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Can my amp setup damage the PCM?

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Location
Cleveland
#1
Recently I had to take my car to the dealership because my 16 fiesta would randomly die on the road. All the lights on the dash would come on, and i'd lose power and steering etc, and then I would have issues restarting. Pulled code with Forscan lite and basically got a bunch of comm errors for various modules. The dealer said that since I have my amp drawing power directly from the positive terminal of the battery, then it was bypassing the BMS and caused damage to the PCM. So they replaced the PCM under warranty,(good thing I didn't underestimate the stigma of Found On Road Dead and got extended/premium warranty, can't remember which), and wrote some note regarding aftermarket amp hookup causing issues.

Got my car back for 2 days now, and it's been working okay, but I really miss my bass >_< I've had my setup since Feb 2018, and had this same issue in August, brought it in, they reset some stuff and was good until recently it happened again, so I want to think that the amp didn't really cause any damage. Do you guys think the dealer was just pointing out the first possible issue? or do they have a valid point? if so, what alternatives do I have for power source?

Another issue, they were saying about my setup was that it was causing a lot of RF interference and caused them issues when programming the keys to the new PCM. They didn't say if the interference only affected the programming of the keys, or if it's bad enough to cause issues for daily operation.


Also, I have already changed my battery, the quick and dirty solution that everyone recommends when there's electrical issue.
 


Intuit

3000 Post Club
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Location
South West Ohio
#2
May be standard practice that any condition (such as cracked windshield) that is deviant from stock is mentioned. It provides an optional "out" later if the vehicle just keeps being brought back, over and over and over.

Does the amp have some sort of remote-control capability? Unless it does, I suspect it's safe to call BS on that part. Do you have a shot of the invoice containing the language used?

Whether the power draw is truly related, can't really say since we don't know anything about the setup. Do you have a switch wired in-line with the amp's remote turn-on?

Weird things do happen when power is running short. Even though there's a cable running directly to the battery positive, there isn't one running to the battery negative; which means all electronics must compete for that small (but short) cable. It is possible to reinforce the existing negative with an additional low gauge, short run to the body/frame. (paint must be stripped so have to choose the location wisely)
 


OP
ryuken2k5
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Location
Cleveland
Thread Starter #3
That's what I'm thinking too. Before I took it to the dealer, I've found posts on here for the same issue, and they were dealing with bad fuse or just like in my case a bad PCM but no reason for the cause.

No switch for the remote, just a fuse tap to the moonroof fuse.

And I think it might be a ground issue, but I don't know how to test with a multi meter. I grounded to near the right corner of the trunk, right under where the carpet can be lifted up. And I know, shitty Boss amp but it got the job done(willing to replace if it is indeed causing problems). Also bad cable management but bad enough to cause a problem? Odd thing i noticed is that, there is corrosion(galvanic) on the power cable to the amp so maybe this is the issue?



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Messages
161
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160
Location
Charlotte, NC
#4
I agree that it sounds like standard practice to mention anything aftermarket that could be related to a failed component.

As far as the amplifier goes, the ground looks good but it may be worth it to remove the cable and sand down a little extra to make sure there is plenty of bare metal for the wire to connect to.
I believe your amp is a Class A/B as well, which typically is less efficient than a Class D. If I remember correctly, a Class A/B amp will use more power for the same sound volume than a Class D. I'm wondering if maybe it's just continuously drawing more current than the alternator can put back in the battery, leading to a situation where the battery is short of voltage going down the road. Although, at 1100 watts I doubt this is the case. Maybe just something to test if you happen to have a smaller amp lying around that puts out less wattage.
 


Intuit

3000 Post Club
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#5
I meant improve the ground between the vehicle and battery. But the ground between amp and body looks to be insufficient also.

Here's the deal though. If it happens again, regardless of whether the equipment is at fault or not, it's going to get blamed. A repair like that is probably going to cost over $1,200. I can see the service tech cursing up a storm based on what I read there. They only have so much time on the book for diag and repair, and that undoubtedly went beyond the time that Ford allotted for the repair. It's a time killer... "murdera".

To be on the safe side, I would keep it totally disconnected for the time being. Was the audio system running exceptionally loud at the time that the issues occurred? They way they typed it up, it seems to point directly at it. But what you tell them and what ends up on paper can be totally different. Brother has an amp that IIRC pulls 1,000 watt RMS (not peak) and could knock the RPMs down when the bass hits.
 


OP
ryuken2k5
Messages
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Location
Cleveland
Thread Starter #6
Yea, the tech was nice enough to still get this covered under warranty but probably not going to happen again.

Right now, it is disconnected, but I miss having bass, the stock sound is really lacking in the low end :/

As for the 1100 Watt rating, that's a cheap Boss amp, so that rating is highly overrated according what people say online. I haven't noticed my RPM go down when the bass starts hitting hard.

This is the amp i have now is BOSS Audio R1100M
https://smile.amazon.com/gp/product/B004S4XNEO/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

The sub is Pioneer TS-SWX2502
https://smile.amazon.com/gp/product/B00JQTU3QC/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

If the amp could be part of the issue, I might upgrade to Rockford Fosgate R500X1D Prime, Class D, more efficient right?
https://smile.amazon.com/gp/product...c_title_dp_1?ie=UTF8&psc=1&smid=ATVPDKIKX0DER


Lastly, grounding, where else is a good grounding point for the amp? I've read that people use the seat bolt, but when I first tried that, I couldn't get the bolt to fit through the ring terminal I had so I picked somewhere else. What size would I need if I decide to ground here? Also, I've already sanded down the contact point between the negative battery terminal cable and the chassis, but I'm not sure what else I can do to improve grounding.
 


Messages
65
Likes
14
Location
Sacramento
#7
I just bought this Power Acoustik Razor amp at Walmart, so small i have it velcro'd in place, works really well and doesn't get hot at all, barely warm in fact even after an hour of driving around bumping deutschrap [emoji38]


Sent from my SM-J727T using Tapatalk
 




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