Or if the battery is dying - in which case the charging system even if 100% OK cannot overcome the battery's state. You need a really good test to check a battery is fit for a modern car's electronics.

 

Get a hygrometer and check each cell of the battery, there could be a weak one that a voltage check may (or may not) find. This way is the best way to check a battery...
Good luck.

 

It is hard to truly test your battery accurately at home. With today’s technology all you need to do is take it to AutoZone, Sears, PepBoys or whatever and have them give it a test. They have the equipment to test it properly leaving out the guess work.

 

Gus - I think we've seen several people who've done that and the battery was deemed OK, but it wasn't and after further grief they've replaced it with finally a cure for their problems.

 

You are correct!

 

i will buy a new battery this weekend.. any suggestions?? i cant seem to find an Optima Battery that will fit my STR..

 

I hope you are getting the battery because you need it and not because we are suggesting you get a new one. If it tested bad you are doing the right thing.

 

well it tested "Good Battery" at AutoZone so i guess im not doing the right thing??

i ran a quick test with my neighbors multimeter.
DCV20 with the car off. 12.41
DCV20 with the car on. 14.41

are these #'s those of a bad battery??

 

Good meaning what? It is holding the voltage required or is it satisfactory. It seems that satisfactory is nor suitable for these cars. Do you know how old the battery is? If all is good clear your codes and see if you still have the problem.

 

Wait. That 14.41 volts seems a little bit high with the car running. Almost like the voltage regulator in the alternator isn't working right. Typically you see something around 13.8v with the car running.

Does anyone else agree with me on that?

Take care,

George

 

Thanks George, I thought it was high and was looking for supporting information but was unable to find it. I had not had reason to dabble with the voltage output from the alt.

 

Depends how cold it is, so-to-speak....

 

If we determine that the battery is good then I would suggest checking the TB plug for a clean and tight connection.

 

14.4V is NOT high. It's the way these cars work when initially recharging. All in JTIS.

The voltage you need is the LOWEST during CRANKING. That's what the modules suffer. You need to measure any voltage spikes/drops even of SHORT duration, say 1ms. You'll need a specialist meter or DSO.

Do it when the car's been sat a while - overnight at least - so you get the WORST reading.

If you don't have the tool, you need a thorough and 100% reliable battery test or a Plan B. Like buying a battery. Most everything costs more.