Limp mode and weird voltage issues

[Joshled1993]

Please help!! 2010 mustang gt 4.6 5 speed manual. with mods, cat back h pipe, cams, throttle body, cold air intake. Has an aftermarket touch screen stereo that also controls the air system. I drove the car for a week after buying it. Ran great, plenty of power. Fell in love with it. Parked it Sunday after a drive. Got in it Monday to take to the store took off down the street and orange wrench came on the dash and car cut out. Would still run and drive but cut out a lot and lost a ton of power. I’m guessing this is limp mode. Checked codes and showed a lot of codes for sensors. And cam sensor circuit bank one and two open. I replaced tps and maf sensors. Didn’t make a difference.. I’ve ready a ton online and literallyy anything can cause limp mode. Idk where to start. Anybody else have these issues?

 

[Dino Dino Bambino]

Have you pulled any diagnostic trouble codes from the ECU?

 

[Joshled1993]

Yes we put an obd2 on it. There was like 16 codes all for sensors and weird stuff. Nothing directing to one single issue. Having all those things go bad at once is very rare. One mechanic told me maybe repointing the pcm harness and another guy told me he thinks it’s a short behind the aftermarket stereo

 

[bambam 06]

Have you taken it back to the seller?

 

[Joshled1993]

No I traded with a guy a few hours away. I’ve tried messaging him but no response

 

[DieHarder]

When you have that many codes look for something common to all of them....like power or grounds.

Alternator - Do you have a Volt/Ohm meter? If not, get one and check the running voltage across the battery. Should be 14.5 volts DC or better. If not, start looking at the alternator and grounds. Also check the AC running voltage as well. Should be in the mili-volt range if you read anything.
Grounds - Check/clean major grounds. Many of our cars are 15 - 20+ years old and the battery/ground cables have seen better days. Easy to check if you have ground issues. Do a Voltage Drop Test - Using a VOM (on Volts DC w/the car running) place one lead on the body of the alternator and the other lead on the ground at the passenger strut tower. If you're reading voltage your grounds need work. Low voltage/poor grounds will cause all kinds of mayhem in these cars.

Hit the Books - When all else fails use the manual to troubleshoot (maybe should be first on the list?).

Ford Workshop Service & Repair Manuals - fordrepair.info Home

Ford Workshop Service & Repair Manuals - fordrepair.info Home

iihs.net

Ford Workshop Service & Repair Manuals - fordrepair.info - 2005 Mustang 2005 Mustang Powertrain control and emissions diagnosis

Ford Workshop Service and Repair Manuals, 2005 Mustang Powertrain Control and Emissions Diagnosis

iihs.net

Dealer diagnostic - Sometimes it's worth the money (usually ~$200) to have a dealer scan the car for what the problem is. I've done it a couple of times and glad I did (was going in the wrong direction) though I don't recommend having them do repairs if you can avoid it.

Post the list of codes you're seeing. There's some pretty knowledgeable members on this forum who may be able to help narrow down what's wrong or at least eliminate false leads.

 

[Joshled1993]

Ended up just being fuse 47 thanks everyone

 

[Pentalab]

Ended up just being fuse 47 thanks everyone

what does fuse #47 do ?

 

[Joshled1993]

I’m guessing it supplies a bunch of sensor circuits and when it goes bad, the car goes in limp mode

 

[DieHarder]

Located in the BEC

Fuse - F47
Size - 15 Amp
Circuits protected - AC Clutch Relay; EVAP Canister control solenoid; EGR module; Oxy sensors; VVT solenoids; Inlet manifold runner control; Auto trans; EVAP purge valve.

 

[Shane361]

What DIEHARD said....check your alt voltage with the AC on full blast. That many things going wrong can happen when you are operating outside your voltage area.

 

[Autokyrios]

Check your grounds (engine grounds).