so hopped in my car this morning and when i turned the power on the tac needle slowly went all the way up and dropped back down, the odometer read all dashes no numbers, and the theft light was flashing brightly.

the car wouldn't even slightly turn, and when i tried to read the DTC codes it said it was unable to read.

no idea whats going on, any suggestions to point me toward the cause would be awesome

 

thinking maybe a blown fuse? where do i start for that?

 

The battery may be going out. I've had the same thing happen to my 2002 F-150. It was the battery. If the battery posts are corroded, clean them up. Make sure the cables are tight also.

 

battery is a red top thats only about six months old. powers fine. it feels more like the computers not getting pwer and the fuel injectors aren't receiving the command to do their job.

 

PATS problem maybe. any quick fixes for that or am i headed to the dealer on a tow truck?

 

also i found under hood fuse 20 was blown, i replaced that and no change. and my trac control button light is on w/o pushing the button. when the the keys not even in it looks like the bat light and the air bag light is receiving power. but the light is very feint

 

Even though the battery is relatively new that doesn’t mean that it is good. You could have a parasitic battery drain that sucked it dry. Check the voltage. It should be between 12.4 & 12.8. Any lower then that and strange things can happen.

Also check all your ground cables & connections. Make sure they are all clean & tight.

Also check the power & grounds going to the computer before condemning it. If there is excessive resistance on the power or ground wires (yes, there are multiple for the computer) strange things will happen because it is not getting the voltage and current flow it requires to do its job. Good luck...

 

i'm 100% sure the battery is good, its usually a little high 13.5-14.5 during operation. and recently has been in the mid to high 15's during the initial start of the day. i haven't seen any corrosion on any of the power points.

thanks for the help i'll check out the grounds to the computer today

 

Sorry, but your not testing the battery when the car is running. Your testing the alternator. To test the battery the car can’t be running.

btw, over 15 volts while running is excessive indicating your alternator is working harder then it should because it is trying to charge the battery because its low or bad. This can quickly wear an alternator out.

 

Or your voltage regulator is borked.