2014 GT – Intermittent power steering & AdvanceTrac failure – losing my mind

[ryanoneill]

I've been chasing an issue on my 2014 GT for a while now and I'm hoping someone here has seen something similar.

It started about a year ago when I was driving and randomly got a "Service AdvanceTrac" message and the power steering cut out for a few seconds, then everything came back. At the time I replaced a 100A fuse and the issue completely went away, so I thought it was solved.

Fast forward to recently and the problem came back, but now it's way more aggressive and unpredictable. Since then I've had a new battery and multiple steering racks swapped in. My mechanic checked the grounds and cleaned the connections when doing the swaps. One of the racks actually felt noticeably better—tighter and more responsive—but even with that one the issue still came back, which makes me think the rack itself isn't the root cause.

After already swapping two racks, I also took it to Ford. They ran their pinpoint test and said it was the rack and couldn't find any voltage issues, but after they cleared the codes the car actually drove fine for a while under normal conditions, which made it even more confusing.

The strange part is the pattern. The car drives completely fine under normal conditions when codes have been cleared or right after a new rack is swapped in. I dropped it off with my mechanic and he had it for a few days, drove it constantly, and couldn't get it to happen once. As soon as I got the car back, I did a few hard pulls and broke traction a couple times, and right after that the power steering and AdvanceTrac shut off instantly.

At this point it seems like it only happens under load, especially during hard acceleration or when the tires break loose. I've noticed that sometimes the power steering will briefly come back while driving and then cut out again.

Right now I'm trying to figure out if this is a voltage issue under load, a bad ground or wiring problem, or a steering angle sensor or module issue.

Before I keep throwing parts at it, I wanted to see if anyone has had power steering and AdvanceTrac fail specifically under load like this. Any ideas or things I should check would be a huge help.

 

[ryunker]

Please list your fault codes you mentioned

 

[86GT351]

Ford Racks or Aftermarket? Was the EPAS system properlu updated showing the new rack to the car? As crazy as it sounds, when new electrical components are installed, many times the systme needs to be updated.

 

[Juice]

This is most likely a CAN bus issue.
The PCM, EPAS, ABS and cluster make up the stability system via the can. Best guess at this point is moisture/corrosion in the ABS connector. Could also be sjb corrosion even though sjb is not part of the stability system, it could still short by the can. Or any one of those 4 modiles.
A corrupt tune is also possible.

 

[ryanoneill]

Please list your fault codes you mentioned

Ford got C1B00 - steering angle sensor inside steering gear bad

 

[ryanoneill]

Ford Racks or Aftermarket? Was the EPAS system properlu updated showing the new rack to the car? As crazy as it sounds, when new electrical components are installed, many times the systme needs to be updated.

They were used OEM Ford racks, not aftermarket. I'm honestly not sure if they were properly programmed/updated to the car though but my mechanic said he did update it. The issue is so intermittent that it's making diagnosis really difficult.

 

[ryanoneill]

This is most likely a CAN bus issue.
The PCM, EPAS, ABS and cluster make up the stability system via the can. Best guess at this point is moisture/corrosion in the ABS connector. Could also be sjb corrosion even though sjb is not part of the stability system, it could still short by the can. Or any one of those 4 modiles.
A corrupt tune is also possible.

That honestly makes a lot of sense with how random the issue is. It can go days driving perfectly fine and then suddenly lose power steering/AdvanceTrac after hard acceleration or spinning the tires. Ford pulled C1B00 for the steering angle sensor in the rack, but I'm starting to think it could be a CAN/voltage issue triggering that code instead of the rack actually failing.

I do also have an Ngauge plugged into the PCM full time, I tried driving with it unplugged to see if having it plugged in full time was an issue but the same issue still happened.

 

[Juice]

Remove tune, restore to stock.

 

[ryunker]

Ford got C1B00 - steering angle sensor inside steering gear bad

Action
This DTC sets when the ABS module receives incorrect data from the PSCMregarding the steering wheel angle sensor input. RETRIEVE and REPAIR all non-network DTCs in the PSCM.

Please do a full system scan and post those codes for more help please.

 

[ryanoneill]

Remove tune, restore to stock.

Last night I reverted car back to stock tune and then reflashed the Lund tune and at first the car seemed fixed. Did a few hard pulls and spun the tires with no issues.

Today after about 20 minutes of driving though, the power steering cut out for a second while turning off the highway and the traction control/AdvanceTrac lights came on, then immediately went back to normal. It did it again a few minutes later parking.


Starting to think it may be heat/electrical related since it only happens once the car is fully heat soaked and under steering load.

 

[Juice]

I said revert to stock and test. Not reflash the aftermarket tune. Thats just time wasted.

 

[ryanoneill]

I said revert to stock and test. Not reflash the aftermarket tune. Thats just time wasted.

I get what you mean. I just didn't want to leave it running on the stock tune since the car has long tubes and a ported 18 intake manifold.

What was interesting though is after reflashing the issue completely disappeared at first, then only came back intermittently once the car was fully heat soaked and under steering load but didn’t fully shut down the power steering. That's what's making me lean more toward some kind of intermittent electrical/heat related issue.

 

[ryunker]

I get what you mean. I just didn't want to leave it running on the stock tune since the car has long tubes and a ported 18 intake manifold.

What was interesting though is after reflashing the issue completely disappeared at first, then only came back intermittently once the car was fully heat soaked and under steering load but didn’t fully shut down the power steering. That's what's making me lean more toward some kind of intermittent electrical/heat related issue.

Please do a full system scan and post the results.

 

[ryanoneill]

Please do a full system scan and post the results.

 

[ryanoneill]

View attachment 116019

 

[ryunker]

View attachment 116020

Often times while working at the dealer, basics get overlooked. Your communication error is relevant here, on the rack connectors verify the powers and grounds using a strong load like a double element lamp on the battery power and ground, and the key on power and same ground. Verify the lamp is bright, if not fix that issue. If the bulb is bright on both circuits, the connectors (female terminals) size is the next culprit, your rack has been changed before from your post, some techs shove tools in there to verify the powers and grounds and create an issue by oversizing the terminals. I do believe patience on that and you will locate the issue. If/when the rack looses power, it will loose communication and cause this issue. I have a file PDF trying to attach to assist, if it does not attach, send me a pm with your email and I will get it to you. Good luck