How To Test The Starter Motor (1989-1994 3.1L V6 Chevrolet And Pontiac Vehicles)

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.

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.

STARTER MOTOR BENCH TEST: The following link will help bench test the starter motor off the vehicle:

• How To Bench Test A Starter Motor (Step By Step)

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:

• Jack.
  • 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 see it (and buy it) here: Innova 3630 Remote Starter Switch (Amazon affiliate link).
  • You can either buy this tool online or you can buy it at your local auto parts store (AutoZone or O'Reilly Auto Parts, 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 (it's the one I use): Tekpower TP8268 AC/DC Auto/Manual Range Digital Multimeter (Amazon affiliate link).
• 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: Innova 3630 Remote Starter Switch (Amazon affiliate link).

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:

1. 1

   Raise the front of your vehicle and place on it jack stands (to gain access to the starter motor).

2. 2

   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.

3. 3

   Attach one end of the remote starter switch to the battery positive (+) post.

4. 4

   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.

5. 5

   Reconnect the battery negative (-) cable to the battery negative (-) post.

6. 6

   Apply 12 Volts to the 'S' terminal wire of the starter motor starter solenoid with your remote starter switch.

7. 7

   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.

• Go to: TEST 3: Voltage Drop Testing The Battery (+) Cable.

TEST 2: Verifying The 12 Volt Start Signal

As stated in TEST 1, when you turn the key to crank and start the engine, the starter motor receives a 12 Volts activation signal.

Now your next step, and the focus of this test section, is to verify that the activation signal is present in the wire connected to the S terminal when your helper turns the key to the START position.

You'll verify the presence of the activation signal with a multimeter voltage test.

NOTE: You can perform this test with the 'S' wire connected or disconnected to the 'S' terminal.

These are the test steps:

1. 1

   Raise and place the front of the vehicle on jack stands (if it isn't already).

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Ground the black multimeter test lead directly on the negative (-) battery terminal using a jump start cable.
   
   You can also Ground it on the engine, if you can find a clean, unpainted and rust-free spot of metal.

4. 4

   Connect the red multimeter test lead to the 'S' terminal wire using an appropriate tool.
   
   Don't know which wire is the 'S' terminal wire? This is the one that connects to the smaller of the three studs on the starter motor solenoid.
   
   The 'S' terminal wire (circuit) is the one that delivers the Start (Crank) signal from the ignition switch.

5. 5

   Have your helper turn the key to crank the engine when the test is setup.

6. 6

   Your multimeter should read 10 to 12 Volts DC.

OK, let's see what your test results mean:

CASE 1: Your multimeter registered 10 to 12 Volts. This is the correct and expected test result and it confirms that the starter motor is receiving its activation signal.

Now, in most cases, you could stop here and replace the starter motor and be done. But, I suggest one more test so that you can be absolutely sure there isn't another issue to deal with.

Your next test is to voltage drop test the battery positive (+) cable. This is a very easy and simple test to do. Go to: TEST 3: Voltage Drop Testing The Battery (+) Cable.

CASE 2: Your multimeter DID NOT register 10 to 12 Volts. This test result lets you know that the starter motor isn't receiving an activation signal.

Although finding out why this activation signal is missing is beyond the scope of this tutorial, the most likely causes are:

• A bad starter motor relay.
• A bad park-neutral safety switch.
• A bad clutch pedal switch.
• A bad ignition switch.
• An anti-theft system fault (if equipped).

TEST 3: Voltage Drop Testing The Battery (+) Cable

As you already know, the starter motor draws all the current to crank the engine from the battery.

The wire that supplies this power to the starter motor is the heavy gauge cable that attaches to the BAT terminal of the starter motor solenoid.

In the photo above, the arrow with the "+" symbol indicates the BAT connection of the solenoid.

A common problem is the battery cable's terminals corroding on one or both ends, causing a false-contact connection problem.

Corrosion developing on either terminal end will prevent the starter motor from receiving all of the battery's current and won't crank the engine.

So, in this test section, you'll perform a simple multimeter voltage drop test to check the condition of the cable. The result of your voltage drop test will show if the starter is getting the battery's full power.

Let's begin:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Attach the red multimeter test lead to the positive (+) battery post. The positive (+) battery post must be clean and corrosion-free.
   
   You may need two helpers for this test step, since someone will have to hold the red multimeter test lead onto the battery positive (+) terminal bolt and someone else inside the vehicle (to crank it when everything is set up).

3. 3

   Place the black multimeter test lead on the starter motor solenoid stud that connects to the battery positive (+) cable (see illustration above).
   
   The orange arrow with the plus (+) sign, in the illustration above, points to this stud.
   
   Maintain the black multimeter test lead in this position throughout the next step.

4. 4

   When everything is ready, have your helper turn the key to crank the engine.
   
   Although the starter motor won't crank the engine, your helper has to turn the ignition switch to start the engine for the voltage drop test to work.

5. 5

   The multimeter should register 0.5 Volts or less (0.5 V = 0 Volts).
   
   If there's a problem in the wire, your multimeter will register some voltage, usually 5 Volts or more.

Let's take a look at what your results mean:

CASE 1: Your multimeter indicated NO voltage drop (which is 0.5 Volts or less). This is the correct test result and it confirms the starter motor is receiving full battery power to crank the engine.

You can conclude that the starter motor is bad and needs replacement if you have:

• Confirmed that the starter motor does not crank the engine (TEST 1).
• Confirmed that the starter motor is receiving an activation signal (TEST 2). If you haven't done this test yet, please do so now.
• Confirmed, in this test section, that the battery positive (+) cable does not have a voltage drop issue.

Now, before you remove the starter motor, do one more important thing:

• Turn the engine manually (using a 1/2 ratchet and the appropriate socket on the crankshaft pulley bolt). This will check to see if the engine is mechanically locked up (or not).

If you'd like to bench test the starter motor (after removing it). You can find the step-by-step instructions here:

• How To Bench Test A Starter Motor (Step By Step).

CASE 2: Your multimeter registered 5 Volts or more. This result confirms that the starter's battery wire has corrosion or a false-contact issue (and that's not a good thing).

The issue causing the voltage drop in the wire will prevent the battery's total amperage output from reaching the starter motor.

You should thoroughly clean both ends of the battery positive (+) cable to solve this problem.

I recommend using sandpaper to clean the cable's terminals. Once both ends of the battery positive cable are clean, reconnect everything and try cranking the engine.

If cleaning the cable ends solves the voltage drop issue, the starter motor will now crank the engine.

More 3.1L Chevrolet And Pontiac Diagnostic Tutorials

You can find a complete list of 3.1L Chevrolet and Pontiac tutorials in this index:

• GM 3.1L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• How To Test The Fuel Pump (1990-1994 3.1L V6 Chevrolet And Pontiac Vehicles).
• How To Test The TPS (1990-1994 3.1L V6 Chevrolet And Pontiac Vehicles).
• How To Test The Alternator (1990-1994 3.1L V6 Chevrolet And Pontiac Vehicles).
• How To Test The Engine Compression (3.1L V6 Chevrolet And Pontiac Vehicles).