TEST 2: Verifying The Start Signal
There's a good chance that the 12 Volt start signal is missing if in TEST 1 the starter motor cranked the engine with the remote start switch, yet it doesn't crank the engine when you turn the ignition key.
In this section we'll check for it with a multimeter.
OK, here's what you'll need to do:
Lift the vehicle and place it on jack stands (if it isn't already up in the air). Now, while underneath it, connect the red multimeter test lead to the S terminal wire of the starter motor.
You can either test for this signal with the S terminal wire connected to the starter motor or not -your choice.
Connect the black multimeter test lead to a clean and rust-free spot on the engine or on the vehicle frame.
Here I'm going to recommend something to you: Use a battery jump start cable to Ground the black multimeter test lead to a clean Ground point on the engine. The reason why is that depending on how rusty and dirty the underneath of the vehicle, you may NOT be able to find a clean and rust-free spot to Ground the multimeter's black test lead.
Now, have your helper crank the engine.
The engine won't turn over, but the idea is to verify that the starter motor solenoid is getting the 12 Volt start signal from the ignition switch.
Your multimeter is going to register one of two results: A voltage between 10 to 12 Volts DC or no voltage at all.
Let's take a look at what your test results mean:
CASE 1: Your multimeter registered a voltage between 10 to 12 Volts. This test result lets you know the starter solenoid is receiving the start signal (crank signal).
This means that we can forget about the safety neutral switch and the ignition switch being bad. The next step is to make sure that the starter motor is getting the battery's full current (amperage) output by doing a simple voltage drop test on the battery positive cable. For this test go to: TEST 3: Voltage Drop Testing The Battery (+) Cable.
CASE 2: If your multimeter DID NOT register 10 to 12 Volts. This result exonerates the starter motor. Your starter motor is not bad.
Here's the reason why... without this 10 to 12 Volt Crank Signal, the starter motor will not crank the engine. Now, although it's beyond the scope of this article to test the neutral safety switch or the ignition switch, you have eliminated the starter motor and this means saving money by not buying a part your vehicle does not need.
TEST 3: Voltage Drop Testing The Battery (+) Cable
Corrosion on the positive battery terminal can keep the full amount of available battery current from reaching the starter motor. The end result is a starter motor can't crank the engine.
The surest way to find out if this is happening is by doing a simple and easy voltage drop test with a multimeter.
Now in case you're wondering what the heck is a voltage drop, in the case of the starter motor (and in any other electrical circuit), this is anything that causes some or all of the voltage and current that's traveling in the circuit to NOT reach its final destination.
OK, to get started, this is what you need to do:
Place your multimeter in Volts DC mode. Attach the red multimeter test lead to the center of the positive battery terminal. If the positive battery post isn't clean, clean a spot right on the top of it. It's important that the multimeter test lead make contact right in the center of the positive battery post.
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 and someone else will need to crank the vehicle while you perform the next step.
With the black multimeter test lead, touch the center of the starter solenoid stud to which the big battery cable attaches to. This stud is labeled as the Batt (+) in the illustration above. You'll maintain the black multimeter test lead in this position throughout the next step.
Now, have a helper turn the key to crank the engine from inside the vehicle. This is important, since a voltage drop test has to be done while the component in question is working (or trying to work).
OK, if all is good (no voltage drop), your multimeter will register 0 Volts (0.5 Volts is still 0 Volts). If there's a voltage drop, your multimeter will register voltage (usually above 7 Volts DC.)
Let's take a look at what your results mean:
CASE 1: Your multimeter registered 0 Volts (no voltage drop). This result indicates that the starter motor is receiving all of the battery voltage and amperage it needs to crank the vehicle.
You can conclude that the starter motor is bad only if you have:
- Confirmed that the starter motor doesn't work when you manually apply 12 Volts to the S terminal wire of the starter motor solenoid (TEST 1).
- Confirmed that the starter motor is receiving the 12 Volt start/crank signal (TEST 2).
- In this test step you have confirmed that no voltage drop exists on the battery positive cable.
I'm going to make two more recommendations to you. 1.) Before removing the starter motor, manually turn the engine using a 1/2 ratchet and the appropriate socket just to make sure the engine or the A/C compressor have not locked up and are causing the no crank condition and 2.) Bench test the starter motor after removing it. This is a super easy test to do and you can find this article by clicking here: How To Bench Test A Starter Motor (Step By Step) (at: easyautodiagnostics.com).
CASE 2: Your multimeter registered 5 Volts or more. This result tells you that a voltage drop does exist. This voltage drop can keep the starter motor from cranking the engine.
The good news is that this can easily be corrected, since a voltage drop is always caused by some sort of corrosion issue on the battery positive cable or terminals or the battery positive post.
The solution is to thoroughly clean the battery positive post and the battery positive terminal (both the end that attaches to the battery positive post and the end the connects to the starter motor solenoid).
After cleaning, try cranking the engine. If it cranks and starts, you've solved the problem and no further testing is required.
More 1.6L Nissan Tutorials
You'll find a complete list of Nissan 1.6L tutorials in the following index: Nissan 1.6L Index Of Articles.
Here's a small sample of the articles/tutorials you'll find in the index:
- How To Test Engine Compression (Nissan 1.6L, 1.8L).
- Mass Air Flow (MAF) Sensor Test Nissan Sentra 1.6L (1995-1999) (at: easyautodiagnostics.com).
- How To Test The 2000-2002 Nissan Sentra 1.8L MAF Sensor (at: easyautodiagnostics.com).
If this info saved the day, buy me a beer!