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Testing the ignition coil on your Nissan car or truck is a project that you can do at home and save yourself a large diagnostic charge at the dealer. Though the coil produces electricity, testing it involves resistance of the coil windings. You can check the resistance with a multi meter that allows you to test ohms or a dedicate ohms meter. If you do not have a multi meter, you can purchase one in the electrical department at many auto parts stores or home centers.
Step 1
Remove the negative battery cable from the battery with a wrench or socket and ratchet. Isolate the cable to ensure it is not going to contact the battery while you are working.
Step 2
Find the coil. The coil may be a cylinder or a square block but it will always have a high-tension cable attached to it. This cable looks like spark plug wire and runs to the center of the distributor cap.
Step 3
Disconnect the high-tension cable from the coil by pulling it straight off the coil tower. Lay it aside and disconnect the wires attached on either side of the coil tower. Use a wrench to loosen the nuts and remove them along with the wires. If the coil has a plug-in connector instead of the studs, unplug the connector for the coil after releasing any locking tab on the connector.
Step 4
Place one lead from the multi meter on the negative post or terminal of the coil. Place the second lead on the positive post or terminal and note the reading on the meter. This is the primary resistance of the coil and should be between .7 and 1.7 ohms. Some cars may produce different readings so check with the dealer for values if you are not sure.
Step 5
Move the lead from the positive terminal to the high-tension terminal while leaving the other lead on the negative post or terminal. Note the reading on the meter. This is the secondary resistance and should be between 7500 and 10500 ohms on most cars.
Reconnect the connections to the coil if the test indicates a properly functioning unit. If the coil shows values outside the ranges listed, the coil needs further testing or replacing.
Items you will need
- Digital multi meter
- Wrench
