How To Test The Starter Motor (1995-1999 3.1L V6 Chevrolet Lumina, Monte Carlo)

TEST 6: Bypassing The Anti-Theft Relay

So far you have:

• Confirmed that the starter motor does crank the engine but only when using a remote start switch (TEST 1).
• That the starter motor is not receiving a START signal (TEST 2).
• That terminals A2 and C2 (of the anti-theft relay connector) are receiving 10 to 12 Volts DC (TEST 4, TEST 5).

In this test section, we're gonna' bypass the anti-theft relay and then turn the key to the START position to see if the starter motor cranks the engine.

To be a bit more specific, we're gonna' jumper together terminals A2 and C1 of the anti-theft relay's connector with a jumper wire.

IMPORTANT: The jumper wire ends, that you'll need to insert into the relay's terminals can not be thicker that the male spade terminals of the anti-theft relay itself. Inserting anything thicker, than the male spade terminal of the relay, will damage the female terminal. This is a head-ache you want to avoid!

CAUTION: Double check that you're inserting the jumper wire into the correct female terminals!

These are the test steps:

1. 1

   Insert one end of your jumper wire into female terminal A2.
   
   IMPORTANT: Terminal A2 connects to the thicker yellow (YEL) wire of the relay connector.

2. 2

   Insert the other end of your jumper wire into female terminal C1.
   
   IMPORTANT: Terminal C1 connects to the purple (PPL) wire of the relay connector.

3. 3

   Turn the key to the START position to crank the engine.

4. 4

   You'll get one of two results:
   
   1.) The starter motor will crank the engine.
   
   2.) The starter motor will NOT crank the engine.

Let's examine your test result:

CASE 1: The starter motor cranked the engine. This is the correct and expected test result.

It looks like either the anti-theft relay is bad or the anti-theft system is activated. Continue to: TEST 7: Testing The STARTER ENABLE Signal (Anti-Theft Relay).

CASE 2: The starter motor DID NOT crank the engine. Recheck your jumper wire connections and repeat the test.

If the starter motor still does not activate, then the most likely causes are:

• Damaged 'S' terminal stud (on the starter motor solenoid).
• Corrosion on the 'S' terminal stud (on the starter motor solenoid).
• An open-circuit problem in the PPL wire between the relay connector and the starter motor.

TEST 7: Testing The STARTER ENABLE Signal (Anti-Theft Relay)

The Theft Deterrent Module provides Ground to female terminal A1 of the anti-theft relay's connector.

This Ground is considered the STARTER ENABLE signal, since once it's provided, the anti-theft relay enables the starter motor to start cranking the engine.

In this test section, we're gonna' check for the presence of Ground when the key is turned to the START position.

If Ground is present (with the key in the START position), then you can conclude that the relay itself is bad and replacing it will enable the starter motor.

If Ground IS NOT present (with the key in the START position), then you can conclude that the anti-theft system is activated and is behind the disabled starter motor.

IMPORTANT: If you probe the front of the indicated female terminals with your multimeter test leads, probe them gently to avoid damaging them. I recommend that you probe the terminal from the back of the relay connector.

CAUTION: Do not directly pass battery 12 Volts to female terminal A1 of the relay connector, or you'll fry the anti-theft module. The suggested multimeter voltage test, described in the test instructions, is a safe way to confirm the presence of Ground in the terminal.

These are the test steps:

1. 1

   With the red multimeter test lead, gently probe female terminal C2.

2. 2

   With the black multimeter test lead, gently probe female terminal A1.

3. 3

   Turn the key to the START position to crank the engine.

4. 4

   You'll get one of two results:
   
   1.) The multimeter will register 10 to 12 Volts if Ground is present in terminal A1.
   
   2.) The multimeter will register 0 Volts if Ground IS NOT present in terminal A1.

Let's examine your test result:

CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct and expected test result and it lets you know that the anti-theft module is enabling the starter motor.

You can conclude that the anti-theft relay is bad if you have confirmed that:

• The starter motor does crank the engine when using a remote start switch (TEST 1).
• The starter motor is not receiving a START signal (TEST 2).
• Terminals A2 and C2 (of the anti-theft relay connector) are receiving 10 to 12 Volts DC (TEST 4, TEST 5).
• The starter motor cranked the engine when jumpering terminals A2 and C1 (TEST 6).
• In this test section, terminal A1 has Ground with the key in the START position.

CASE 2: The multimeter registered 0 Volts DC. This test result lets you know that the anti-theft module is disabling the starter motor.

The most likely cause of this problem is:

• A bad key (the resistor pellet on the key has worn out).
• A bad ignition switch (the switch can no longer read the resistance of the pellet on the key).

Although it's beyond the scope of this tutorial, your next step is to troubleshoot the anti-theft system (PASS-Key II).

Location Of The Anti-Theft Relay

On all vehicles covered by this tutorial the anti-theft relay is located above the glove box and behind the passenger-side dash airbag.

You'll need to remove the glove box to be able to access the anti-theft relay and more importantly its electrical connector.

To follow the tests in this tutorial, you'll need to remove the anti-theft relay to be able to disconnect it from its electrical connector (to test its inputs).

To remove the anti-theft relay, it's super critical to use a 7mm ratchet wrench on the 7mm screw that attaches the relay do the instrument panel frame.

Without this 7 mm ratchet wrench (see photo 3 of 3 in the image viewer above), it's next to impossible to remove the anti-theft relay to disconnect it from its connector.

More 3.1L V6 Chevrolet Lumina (Monte Carlo) Diagnostic Tutorials

You can find a complete list of 3.1L V6 test tutorials here: GM 3.1L V6 Index Of Articles.

Here's a list of articles you'll find there:

• How To Test The Fuel Pump (1995-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).
• How To Test The Fuel Injectors (1995-1999 3.1L Chevrolet Lumina, Monte Carlo).
• How To Test The 24X Crankshaft Position Sensor (1995-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).
• Fuel Pump Wiring Diagram (1998-1999 3.1L V6 Chevrolet Lumina, Monte Carlo).