2 problems with 2006 Mazda5. Dead battery and now like it's floored when starting

rkhanso

Member
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2006 Mazda5
We've had dead battery problems the past couple months. The battery is not that old (Jan 2010), but it's been dead often for my wife. A quick charge of the battery gets it going again for a week or more and then it's dead again. She said sometimes when she's shut it off, the blue high-beam indicator stays lit, even though the car is turned off. She said the headlights are not actually on. I've never seen this happen.

Then today, it wouldn't start for her, so I put the battery charger on it again (it has a super-duper start the car feature on it) and tried to start it. It started right up, but it immediately revs way up like I have it floored, though my foot is not on the pedal. I remember reading somewhere that this car doesn't have a throttle cable, but it's a motor or something that actually operates the throttle?

Right now, I'm cleaning the battery terminals (again) and have them disconnected for 1/2 hour or so to 'reset' the computer?

Every time I start it now, it iimmediately revs way up and I'm not sure what to do.(boom06)
 
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It seems to be working again.
I left the battery disconnected for 1/2 hour or so, cleaned the battery posts and clamps (the positive had some caked-on crud that I scraped off) and charged the battery. It starts and idles normal again. Hopefully that was all it takes to fix the problem.
 
Sounds like a strange problem - looks like you were able to reset your ECU and things are back to normal.

However, it looks like your charging system is going since the battery keeps draining - have you had the battery tested?
 
The battery is still dead occasionally. It seems to be when the car sits over a day or maybe 2 without being driven. Could there be a drain on the battery? How would I check for that?

I think I'll have the local Interstate battery retailer test the battery.

Any other things I can check?
 
My 2 cents,

Unlike in my old car where there is a voltage regulator inside the Alternator itself, in my 2006GT MAZDA5 the 'generator field current' is controlled by the Computer. Depending on reading from various sensors (head lights turned on, AC turned on etc).. the computer calculates and adjusts the 'field current' to the generator to maintain proper generator output..

Ways that the battery can drain that I can think of:
-- There is something draining the battery when car is off. (dealer should be able to check current leakage)
-- The battery is bad,
-- The car's system is not charging enough
-- Or battery is not receiving the charge (you did mention corroded terminal).

The charging system of the MAZDA5 is monitored by the computer and there will be CEL codes
like 'Charging system voltage low' Or Charging system voltage high'. If you don't have a CEL code then
it can be just a battery drain. or the battery not receiving enough charge (you did mention a corroded terminal).
Or the battery not accepting the charge (defective battery).
 
I went out today and checked the voltage before starting the car. It was at 11.79v.
Started the car and it's charging at 14.2v across the battery posts (not the connections/wires).
After shutting the car off, I checked the voltage and it was at 12.4v and dropping.

I took the positive connection off and checked the current draw with the car off.....and I think there's a problem. It fluctuated a bit when I first connected it (saw a little spark, too) and it settled around .43-.45 A. I'm guessing that's the problem. Doesn't that look like something is draining the battery when the car is off?

If there is a drain on the battery, what would be the best way to troubleshoot it? Would it be to remove each fuse, one at a time until the current drain is gone (monitoring the Amp discharge at the battery)? And, what if taking all the fuses out doesn't change the current draw?

Wouldn't all, or at least most of the items protected by fuses have no power when the key is not on run or accessory? Could it be a bad ignition switch?
 
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What you have to do is leave your reader connected for at least 30-45 mins to get an accurate reading after shutting down the engine. The draw you are reading is within normal specs because the ECM or some other module has not gone to sleep. Almost all vehicles ECMs or modules remain active for a specified amount of time (usually 30-45 mins). The problem with letting it sit for this time and then connecting your reader is that you will wake up the module the minute you touch the terminals with your reader. That's why you have to keep it connected and read the draw after 45mins to get an accurate reading. Hopefully our reader remains on and doesn't auto shut off because that will just void the entire process.
 
Thanks for the info.

I did take it to the Interstate battery dealer and they tested the battery. It read only 323 CCA and it's supposed to be 600 CCA. They replaced it for free (plus a $10 installation charge). Hopefully that takes care of it. Time will tell.
 
I'm still having the dead battery problem after the car sits for an entire day or two.

I measured the current over time today.
It started out at discharging at about .44A. After about 10 minutes or so (ballpark guess), it went down to .33A - and that's the lowest it went after about 45 minutes.

Now, I guess I have to remove the fuses 1 by 1 to see what makes the current drop to zero? Or what drops it the most?

I'll report back after that.
 
The fuse that took the amperage down to 0A or, 0.02A was the 15A 'Room' fuse.

That fuse runs at least the interior lights (dome, rear hatch and front dome by mirrors) because when I put it back in, the lights came on for about 10-15 seconds and went out. After I put the fuse back in, the amperage went back up to just under 1A and then back down to .44A after the interior dome lights went out.

I checked to make sure back hatch lamp is off, and it is. Not sure what's drawing current in that circuit, but I'll have to try to find a schematic and see if I can figure it out. Maybe it's running more than just the dome lights - which all do go completely out after the timeout.

