Testing and troubleshooting the ignition coils on your Nissan Altima or Sentra is not hard! This article will take you through the whole testing process step by step. You'll be able to easily diagnose a misfire condition on your Altima and/or solve a misfire code that may be lighting up the check engine light on your Altima or Sentra's instrument cluster.
Every step is explained in plain English and with photos to guide you every step of the way. Also, all tests are on-car tests and done without a scan tool. To find out if this info applies to your Altima or Sentra, check out the list of Nissan Altima and Sentra years at the bottom of this page.
Symptoms Of A Bad Ignition Coil
Beside the check engine light annoying you, your Altima or Sentra may also experience one or several of the following symptoms:
- Misfire codes that light up the check engine light (CEL) on your instrument cluster.
- P0300, P0301, P0302, P0303, P0304.
- Engine misfire that DOES NOT light up the check engine light (CEL).
- Smell of unburned gasoline coming out of the tailpipe.
- Rotten egg smell coming out of the tailpipe. This is due to the unburned gasoline from the misfiring cylinder over loading the catalytic converter.
- Really bad gas mileage.
- Lack of power as you accelerate the vehicle down the road.
What Tools Do I Need?
To test the Coil-On-Plug (COP) ignition coils you don't need an automotive diagnostic scan tool (commonly known as a scanner or scan tool). You do need a few basic tools and these tools won't break the bank.
- An HEI spark tester
- This inexpensive spark tester is a MUST have tool to be able to correctly diagnose the Coil-On-Plug ignition coils on your GM vehicle with the info and tests in this article.
- Battery jump start cables.
- A digital multimeter.
- A helper.
- You'll need someone to help you crank the engine while you perform the tests in the engine compartment.
- A repair manual.
- For whatever remove and replace info you'll need that is not covered by this article.
Circuit Descriptions: Nissan Ignition Coil Connector
The Nissan Altima/Sentra's ignition coil is a three wire Coil-On-Plug ignition coil.
Which means that each ignition coil has a transistor inside that plays the role of an ignition control module (ICM). Below are the circuit descriptions of each wire (circuit):
- Circuit labeled 1:
- Power (12 V) Circuit.
- Circuit labeled 2:
- Ground Circuit.
- Circuit labeled 3:
- Triggering Signal Circuit.
You don't have to worry about the color of the wires as long as you're able to identify the circuit using the photos in each test step.
Do's and Don'ts And Precautions
The tests that you're about to learn/do in this article are very easy and simple to do. Some of them have to be performed with the engine cranking, so you still have to be on your toes and remain alert. Use common sense and take all necessary safety precautions. Here are some more suggestions:
- Do not use a regular spark plug instead of a spark tester to test for spark.
- Do not remove the ignition coil from the spark plug while the engine is cranking to test for spark. This method for testing for spark can ruin the ignition coil, and now you have another problem to worry about.
- Start your diagnostic from TEST 1, do not skip around from test to test unless instructed to do so by the TEST you are currently on.
- Once again, use the recommended/indicated tools for all of your tests.
Nissan Altima And Sentra That Use This Ignition Coil
- Nissan
- Altima 2.5L
- 2002, 2003, 2004, 2005, 2006.
- Sentra 2.5L
- 2002, 2003, 2004, 2005, 2006.
- Altima 2.5L
