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Power Steering Failure

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Old Nov 5, 2021 | 08:52 AM
  #551  
BrRx8's Avatar
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Anyone have any idea how long simply cleaning the connectors would last? ~2 years ago I had this issue and suddenly at low speeds the power steering as a dip in power & the wheel becomes difficult to turn.
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Old Nov 6, 2021 | 07:11 AM
  #552  
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Waterproofing the Connector?

Originally Posted by BrRx8
Anyone have any idea how long simply cleaning the connectors would last? ~2 years ago I had this issue and suddenly at low speeds the power steering as a dip in power & the wheel becomes difficult to turn.
Did you seal the front/top connector to keep water from getting in? As you probably read, this failure was first reported as a result of a coolant overflow. I also think that rain can get in while driving and affect the connection. My simple solution was to wrap each side of the connector with electrical tape to prevent water from running down the wires into the connector. While I can't say how long it lasted (my RX-8 was hit and totaled a few years after I made this repair.), my PS worked flawlessly.
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Old Apr 1, 2022 | 03:09 PM
  #553  
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Persistently intermittent EPS on my 2004. 139,000 miles.

Replaced the rack after the torque sensor tested out of spec (reading 15ohms on each loop). Worked for a week, then quit again.
I had less than 1ohm in the harness from the connector at the module all the way to the rack, so that wasn't the issue.
Pulled the EPS module out and opened the cover and found this:


Very apparent damage from corrosion or acid at the points where the edge connectors are soldered to the board. The brown stuff flakes off with your fingernail. It appears to have flowed to this side of the board from the other side via many of the small solder point holes near the connectors. I can't get the module any further apart without destroying it, but my money is a cap on the other side blew and spat acid everywhere. The big caps look great. Very disappointed to find the module has zero waterproofing around the connector or the cover plate. Some other aspects of this car make me think it may have spent a short amount of time with the nose under water at some point. Got a used module on the way from Ebay. Fingers crossed that one wasn't submerged.

If anybody has any tips on disassembling this module further without destroying it, I'm listening. If it is just blown caps on the back side of the board, they could possibly be replaced with newer solid state caps and render the module functional again. Might be worth pursuing since these seem to be NLA from Mazda.



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Old Apr 4, 2022 | 03:57 PM
  #554  
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Hi guys....
What's the name or part number of the harness that attaches to the steering rack harness?
Basically the gray connectors that go towards the EPS.
Thanks in advance.
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Old May 26, 2023 | 10:09 AM
  #555  
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Originally Posted by MazdaManiac
I am now beyond perplexed and exasperated.

As noted above, I've removed and replaced/swapped every component of the system except the rack itself.
I've pulled individual components and tested them against various scenarios, scoped the power sources, the signal lines the output of the EPS HU and read the codes from the EPS diagnostic.

I had consigned myself to having to replace the rack since it was the only component left in place and the same failure mode (bucking, vibration, self-initiated counter-steer, sudden increase and/or loss of assist, etc.) was always present, even when all other components were different or new.

This past weekend, I just figured I'd disconnect the EPS and drive unassisted in the NASA track event at Firebird.
I went into my sessions with it actually still connected and had it present all failure modes, including some wild self-steering that almost put me completely off track.
Eventually, the unit failed, the steering MIL came on and I drove unassisted.
After cycling the ignition for another session, the same thing happened again.
When driving home from the event, again - the same.

So, I parked the car, put it up on jack-stands and proceeded to change the turbo out (my center section had a bearing failure). BTW - it bucked and failed as I drove it into the garage.
After 2 days of sitting in the garage this way, I took it down off the stands and pulled it out of the garage.

THE ******* STEERING WAS AS PERFECT AS THE DAY I BROUGHT THE ******* CAR HOME.

Not a buck. Not a vibration. Perfect assist in both directions. No noises. No self-steer.

I've since driven it about 60 miles on local streets and the highway and gone through a complete heat cycle and many restarts as well as a car wash.

Still absolutely perfect.

WTF is going on here?

From the time it went on the jack-stands until the next time I drove it, the following things occurred:

The oil was drained
the coolant was drained
the brake pads and rotors were swapped for my street setup along with my wheels
The turbocharger was removed, which required lowering the front of the midpipe and the disconnection of the oil, water and air connections to the turbo and removal of the two motor mounts

That is it. These are ALL things I have done repeatedly in the past without them affecting the steering problem.
I did NOT disconnect the battery.
I did NOT disconnect any harness components, other than the oil pressure sender wire (so that it wont get mangled)

In the past, I had noticed that the steering got better after a track day or an Auto-X, but not completely fixed and it was still completely failed after this track event. It was only after sitting for a few days that it worked again.

Apparently, something is intermittent, but WHAT?

