TEST 2: Verifying The 12 Volt Start Signal
If you've reached this point, you've confirmed that the starter motor activates when you apply 12 Volts directly to its 'S' terminal.
Since the starter motor isn't activating when you use the ignition key, your next step is to make sure that it receives an activation signal.
The wire that connects to the 'S' terminal delivers this activation signal (to it).
And as you're already aware, this activation signal will only be present in the wire when you turn the key to crank and start the engine.
Let's get testing:
Set your multimeter to Volts DC mode.
Disconnect the 'S' terminal from its 1-wire connector.
Connect the black multimeter test lead directly on the negative battery terminal.
Connect the red multimeter test lead to the 'S' terminal wire using an appropriate tool.
The 'S' terminal is labeled with the S arrow in the image above.
The 'S' terminal wire (circuit) is the one that delivers the Start (Crank) signal from the ignition switch.
Have your helper turn the key to crank the engine when the test is setup.
Your multimeter should read 10 to 12 Volts DC.
OK, let's interpret your test results:
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 the majority of the cases, you could stop testing 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 park-neutral safety switch.
- A bad clutch pedal switch.
- A bad ignition switch.
TEST 3: Voltage Drop Testing The Battery (+) Cable
The amperage that the starter motor needs to crank the engine over comes directly from your 1.5L Honda Civic's battery.
Corrosion or false connection issues can cause this wire to suffer a voltage drop.
This voltage drop will impede the battery's maximum amperage output from reaching the starter motor. Without the battery's total amperage output, the starter motor won't crank the engine.
In this test section, you'll perform a simple multimeter voltage drop test on the battery positive wire to make sure that all of the battery's amperage output reaches the starter motor.
IMPORTANT: The starter motor must be connected to all its connectors to perform this test.
These are the test steps:
Place your multimeter in Volts DC mode.
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).
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.
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.
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 all of the battery voltage and amperage it needs 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).
- 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) (at: easyautodiagnostics.com).
CASE 2: Your multimeter registered 5 Volts or more. This result tells you that a voltage drop does exist in the wire (and it's not a good thing).
This voltage drop will prevent the battery's total amperage output from reaching the starter motor.
Generally, a voltage drop in this wire is usually due to hidden corrosion or a false contact issue.
Your next step is to thoroughly clean both ends of the battery positive (+) cable and ensure that all connections are tight.
I recommend you use a small piece of sandpaper to clean the round terminal of the wire that connects to the starter motor battery (+) terminal. Once both ends of the battery positive cable are clean, reconnect everything and try cranking the engine. If the voltage drop was the cause of the no-crank condition, the starter motor will now crank the engine.
More 1.5L Honda Civic Tutorials
You can find a complete list of 1.5L Honda Civic tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test The PGM-FI Main Relay (1992-1995 1.5L Honda Civic).
- How To Test The Fuel Injectors (1992-1995 1.5L Honda Civic).
- How To Test For A Blown Head Gasket (1.5L Honda Civic).
- How To Test Engine Compression (1992-1995 1.5L Honda Civic).
If this info saved the day, buy me a beer!