You can test the starter motor on your 2.5L Nissan Sentra (or Altima) in three steps.
I'll explain how in a step-by-step way. You'll be able to find out if the starter motor is defective (or not) without having to remove it to bench test it.
Contents of this tutorial at a quick glance:
- Important Safety Tips And Precautions.
- Symptoms Of A BAD Starter Motor.
- Tools Needed To Test The Starter Motor.
- TEST 1: Applying 12 Volts To The Starter Motor S Terminal.
- TEST 2: Verifying The Start Signal.
- TEST 3: Voltage Drop Testing The Battery (+) Cable.
- More 2.5L Nissan Tutorials.
Important Safety Tips And Precautions
TIP 1: As mentioned at the beginning of the tutorial, you don't have to remove the starter motor to test it. In the illustrations I've made you'll notice that it's removed, but this is just to facilitate the explanation of your test connections.
If the starter motor is already removed, you can bench-test it and the following tutorial will help you: Bench Testing The Starter Motor.
TIP 2: Your Nissan Sentra's battery should be fully charged before beginning any of the tests in this tutorial. Performing the tests with a less than fully charged battery may give you a false test result.
It's also very important that the battery terminals and post be absolutely clean before starting any of the test.
TIP 3: If your Nissan Sentra (Altima) comes equipped with a standard transmission, be sure and place it in neutral before starting any of the test. Don't forget to activate the parking brake.
TIP 3: You may need to raise your vehicle, with a jack, to access the starter motor. Don't trust the jack to keep your pick up or SUV up in the air, use jack stands!
Symptoms Of A BAD Starter Motor
The most common end result of a bad starter motor is that the engine in your 2.5L Nissan Sentra will not turn over when you turn the key to crank and starter it.
The other type of problem is an intermittent failure that makes the starter motor fail some of the time.
Intermittent starter motor problems can be a challenge to resolve. The most important thing to remember, in this type of starter motor problem, is that you'll have to wait till the engine is not cranking to test it.
You'll see one of the following symptoms when the starter motor fails:
- When you turn the key to start your the engine, nothing happens.
- Jump starting the engine doesn't make it crank over.
- The battery has been charged and/or replaced and still your Nissan Sentra does not crank.
- When you turn the key to crank the engine, all you hear is a small knock and nothing else.
Tools Needed To Test The Starter Motor
Testing the starter motor on your 2.5L Nissan Sentra (Altima) doesn't require expensive or exotic diagnostic tools. Here's a list of the tools you'll need to successfully test it:
- Remote starter switch.
- If you'd like to see what a remote starter switch looks like, you can follow this link: Actron CP7853 Remote Starter Switch.
- You can either buy this tool online or you can buy it at your local auto parts store (AutoZone, O'Reilly, Pepboys, etc.).
- Multimeter or a 12 Volt automotive test light.
- If you don't have a multimeter or need to upgrade yours, check out my recommendation here: Buying A Digital Multimeter For Automotive Diagnostic Testing.
- A wire piercing probe.
- This tool is not an ‘absolute must have tool’ but I can tell you from experience that it makes it a whole lot easier to probe the S terminal wire for the start signal.
- If you'd like to see what this tool looks like, you find out more about it here: Wire Piercing Probe Tool Review (Power Probe PWPPPPP01).
- A helper.
As mentioned before, the tools you need to test the starter motor won't break the bank. OK, let's turn the page and get starter with the first starter motor test.