No crank no start

[Yeagerbombs7]

I recently drove my car home and the ride was fine. The next day I have a no crank and no start. From the reading I've done it could be a number of things. I've replaced the start, no help. I've never looked for/ corrected bad grounds. Can someone help me rule this out or identify another cause? I've read a thread about a bad pcm, hoping that's not the case.

 

[dark steed]

Search “no crank no start” and there are at least 10 threads. Read through those and see if anything matches your conditions.
This platform is getting close to 20 years old, it has happened to numerous individuals before.
Also this probably doesn’t fall under “Tech” so don’t be miffed if it gets moved…


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[Robert Larimer]

I think the most common no crank failure is the battery. If it is at all weak the voltage drops too much and the ECU goes crazy. The days of slow cranking due to battery failure are gone. Modern cars will not even try to crank if the battery is low.

 

[Iceman62]

^^Yep^^

Meter the battery - what's it look like...how old is it?

I drove to work one day w/ my truck & it started fine...went out to go home = boom/dead battery.

 

[Pentalab]

With eng OFF, put a dvm across the battery terminals...should be aprx 12.5 vdc. With eng on, and idling, it should read 14.75 vdc.

IF it reads 12.2 to 12.5 vdc with eng OFF, leaves the dvm across the batter terminals...while a helper try's to start the eng. If the DVM vdc drops like a rock, like < 11 vdc, or even lower, the battery is toast..and won't deliver any current.

IF it starts fine...and while idling..and battery reads 12.2 to 12.5 vdc the alternator is DOA.

 

[Derf08]

There is an alarm module under the passenger side dash. You need to remove the glove box and it should be parked above and just to the left of the blower box. That module can go out over time. The dealer can simply bypass the starter circuit without changing the operation of the system. Or, if you're really good with electrical schematics you can do it yourself.

Easy way to check if it's bad is to remove its cover and check the fuses inside. As I recall there is a 5amp and a 15 amp. If one or both are blown it is definitely toast.

It looks identical to this with two wire harnesses plugged in. Some have a pinout on the back, most do not.
https://www.ebay.com/itm/2852118852...MI2rjN0O3I_gIVlRjnCh1JTwssEAkYASABEgIh7vD_BwE

The hard way is to bypass it and test the rest of the starter circuit. I say it's hard but, only because if you've never done it, it can be tedious.
Here are the instructions I created under Post #2 of this thread
https://mustangforums.com/forum/2005-2014-mustangs/744858-no-crank-anti-theft-issue.html