Bad starter won’t crank
How to diagnose a starter
Diagnosing a starter issue is process of elimination. Here are the most common cause of a starter won’t crank condition
1) Dead battery
2) Corroded battery terminals
3) Bad ground connection
4) Bad ignition switch
5) Bad neutral safety switch
6) Immobilizer (anti-theft) problem
7) Bad starter relay in fuse box
8) Bad solenoid or bad solenoid contacts
9) Worn or shorted starter motor
How to check the battery
Check the battery’s state-of-charge using a multimeter. Battery voltage is directly related to the battery’s temperature. If you’re checking in cold weather, refer to this chart to obtain the correct voltage for the battery temperature.
If voltage is below 12.2 volts, remove the terminals and clean the cable terminals and battery posts. Reinstall the terminals and check battery voltage again. If the battery is discharged below 12.2 volts, it must be charged before proceeding.
Check for corroded battery terminals and clean
Battery terminal corrosion can be visible or invisible. Never assume the battery terminals are clean with just a visual inspection. Corrosion between the terminal and post can dramatically reduce the alternator’s ability to charge the battery.
Connect a backup power source to the OBD II port to prevent the loss of throttle body home data and to eliminate the need to reprogram the radio and power window/seat memory settings.
Then disconnect the battery terminals one at a time and use a wire brush to remove all corrosion.
Clean ground connections
A bad ground connection can cause weak starter performance or even cause a no crank condition. Clean the ground connection between the battery negative post and the engine, between the battery negative post and the fender or radiator support, between the engine and the engine compartment firewall.
Bad ignition switch
If power can’t get to the starter relay or starter solenoid, the starter motor can’t crank the engine. Remove the starter motor solenoid power wire. Connect your meter to the starter solenoid wire and the other end to ground. Turn the key to START. If you see full battery voltage on your meter, the ignition switch is good and that also proves the neutral safety switch is good. If you don’t see battery voltage, test the neutral safety switch.
Test neutral safety switch
On a vehicle with an automatic transmission, the shift lever must be in the PARK or Neutral position to allow starting. If the vehicle won’t start in PARK, move it to the NEUTRAL position and try again.
With the test leads still connected to the battery terminals, set your meter to MIN/MAX. Then crank the engine to start it. NOTE: If it starts right away and you can’t get a reading, remove the fuel pump fuse and try again.
The cranking voltage will drop. If the voltage drops below 9.6-volts, that can cause critical engine computers to stop working, resulting in a no start condition.Posted on by Rick Muscoplat