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Troubleshooting / Engine Will Not Crank

Car Engine Will Not Crank Over

The electrical system of your car has several different voltage and amperage demand systems. The engine starter circuit is designed to carry 12 volts at high current (Amperage). This is why a battery cable is larger in diameter compared to other wires in the electrical system. When the ignition key is activated the starter will turn the engine over. If it doesn't we have listed below some of the most popular causes for starter non-operation.

Troubleshooting Procedure

A. Test Electrical System Voltage. The best way to test for electrical system voltage is to use a voltage meter (voltmeter). Attach the voltmeter leads to the positive and negative terminals of the battery. To check a battery surface voltage, remove the positive terminal protective cover and connect the +positive side meter lead (red) to the positive side battery terminal then connect the - negative (black) side meter lead to the negative battery terminal. With the vehicle not running and sitting over night the battery voltage should be between 12.4 and 12.6 volts. To test the system without a volt meter activate the headlights, if they illuminate brightly the electrical system probably has sufficient voltage. If the headlights are dim or not working the battery charge is either low or the battery has failed and needs replacing.

Checking Battery Voltage
Checking Battery Voltage

B. Starter Voltage/Amperage Draw Test. Turn the headlights on and observe, activate the ignition key to crank the engine over. If the headlights stay bright the electrical circuit is not connected, therefore no voltage drop. A popular reason for this is the winding inside the starter has shorted or the starter armature brushes have worn out and replacement is recommended. If headlights dim way down this indicates your battery is weak and needs either replacement or recharge. As a rule of thumb, a typical car battery will last three to four years before replacement is needed.
 
C. Check Neutral Safety Switch/Clutch Safety Switch. A neutral or clutch safety switch is used to disengage the electrical circuit from the ignition key to the starter motor as a safety device. Automatic transmission vehicle gear selector needs to be either in park or neutral before the engine will crank (Make sure the parking brake is activated). If the gear selector is in any of the other gear sections the engine will not crank over. A standard transmission vehicle the clutch pedal needs to be fully depressed before the engine will crank over. To test this circuit an automotive test light is needed. Attach one end of the test light to engine ground and the other end to the starter trigger terminal of the starter solenoid (small wire). The test light should illuminate when the ignition switch is activated (Crank engine over). If the test light illuminates the starter motor/solenoid has failed and needs to be replaced. If the test light does not illuminate suspect a neutral safety switch or clutch safety switch. A wiring diagram is needed to trace power from the ignition switch through the safety switch and down to the starter solenoid. Replace failed components as needed and recheck system.

Starter Solenoid
Starter Solenoid (appearance may vary)

D. Testing Anti Theft Device. Some cars have an anti theft system that will not allow the starter to operate. If this system malfunctions the car will not crank over even after the alarm has been disabled. To test this system, observe the "Security" light on the dash or instrument cluster. If this light flashes while the key is being activated the security system is in failsafe mode. If you have an aftermarket alarm system in your car and you think it may be the problem locate the main system interrupted relay and bypass main control circuit. If car cranks over the alarm system has failed and replacement is needed.

E. Check for Internal Engine Damage. If your engine has had a major malfunction it will not turn over. To check for this condition install a socket wrench on the front crankshaft bolt, then try to rotate. The engine will turn with a certain degree of difficulty but it should rotate a full 360 degrees (clockwise). If the engine doesn't turn disassembly is required, repair as needed and reassemble.

For exact specific repair procedures for any of the steps above visit our online repair manual page.

Troubleshooting / Engine Will Not Crank

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