car battery dead, power steering comes and goes.
October 13, 2021 3:34 PM   Subscribe

So my car battery died for the second time in a week, and there's an odd whirring noise. Strange issue with power steering.

2014 Mazda 5, automatic transmission.
A week ago, car battery was dead, car would not start. Called assistance, guy came to jump start it, before he did we noticed a strange 'whirring' noise in the engine, like a small electric motor.
Car started, worked OK. The whirring sound was gone.
However, the power steering was wonky: it felt like it was turning on and off randomly while pulling in and out of parking. No issues while actually driving.
This comes and goes: sometimes it works fine, sometimes it doesn't, sometimes it shuts on and off while parking.
I went away for a few days, the battery's dead again, and the strange whirring sound is back.

QUESTION: does this sound like just a bad battery or is there a deeper issue? Should I just buy a new battery and see what happens or do I take it a more general workshop, or one that specializes in electric systems?
posted by signal to Travel & Transportation (13 answers total)
Dead battery implies problem with alternator. The alternator, power steering pump and other accessories are usually driven by a belt, often called a serpentine belt.

Squealing can be a symptom of a belt slipping, either due to wear or something preventing the belt from driving everything smoothly. If these issues are related, it's probably due to a belt slipping or some pulley problem preventing the alternator and the PS pump from being driven correctly.

Another common issue causing squealing is a problem with the PS pump, often occuring when PS fluid is low.

I would recommend turning the car on with the hood open to see if everything looks like it's moving okay. I would also check the level of PS fluid.

There's often a voltage meter or idiot light to show if the alternator is functioning. Check if the light is on or if the voltage meter is indicating a problem. You could also get the charging system tested at an auto parts store. They often have a gadget that tests the battery under load and how well the charging system is working.

Good Luck!
posted by jclarkin at 4:02 PM on October 13 [2 favorites]

The battery could just be dead but that can be tested fairly easily. I misread and though this was a new battery. Auto parts store testing should rule this out. But if the battery is several years old, I would guess it could be worn out.
posted by jclarkin at 4:04 PM on October 13

A quick google makes it appear that this car uses an electric power steering pump. (It's an electric pump that generates hydraulic pressure to drive the steering rack rather than full electric power steering.) It sounds like whatever module or relay controls the power steering pump is getting flaky and possibly keeping it on when it shouldn't be and killing the battery. (My theory is that the whirring noise you're hearing is the PS motor) It's also possible that a marginal battery is creating a low voltage situation and that's why the controller is freaking out. It really could be either way. My money's on a bad control module, but a battery is cheap and easy to change.
posted by Larry David Syndrome at 4:06 PM on October 13 [2 favorites]

When you disconnect a healthy battery, does the whir go away?

Sympathizing, I miss my Mazda 5.
posted by nickggully at 4:44 PM on October 13

Checking 2014 Mazda 5 Power Steering pump shows that this is an electrical pump, not the engine driven kind (there is no belt pulley on it) . So if that pump is intermittent it can be sucking your battery dry.

Keep in mind that a drained auto battery probably loses capacity from being drained. May want to find a reputable shop with a battery tester to make sure it's usable.
posted by kschang at 4:55 PM on October 13

Response by poster: Thanks all. I don't know anything about car mechanics, so I won't be testing anything myself. I have a friendly small shop that sells batteries nearby and another more complete one that does car electronics and is farther away. Basically trying to figure out if its worth it to go to the first one or just skip it and go the farther away more specialized one.
posted by signal at 5:23 PM on October 13

How old is the battery? I had a 2010 Mazda3 and the battery life was ~5 years, so if it's an old battery I'd start with replacing that and see if the other problems go away or not.
posted by DoubleLune at 5:39 PM on October 13

My 2009 Corolla and I had a very similar experience to yours a few months ago: intermittent steering issues while parking, whirring sounds, battery failure.

My automotive knowledge is pretty sparse and old school, so I had no idea electronic power steering was even a thing. It all made sense once I found out that bit of info.
waning battery => electric thing behaves badly

I did some reading and poking around (because PRIDE) before calling my retired-mechanic dad who agreed with my hypothesis. I charged the battery and did some voltage tests under load, etc that he suggested, confirming that it was at the end of it's lifespan. Replaced the battery; no problems since.

There should be a date on your current battery, and yeah, they want replacing every 5 or so years. I picked one up at costco and swapped them out. It's definitely something you can easily do yourself if you have the desire. If not, just go to the local shop. If problems continue, you can always go to the specialist, but I suspect a new battery will do the trick.
posted by bethnull at 6:47 PM on October 13

Last year, my 2015 Toyota Camry (with its original battery) started having weird steering/pulling issues when pulling out of my parking spot. It seemed kind of random. It happened maybe 3 or 4 times over a week or so. I would turn it off, turn it back on and it would be fine. Then the battery died in the parking lot at work. I replaced the battery and i haven’t had the same problem since. I spent some time internet searching to see if they were related and i remember reading some things about how that’s one of the signs the battery is on its way out. I would start with the battery and see if that fixes the problem.
posted by August Fury at 6:47 PM on October 13

It sounds like it could be the power steering is bad and discharging the battery or the battery isn't holding a charge or getting charged properly (alternator) and isn't able to supply enough power to the power steering pump. Either is possible.

The reason you have problems parking is this is when the greatest load is placed on the power steering (you're turning hard and barely moving). It could also be that the alternator isn't able to produce enough power with the motor at idle to power the pump.

If you charge up the battery overnight and then try your normal parking maneuvers for a while, that should tell you if the problem is the power steering itself (if it keeps happening) or the battery or alternator (if the problem doesn't occur with a fully charged battery). Or just bring it to a shop, have them test the battery and alternator and go from there.
posted by ssg at 7:02 PM on October 13

Response by poster: I got a jump-start, drove to the shop. They measured the battery, said it was dead and that this was consistent with the power steering problem. Sold me a new one, car starts now. Fingers crossed that that was it.
posted by signal at 8:45 AM on October 14

Response by poster: Oh, they also measured the alternator with the new battery and said it was charging OK.
posted by signal at 8:45 AM on October 14

I'd bet it was the battery.

I've had batteries die on me after less than 3 years. Cold weather, long periods of sitting idle (pandemic, anyone?) can do a number on the battery.

If the new one dies, then you have an alternator issue. But you'll likely be fine.
posted by vitout at 11:39 AM on October 14

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