check:
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Ignition leads – damaged leads may prevent voltage being transferred correctly
Common Fault Codes
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P0350 Ignition Coil Primary/Secondary Circuit Malfunction
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P0351 Ignition Coil A Primary/Secondary Circuit Malfunction
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P0352 Ignition Coil B Primary/Secondary Circuit Malfunction
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P0353 Ignition Coil C Primary/Secondary Circuit Malfunction
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P0354 Ignition Coil D Primary/Secondary Circuit Malfunction
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P0355 Ignition Coil E Primary/Secondary Circuit Malfunction
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P0356 Ignition Coil F Primary/Secondary Circuit Malfunction
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P0357 Ignition Coil G Primary/Secondary Circuit Malfunction
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P0358 Ignition Coil H Primary/Secondary Circuit Malfunction
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P0359 Ignition Coil I Primary/Secondary Circuit Malfunction
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P0360 Ignition Coil J Primary/Secondary Circuit Malfunction
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P0361 Ignition Coil K Primary/Secondary Circuit Malfunction
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P0362 Ignition Coil L Primary/Secondary Circuit Malfunction
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