Multiple Errors - 05 4.0

[justinc87]

Hello all,

So I'm regularly getting 3 errors on my gauge set... Check Charging System, Check Fuel Cap, Low Oil Pressure (Gauge drops to 0, then bounces back). Along with these errors I'm getting a bogging down when I'm at idle every 2 minutes or so with this occasionally making my car feel like it's going to die at stops.
My initial thought was this was an issue with my Alternator, I had it tested at Oriley and was told battery is good and alternator is outputting 14.3. So that ruled out my idea of an alternator replacement. Anyone have any ideas on what would cause those multiple issues before I go and take it to a dealership? I feel it's gotta be some kind of electrical issue.

And I did do a complete reset, disconnecting the positive and grounding the positive wire for a while. This cleared all the errors minus Check Charging System, but they all eventually came back. And I also ordered a replacement OEM fuel cap too, no luck.

 

[08GT500]

Hello all,

So I'm regularly getting 3 errors on my gauge set... Check Charging System, Check Fuel Cap, Low Oil Pressure (Gauge drops to 0, then bounces back). Along with these errors I'm getting a bogging down when I'm at idle every 2 minutes or so with this occasionally making my car feel like it's going to die at stops.
My initial thought was this was an issue with my Alternator, I had it tested at Oriley and was told battery is good and alternator is outputting 14.3. So that ruled out my idea of an alternator replacement. Anyone have any ideas on what would cause those multiple issues before I go and take it to a dealership? I feel it's gotta be some kind of electrical issue.

And I did do a complete reset, disconnecting the positive and grounding the positive wire for a while. This cleared all the errors minus Check Charging System, but they all eventually came back. And I also ordered a replacement OEM fuel cap too, no luck.

OI Justin!
Hope you’re well, I agree with your thought, check your grounds first. The 05’s-07’s had issues with rainwater water leaking in through the Cowl (passenger side, but not limited to that) and getting by the Firewall & inside the poorly sealed SJB under the dash.
If going through the main ground wires..Battery to block, Block to Chassis, Battery to EEC & making sure they’re all solid, corrosion free, I’d next suspect that. It’s a PITA, but shine a light underneath & see if there’s evidence of that anywhere above the foot wells. Any rain of late?
There’s certainly other avenues, but check those, go through the fuse blocks & follow the wires under the dash, connectors.
This just start occurring suddenly one day when you went out to it & started it up?
Best!
-John
One incident that shows this issue..

Pics & Vid of 2005+ dash water leak fix

I've heard about the FORD TSB on the water leak behind the dash on the passenger side of 2005+ Mustangs, but I was hoping it wouldn't happen to me. Yeah right! (I'm not so lucky...) Wednesday night on the way to church to drop off the kids for VBS, we got hit by one of those South Florida...

www.allfordmustangs.com

 

[Bullitt95]

What he said.
If you have a digital multimeter, I suggest you perform an AC ripple test (YouTube has good instructional videos) to rule out the possibility that one of your alternator diodes is allowing AC current to leak into the main wiring harness.

 

[justinc87]

OI Justin!
Hope you’re well, I agree with your thought, check your grounds first. The 05’s-07’s had issues with rainwater water leaking in through the Cowl (passenger side, but not limited to that) and getting by the Firewall & inside the poorly sealed SJB under the dash.
If going through the main ground wires..Battery to block, Block to Chassis, Battery to EEC & making sure they’re all solid, corrosion free, I’d next suspect that. It’s a PITA, but shine a light underneath & see if there’s evidence of that anywhere above the foot wells. Any rain of late?
There’s certainly other avenues, but check those, go through the fuse blocks & follow the wires under the dash, connectors.
This just start occurring suddenly one day when you went out to it & started it up?
Best!
-John
One incident that shows this issue..

Pics & Vid of 2005+ dash water leak fix

I've heard about the FORD TSB on the water leak behind the dash on the passenger side of 2005+ Mustangs, but I was hoping it wouldn't happen to me. Yeah right! (I'm not so lucky...) Wednesday night on the way to church to drop off the kids for VBS, we got hit by one of those South Florida...

www.allfordmustangs.com

I've only had the car about 2 months now, but since you mention it, I did have to remove the clogged drain plug due to it coming through the cowl. I didn't think the amount that came through could damage much but it may have done it when the previous owner had it as well. The SJB is something that I haven't looked at yet so I will do that this evening. I appreciate your advice on this John!

If that's not the issue I'll try to do the ripple test you suggested Bullitt95.

Thanks for your input guys!

 

[08GT500]

I've only had the car about 2 months now, but since you mention it, I did have to remove the clogged drain plug due to it coming through the cowl. I didn't think the amount that came through could damage much but it may have done it when the previous owner had it as well. The SJB is something that I haven't looked at yet so I will do that this evening. I appreciate your advice on this John!

If that's not the issue I'll try to do the ripple test you suggested Bullitt95.

Thanks for your input guys!

Keep us posted, buddy!
Best!
John