Sooner or later, the starter motor will fail, and when it does, you'll turn the key to crank and start the engine, but nothing happens.
If this is the case in your case, this tutorial will help you troubleshoot the starter motor.
All test steps are explained step by step. Your test results will help you quickly determine whether the starter is good or bad.
NOTE: The starter motor test in this tutorial is an on-car test. The photos I'm using show the starter motor off of the vehicle only to explain the test connections better.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar El Motor De Arranque (1989-1994 3.1L V6 Chevrolet y Pontiac) (at: autotecnico-online.com).
APPLIES TO: This tutorial applies to the following vehicles:
- 3.1L Chevrolet Beretta: 1990, 1991, 1992, 1993.
- 3.1L Chevrolet Cavalier: 1990, 1991, 1992, 1993, 1994.
- 3.1L Chevrolet Celebrity: 1990.
- 3.1L Chevrolet Corsica: 1990, 1991, 1992, 1993.
- 3.1L Chevrolet Lumina: 1990, 1991, 1992, 1993, 1994.
- 3.1L Pontiac 6000: 1989, 1990, 1991.
- 3.1L Pontiac Grand Prix: 1989, 1990, 1991, 1992, 1993.
- 3.1L Pontiac Sunbird: 1991, 1992, 1993, 1994.
Important Testing Tips
TIP 1: The battery must have a full charge before starting any of the tests in this tutorial.
TIP 2: The battery cable terminals and the battery posts should be clean and corrosion-free before starting the tests.
TIP 3: Read the entire article first to familiarize yourself with the tests.
TIP 4: Use jack stands for safety. Don't trust the jack alone to keep your vehicle up in the air while you're underneath it!
TIP 5: Take all necessary safety precautions. Use safety glasses while working underneath the vehicle. Be alert and think safety all of the time.
Symptoms Of A Bad Starter Motor
As mentioned at the beginning of the tutorial, the starter's job is to crank the engine. Once the engine cranks, it should start (if it gets air, fuel, and spark).
When the starter motor fails, it generally stops working and will not crank the engine (until it's replaced).
In some cases, the starter motor fails intermittently. In other words, it'll work most of the time until it won't. Unfortunately, this cycle of intermittent no-crank failures repeats itself many times.
These intermittent problems are the most difficult to diagnose since you need to test the starter motor when it's not cranking the engine.
Tools Needed To Test The Starter Motor
Although testing the starter motor isn't complicated, and you don't require expensive diagnostic equipment, you do need a few essential tools.
Here's a list of things you'll need:
- You'll need to raise your vehicle to gain access to the starter motor.
- Jack stands.
- A 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 For 6V And 12V Automotive Starting Systems.
- You can either buy this tool online or you can buy it at your local auto parts store (AutoZone, O'Reilly Auto Parts, Pepboys, etc.).
- A 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 (at: easyautodiagnostics.com).
- 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.
TEST 1: Applying 12 Volts To The 'S' terminal
As you probably already know, the starter motor receives an activation signal when you turn the key to crank and start the engine.
This activation signal is in the form of 12 Volts supplied to the S terminal on the starter motor solenoid.
For your first test, you'll apply 12 Volts from your vehicle's battery directly to the S terminal.
The best and safest way to do this is with a remote starter switch. If you don't have one and need to buy one, you can buy it here: Actron CP7853 Remote Starter Switch For 6V And 12V Automotive Starting Systems.
If the starter motor activates (when applying 12 Volts to its 'S' terminal), you can conclude that it's functioning correctly.
IMPORTANT: Remove the key from the ignition switch for this test.
OK, these are the test steps:
Raise the front of your vehicle and place on it jack stands (to gain access to the starter motor).
Disconnect the battery negative (-) terminal.
You'll reconnect it back in one of the following steps, for now, it's a safety precaution as you set up the test.
Attach one end of the remote starter switch to the battery positive (+) post.
Attach the other end of the remote starter switch to the 'S' terminal of the starter motor solenoid.
This is easier said than done, so take your time and make sure the connection is on the 'S' terminal of the starter motor solenoid.
Also, in case you're wondering, you can leave the starter motor solenoid's 'S' terminal wire connected to the engine's wiring harness connector or not, the test will work either way.
Reconnect the battery negative (-) cable to the battery negative post.
Apply 12 Volts to the 'S' terminal wire of the starter motor starter solenoid with your remote starter switch.
You'll get one of two results:
1.) The starter will activate and will turn over the engine.
2.) The starter motor won't do a thing.
Let's take a look at what your test results mean:
CASE 1: The starter motor cranked the engine. This is the correct and expected test result.
You can conclude that the starter motor itself is OK. The next step is to see if the starter motor gets the 12 Volt activation signal on the S terminal wire. Go to: TEST 2: Verifying The 12 Volt Start Signal.
CASE 2: The starter motor DID NOT crank the engine. This usually means that your starter motor is bad and needs to be rebuilt or replaced.
I suggest voltage drop testing the battery cable (that attaches to the starter motor solenoid) to make sure the starter motor is receiving full battery power.