The car did this when we bought it, but I didn't realize it was a battery drain - just thought it might have been a weak battery.
After we bought it, I did put in LED lights in the dome lights and the rear hatch....but as I mentioned, the car drained the battery before the bulbs were changed.

Any help/opinions are appreciated.
 
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I called the dealer and they said they'd have to go through the circuits on the room fuse 1 x 1 until they find out where the draw is coming from.
This can cost $$ if it takes them a long time.

I can do the same if I can get a schematic telling me what all the circuits are.

Anyone know of all the circuits/things that run off the "Room" fuse? Schematic?
 
I called the dealer and they said they'd have to go through the circuits on the room fuse 1 x 1 until they find out where the draw is coming from.
This can cost $$ if it takes them a long time.

I can do the same if I can get a schematic telling me what all the circuits are.

Anyone know of all the circuits/things that run off the "Room" fuse? Schematic?

Did you check out the schematics in the workshop manual that FLCRUISING posted in the previous message?

Also, are there any items that you added to the car that were not stock?
 
The fuse that took the amperage down to 0A or, 0.02A was the 15A 'Room' fuse.

That fuse runs at least the interior lights (dome, rear hatch and front dome by mirrors) because when I put it back in, the lights came on for about 10-15 seconds and went out. After I put the fuse back in, the amperage went back up to just under 1A and then back down to .44A after the interior dome lights went out.

I checked to make sure back hatch lamp is off, and it is. Not sure what's drawing current in that circuit, but I'll have to try to find a schematic and see if I can figure it out. Maybe it's running more than just the dome lights - which all do go completely out after the timeout.

The car did this when we bought it, but I didn't realize it was a battery drain - just thought it might have been a weak battery.
After we bought it, I did put in LED lights in the dome lights and the rear hatch....but as I mentioned, the car drained the battery before the bulbs were changed.

Any help/opinions are appreciated.

Do you have anything plugged into the 12vdc power outlet in the rear hatch area? I've had an 06, 08 and now a 10 model and noticed if I had something plugged into that outlet that sometimes the BCM would keep it powered even after the key was off. I had a few days a dead batteries until I unplugged it and the problem went away.
 
I had a hard time finding circuits on the schematics/manuals that FLCRUISING gave the link to. What I did was search all the .pdfs for the word "ROOM" thinking that I'd find all the circuits going through the "ROOM" fuse. But, it wasn't that obvious to me. I didn't see what I consider a traditional schematic, but more like block diagrams of how certain systems of the car operate.

It shows the BCM and all the items connected to it (lights, switches) but doesn't show if there are any other branches off of the room fuse. The only things I could see off of the Room fuse are the BCM and the PCM. Hopefully this doesn't mean I need the BCM replaced - especially without doing all the testing I can first (replacing a $350 part without knowing for sure it's the problem is hard for me to do).

According to the diagrams, it doesn't appear that there are fuses between the BCM and all the lighting in the car. I guess the only think I may be able to try is to remove the bulbs for the cargo, map and interior lights and see if that makes any change - though I doubt it will because none of the lights stay on, yet after a couple days the battery still goes dead. Unless one of the switches is making the BCM think it needs to stay awake.

I do not have anything plugged into either of the power ports in the car.
 
I had a hard time finding circuits on the schematics/manuals that FLCRUISING gave the link to. What I did was search all the .pdfs for the word "ROOM" thinking that I'd find all the circuits going through the "ROOM" fuse. But, it wasn't that obvious to me. I didn't see what I consider a traditional schematic, but more like block diagrams of how certain systems of the car operate.

It shows the BCM and all the items connected to it (lights, switches) but doesn't show if there are any other branches off of the room fuse. The only things I could see off of the Room fuse are the BCM and the PCM. Hopefully this doesn't mean I need the BCM replaced - especially without doing all the testing I can first (replacing a $350 part without knowing for sure it's the problem is hard for me to do).

According to the diagrams, it doesn't appear that there are fuses between the BCM and all the lighting in the car. I guess the only think I may be able to try is to remove the bulbs for the cargo, map and interior lights and see if that makes any change - though I doubt it will because none of the lights stay on, yet after a couple days the battery still goes dead. Unless one of the switches is making the BCM think it needs to stay awake.

I do not have anything plugged into either of the power ports in the car.

For further clarification: Is there anything aftermarket on your car? (Stereo, amplifier, headrest monitors, DVD, homelink mirror, etc...)
I will look in my manual at the wiring diagram and see what is on the ROOM circuit, and report back...
 
I bought the car used, and did not add anything aftermarket. Do not see anything else aftermarket.
 
One way is to put a multi-meter on a high current range [say 5 amps or lower if you think the errant current is under a known value] and connect it temporarily between the +ve batt terminal and the +ve cable. The only things which run all the time are the clock [if fitted] and perhaps any anti-theft device(s) All these should not exceed much more than 0.1A or close.

You then watch the current range reading while removing fuses. If all fuses dont cause a change, then there is something running non-fused, which could include the alternator. In that case, un-doing the alt connections should remove the drain and point to the alt. If nogo,..try disconnecting connections and even removing relays.

JJ
 
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