Today my wife came home and said CEL was on, so I connected a bluetooth OBD2 reader (like I have done before) and read the codes, a P144a, which has something to do with the EVP. So, I shut the key off and proceeded to take the hose off of the EVP and unhook the wiring connector and then start the car to see if there was a vacuum leak through the valve. Well, when I went to start the car, it would not start. The Securilock icon was flashing on the dash and the car would only click, it would not turn over. I tried our spare key and got the same results. I have tried unhooking the battery for 30 minutes but that has not made a difference either. Now, the key fob won't work at all, the door power locks won't work, the windows don't work, the radio, lights, heat and A/C won't work, and the dome lights won't come on. Whenever the battery is connected, I can hear a fast clicking sound coming from the area beneath and behind the radio and the front marker lights are on very very dim. The battery tests out at 12 volts. What in the world did I do and how can I fix it?

***edit: I should also note that I cannot get my OBD2 reader to connect to the system anymore. Also, after trying to leave the battery unhooked for 30 minutes again, the dome lights started working and the power locks would lock the door, but within about 3 seconds, the doors would automatically unlock. After turning the key to the start position, I again lost the dome lights and power locks.

 

Measure the battery voltage WITH THE KEY TURNED ON. Measure at the battery posts and also measure on the cable ends themselves. 12v from the battery with the key off and/or the cables off the battery doesn't tell you anything. I bet the battery is low or you have a bad connection at the battery.

 

I agree. "12 volts" doesn't mean much, the decimal point matters when it applies to a battery! A full charge on a maintenance type battery is 12.65 volts, 12.0 and it might not turn over, etc.

Can try charging but sounds like it's down swapping electrons. Best to remove it and have it tested, or if several years old replace.

 

The battery voltage does drop significantly with the key on, down to almost 8 volts, but why would the PATS system not allow me to even try and crank the engine? It is almost like the PATS system is disabling everything when I turn the key to the on position.

With a charger on the battery, and the key in the acc position, the radio and accessories will work. Also, with the key off and charger on, the key fob will also work. When I turn the key to the on position, the PATS will disable everything.

OK...so I have been trying different things as I write this reply. After having the charger on for a while, everything seems to function like normal when I turn the key to the on position, the PATS system disarms itself like it should. I have not yet tried cranking the engine. I will let the charger run for a while first, as I don't have a "crank" function.

If this turns out to be just a dead battery I am going to feel pretty stupid.


Thanks for the suggestions.

 

You still want to have the battery load tested or conductance tested. The idea is to keep the alternator and charging system happy.

 

The battery was over 7 years old, so I went ahead and just got a new battery. Installed it and everything seems to be working okay now. Voltage only drops a tenth or two when the key is turned on. That was definitely a bad coincidence to have the battery finally die after reading the diagnostic codes. It seemed weird at the time, with the clicking noise, but now it kind of makes sense. Those modules (and other components) require a certain voltage to operate, and with the bad battery, the voltage would drop low enough that everything would shut off, but as soon as it shut off, the voltage would recover and the modules would turn back on, and so the cycle continued, causing the constant clicking noise.

Lesson of the day...don't look over the obvious things that should be checked with any electrical issue...aka the battery.

Thanks for the help.

 

If the battery was run down but good, the same thing could have happened. When the battery runs down, they consider it like a resistance inside the battery, just like a bad connection can be a resistance. I will give you my "garden hose" example;

Think if the battery and the large wires coming from the battery like a garden hose in your yard. The voltage is the water pressure. The current is the waterflow. You need both to do anything(turn the engine over).

Your problem was just like having a kink in the water hose. With the kink in the hose, you will have water pressure at the nozzle, if you are not using it. If you let just a trickle of water out of the hose you will still have pressure. But when you open the nozzle wide open on the hose with the kink still in it, the water will give a little squirt and then fizzle out.

This is exactly what happens with a low battery or a bad connection. The very small resistance in the dead battery or the cables is the kink. The resistance will let enough current flow through to run the radio, domelight, and other small loads like your voltmeter. But when you try to start the engine, the starter draws ALOT of current. This is like opening nozzle on the water hose wide open, and you lose everything. Let off the starter, and everything comes back, just like the kinked water hose, as the flow stops enough water goes through the kink to build the pressure back up.