Erratic Electronics

[Greg2013SHO]

Since my 2013 SHO issues have been somewhat clarified I’m trying this on a new thread.

There’s no problem with the alternator or the battery. The flashing panel lights that took out my information system has not reappeared. I made yesterday’s 4 hour drive with a stable situation: no radio/CD player, no bluetooth, no full navigation, none of the abilities accessed from the main display screen. But I maintained speedometer, odometer, A/C, turn signals, trip calculator, etc. I was able to get some navigation from the steering wheel buttons, displayed on the dashboard for guidance but of course no map. I had to live with that red star on the main display screen telling me how to restart the car.

Altho the indie shop didn’t mention it my buddy’s research found that such erratic electronics can be caused by loose fuses. One fellow was able to overcome his issue by reseating them. Then the computer was available for function re-set. Someone else reported that a battery that drops significantly below 12V can cause this problem.

I’d rather not have the local Ford dealer give me the same non-solution as the indie shop and charge me a diagnostic fee. Can any of you shed light on this? Thanks.

 

[SHOrod]

Weak batteries, even if the voltage seems good, can cause some pretty goofy issues. From my experience, it seems 3 years is about all the longer I can trust a battery in a newer vehicle. If your battery is at least 3 years old you may want to see if replacing it will remedy the issues. Even if it doesn't make a difference, it's not totally wasted money.

-Rod

 

[Greg2013SHO]

Thanks for that, SHOrod. Yes, the other suggested cause was a weak battery. My friend’s research found that even somewhat below 12V can cause erratic function. We put the trickle on my battery overnight after I arrived at his place. Could be that it overcame some threshold. The battery is relatively new, maybe 2 years. The indie shop thought it looked great. Checked out fine. But if the problem happens again I won’t top it off. Just take it to a shop for their analysis. It still raises the question of why they couldn’t reset the error and get me back to full function. Something was preventing that.

I thought I had once stumbled onto a battery charging read-out in my scrollable instrument panel group but can’t find it in the manual. All I see is a battery warning icon.

I’ll be taking it in to a Ford dealer to replace a broken side view mirror. Any advice I get here will be folded into that visit.

 

[SM105K]

@SHOrod is pretty much dead on with his post. Batteries in my SHO only last about two years. These cars have a high electrical demand and depending on your climate it really beats them up.

 

[Greg2013SHO]

@SHOrod is pretty much dead on with his post. Batteries in my SHO only last about two years. These cars have a high electrical demand and depending on your climate it really beats them up.

Which climates are the hardest on them? I keep the car in a garage in southern Louisiana. My northern drives are in the warmer months.

 

[luigisho]

Really hot, really cold. Very low temps are worse but really high is no bueno either. Not much you can do about it except keep an eye on it and know that these cars drain those suckers faster than you thought was normal. I get 3yrs average on my old 93 SHO and 14 F150. Many years ago that average was probably more like 5 yrs or more.

 

[Greg2013SHO]

Really hot, really cold. Very low temps are worse but really high is no bueno either. Not much you can do about it except keep an eye on it and know that these cars drain those suckers faster than you thought was normal. I get 3yrs average on my old 93 SHO and 14 F150. Many years ago that average was probably more like 5 yrs or more.

Thanks!

 

[SM105K]

Which climates are the hardest on them? I keep the car in a garage in southern Louisiana. My northern drives are in the warmer months.

Here in PHX we can see highs of 120* in the summer. Even in my Focus ST batteries seem to only last roughy 2 to 2.5 years as well.

 

[GHNorth]

Which climates are the hardest on them? I keep the car in a garage in southern Louisiana. My northern drives are in the warmer months.

If you keep it in a garage, you should hook up an electronic battery tender. I put mine on as soon as I park. My current AGM Diehard has been great for over three years. My prior AGM Diehard only lasted a couple years I think the AGM battery in my Torino is well over 10 years old.


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[Majestic]

Make sure to reset the BMS when you change the battery.

 

[SHOdded]

equip yourself with a solar ba9 or similar tester to verify battery and alternator. just checking voltage is not enough.

if both are good, check your OBD adapter. if you leave it plugged in all the time, this scenario can occur during startup. the solution is to plug the adapter in after startup or get a better adapter.

 

[Greg2013SHO]

Make sure to reset the BMS when you change the battery.

That tip is news to me, Majestic. I looked up BMS resetting online and found this:

It’s for a Ford Escape but covers the years of my 2013 SHO. 5 high beams and 3 brake pedals. Watch for the battery icon to flash three times.

I checked my battery’s age. The code says it’s 4.5 years old, installed 30K miles ago. Hopefully the dealer did the reset correctly. This car sits in my garage for long periods. I use it only for long drives and occasionally around town in really bad weather for safety or transporting friends in luxury. Can be quiet for a month or so. Recently I’ve applied trickle charges to play it safe. So no extreme high or low temps but the extended dormant periods must be stressing it. The advice I’m getting here is to replace it when I get to my destination.

Out of curiosity, can I reset the BMS on my 1989 SHO the same way? I replace those batteries myself. Mike from SHO Source guided me about not pumping the gas pedal too much since it would throw off the programming, esp idle speed. This is the vehicle that sat unused for years. Once I got fuel into the line I should disconnect the terminals to clear the buffer, reconnecting only after 10 mins. Then turn the key with no pumping. Let it idle for 3-5 mins. Should start right up and with the correct protocols. My idle settled into 1500 RPM. Is this the same as BMS setting in the older models?

Thanks to all.

 

[Majestic]

I doubt the 89 has BMS. I've never had luck resetting the BMS other than using Forscan.

 

[luigisho]

I doubt the 89 has BMS. I've never had luck resetting the BMS other than using Forscan.

89?

 

[Majestic]

89?

"Out of curiosity, can I reset the BMS on my 1989 SHO the same way?"

 

[luigisho]

That's what I get for skimming.

 

[Greg2013SHO]

Now that I’m in the family home I took the car to my trusted indie shop. Much more expertise than the place in Raleigh. There are 4 electronic modules that connect to a central one. From their names some of the functions seem to overlap but the mechanic said they perform diff functions. Right now my radio module is dead (non-communicative). He can replace that as a start. The others are TBD. Same problem with diagnosing issues unless there’s a clear failure. Some low voltage codes but until he begins swapping in good parts he can’t act upon those. His parts are from Ford. Then he can try resetting the computer. I’ll be here for a while so might have to drive it around to force clarity.

There are ball joints that are wearing out. Reasonable approaching 100K miles. He can do that too. The other shop didn’t say anything about them. My tires are showing some feathering. No indication of why I heard that bumping/grinding sound at high speeds in South Carolina.

Yes definitely on the PTU fluid change. None of the uncertainty others have reported on this forum. His tune-up is $198, very thorough. Sure beats the $300 from my Lafayette shop. I’m a bit early on this but might as well while I’m here.

BMS battery reset is different for each make and model. He has to look it up each time he replaces a battery. Even tho mine is 4.5 y/o he sees no reason to change it. Nor the alternator.