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2003 Acura MDX - Battery Discharges and Vehicle Will Not Start

Hi All,

I am writing with the hope that someone can help us.

We live in Minneapolis, MN. We have a 2003 Acura MDX with over 100,000 miles. It has been a great SUV, until recently. This fall we had all the required 100,000 mile maintenance work done, including replacing the timing belt, etc. About a week later, the battery drained and the car wouldn’t start, and at the same time the starter went bad (noise, smoking). We had the starter replaced and a new battery installed. Car still would be dead each morning. We took it back to the shop that had done the maintenance (4 different times) and they couldn’t find the problem, so they finally just replaced the new battery with another one. Same problem.

Then we then took it to the Acura dealer where we bought it. They ran diagnostics, kept it for three weeks, and couldn’t find the problem. It started almost all the time for them. One day we went to pick it up and it didn’t start, so they kept it another week. They had it outside most of the time, so it’s not the cold as we thought it may be. Today they threw up their hands and replaced the battery (third one). We have tried not locking it, thinking it could be the security system, turning the radio off, the fan off, etc., but nothing works.

This is a good vehicle and we planned on having it many more years, but it’s worthless if we have to jump it every other day.

Does anyone have any ideas?


We are on battery #3 so even the Acura tech says it is a battery issue. U need to find which circuit is the problem. Or find a shop that does auto electric repair

Thank you. The Acura Dealer has been trying to find the circuit that is the problem, or “parasitic drain” as it has been referred to. But they can’t find it despite weeks of trying. The issue is that it doesn’t drain all the time. Usually, if we jump the car in the morning it will start again during the day. But it does not start in the morning after being in the garage all night, or after sitting for more than 8 hours. The Acura Dealer said an auto electric repair shop would do the same things the dealer is doing.

First, You need to know if they tested for a drain in the electrical system and if they load tested the alternator, There is a thing called a load drop test that I would make at this point. Also make sure the alternator belt is tight.

Back when I was a mechanic, I had a car where (After doing the above prerequisite tests), I replaced the battery. About a month later it came back needing yet another new battery!

What I missed as it turned out, was that the alternator was overcharging the system. The reading was stuck at 14 volts. The next morning it was working fine again.
one symptom I have learned to ask the customer about is if they ever smell rotten eggs while driving the car. (an overcharging alternator and a clogged Catalytic converter are the only things I have witnessed that can cause such a thing).
In this case I had to replace the alternator. (Which I did charge the customer for).
and I had to put in yet another new battery (Which I had to eat).

You’ll have to narrow it down to a circuit and that will require a bit of investigation.
Try this:

Pull half the fuses and let it sit overnight. In the morning, see if it retained its charge, helping you decide A or B:
A - If it didn’t hold its charge, pull half of the remaining fuses and see if it holds a charge overnight. If it doesn’t, pull half of the remaining fuses, etc (basically recursing through A and B).
B - If it did hold a charge, put 1/2 of the pulled fuses back in and see if it retains its charge, etc. (again, doing the A/B recursion some more).

Eventually you will have narrowed it down to one fuse that indicates the circuit that draws the current. Then see what’s wrong with that circuit. If you are unable to find anything wrong with that circuit, at least you’ll know what is draining your battery and can tell whomever will work on your car about it.

In lieu of that, you could buy one of these gadgets and see where the current goes: One of the circuits is bound to draw a significant amount more current than any other.

The parasitic current draw might be caused from a module that’s failing to go to sleep. If this is the case, the battery cannot be disconnected when checking for the current draw. Because if there’s a module that is failing to go to sleep and the battery is disconnected it forces the offending module to go to sleep. So then when you go and check for the current draw it’s not there.

Call the dealer and ask them what method was used to locate the parasitic current draw. And if they tell you that they disconnected the battery, that’s where they made the mistake.


Each night, open the fuse box and pull one or more fuses overnight. If the problem still happens, then you can rule out those circuits. You might be able to narrow it down to a specific circuit this way.

By the way, I should point out that you got a bit lucky with your timing belt. It was two years overdue. Had it broken, you’d be paying around $4,000 to replace or repair your engine.

My dad had a similar problem on a 1973 Oldsmobile Cutlass S that he owned. He bought the car used and the car had a “reputation” for this problem. If the car sat for more than 2 days, the battery was too low to crank the engine. His mechanic replaced the battery which didn’t solve the problem. He took the car to an electrical shop. The technicians all disappeared into either empty oil drums or the restroom when the car came in. The proprietor admitted that they had seen the car several times for that problem. At any rate, they didn’t find the problem.
I decided one evening to try lion9car’s method of pulling fuses, but first I disconnected the negative battery cable and then scratched the clamp against the post. I got a spark which indicated a current draw. I reconnected the cable and got under the dashboard to begin removing fuses. I thought I would pull the fuses until I could disconnect the battery cable and then not get a spark when I would scratch it against the post. Before I pulled the first fuse, I happened to glance back toward the seat and saw a bead of light around the lid of the console. What I found was that sometimes the switch would stick for the light inside the console compartment. I removed the bulb and repeated the test looking for a spark at the battery. There wasn’t a spark–the sticking switch was the problem. My suggestion is to look around when it is dark for light that may be sticking on. You may even want to remove the light in the glove compartment or other places.
I am pretty simple and not much of a mechanic, but I always look for simple things first. 90% of the time, I find the problem.

Thank you all very much for these suggestions. We will ask the service manager at the Acura dealer the questions you stated and will also try the other ideas ourselves. We will let you know what, if anything, works!

Something overlooked here, is there any electrical circuit that is NOT working, i.e a power window or power door lock, or is not working as it should. If so, that would be the starting point. You cannot assume that because a circuit is not working, that it is not drawing any juice.

Dealer cannot find problem. So they say any other shop will also not be able to find problem? Something is draining new battery in 8 hrs? U need an infrared camera. Put car in cold garage or outside, it is mpls after all and scope out car. Maybe it is the power seat module? Or try and touch different modules under hood and see if any are warm

“The Acura Dealer said an auto electric repair shop would do the same things the dealer is doing.”

I disagree. An auto electric repair shop will use a multimeter to isolate the ciruit that is the parasite and troubleshoot that circuit to determine what exactly is gobbling the juice. It’s a matter of tracing back through the circuit. I’ll post a circuit schematic just to illustrate the idea.

Also, a repair shop might have access to a trouubleshooting protocol such as the one I’ve attached

Frankly, the dealer has access to the necessary information too, but apparently can’t be bothered.

One simple thing you can do is upkk the fuses for all the nonessential circuits and see if the problem goes away. If it does, replace the fuses one by one, and when the problem reappears you’ll know which circuit is the problem. If removing those nonessential fuses doesn;t help, you’ll at least have eliminated them as possibilities. Frankly, the dealer could have done the same basic thing with a multimeter (measure current flow and remove fuses to isolate the problem).

Now I’m going to take a wild, unsupported, off-the-wall guess. I’ll guess that you have a high resistance short to ground in one of the wires that goes to the door locks. Those are always “hot”, and the wires can abrade and short to ground where they flex whenever you open and close the door. Always-hot wires are liekly to be the ones draing the battery.