Now, I am waiting for the other shoe to drop. When will it just randomly fail again at highway speeds in traffic as it drives me up a k-wall and into the Salt River?!?!

I will buy beer, cigars and a hooker for whoever figures this crap out. I've had it.
YUP...exactly the same issue...my 2005 has 95k km. and all I did was jack it up to change the oil and the PS stopped working. I have continuity from the rack back to the EPS module relative to both power and the 3 smaller wires. Power to EPS module is fine...but no power steering...driving me crazy. Did you ever figure it out?
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Old Dec 1, 2023 | 06:50 PM
  #556  
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From: A Pacific Island.
I would suggest as a first step to address the dreaded 'No Steering' issue, to check the condition of your battery....

Try to start the car while it's hooked up, with booster cables, to another running vehicle.

My '03 had started to 'forget' it had power steering, but would be fine if I turned the ignition off while it was rolling, and 'bump' started it.
This told me it was probably seeing the cranking of the starter as a low voltage, enough to cause a no-steer light.
Battery wasn't very old, marked 04 of '17 but it had a hard life!
New Costco 124R installed, good like new.

Just a suggestion, worked for me....
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Old Dec 7, 2023 | 02:58 PM
  #557  
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This is an exceptionally long thread, so please excuse me if this has already been asked/answered, but it does seem related to this thread.

First a question. Does anyone know if the EPS fault light will not come on even if there is a problem with the system? It takes more effort than it should to steer, but the EPS fault light is not on. It seems balanced, in that it does not steer harder in one direction or the other, it just seems to be lacking the level of assist it should have. This was a similar symptom to what's been reported by others, it happened overnight. Never a problem since I have owned the car, then I get in to drive a few days ago and it's hard to turn the steering. This is a 2005 MT, base model. 22,000 miles, original owner. I sure don't want this thing going to the dealer hacks.
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Old Dec 13, 2023 | 03:08 PM
  #558  
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Well my PS quit on me again the other day. Thought I had that problem fixed.
It was just sitting in the garage. All I did was work on adjusting the clutch pedal. There is a connector coming from the ECU marked X-06 on the diagram. It looks like it ends up under the dash near the steering column.
Does any body know what this is and where it's at? I'll going over later to work on it.
I haven't done the connector elimination under the air box yet. The cleaning seemed to help the first time, but it only lasted about 60 miles of driving.
I think while I have it apart, I will check the connections at the computer as someone reported corroded terminals there. And also a report of corrosion at the 60 amp fuse location.
This is insanity.
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Old Jan 3, 2024 | 11:48 PM
  #559  
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From: PHX
Please need an answer quick







I fucked up yesterday just AutoZone with the universal redcap for some reason didn’t hold up right coolant discharge from overflow I believe caused intense humidity under the hood and now I got this going on happened before with rain just power steering. Cleaned greased all better. So I don’t have time unfortunately to pay attention to it. I gotta be at work in like four hours and I was just able to limp it home. but that said, should I go out there and disconnect the battery until I can clean and replace this Friday?
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Old Jan 3, 2024 | 11:55 PM
  #560  
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From: PHX
Originally Posted by Rock10
Well my PS quit on me again the other day. Thought I had that problem fixed.
It was just sitting in the garage. All I did was work on adjusting the clutch pedal. There is a connector coming from the ECU marked X-06 on the diagram. It looks like it ends up under the dash near the steering column.
Does any body know what this is and where it's at? I'll going over later to work on it.
I haven't done the connector elimination under the air box yet. The cleaning seemed to help the first time, but it only lasted about 60 miles of driving.
I think while I have it apart, I will check the connections at the computer as someone reported corroded terminals there. And also a report of corrosion at the 60 amp fuse location.
This is insanity.
damn bro, she heard that! that's why she does this to you. 🤣 but for real give her all the love. This journey never ends!

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Old Jan 4, 2024 | 12:07 PM
  #561  
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From: PHX
Originally Posted by Reoze
It was the rack.
hahahahaha. Only a real one would sit himself down like this. Proud of you punkin
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Old Feb 1, 2024 | 11:57 AM
  #562  
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Here is a simple video showing how to test your steering rack to make sure the motor is working.

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Old Feb 18, 2024 | 10:27 AM
  #563  
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From: UK, Essex
Lolll
thats normal.
it soldering paste/ flux residue.
Any many peopel like that post lollll








Originally Posted by inkyracing
Persistently intermittent EPS on my 2004. 139,000 miles.

Replaced the rack after the torque sensor tested out of spec (reading 15ohms on each loop). Worked for a week, then quit again.
I had less than 1ohm in the harness from the connector at the module all the way to the rack, so that wasn't the issue.
Pulled the EPS module out and opened the cover and found this:


Very apparent damage from corrosion or acid at the points where the edge connectors are soldered to the board. The brown stuff flakes off with your fingernail. It appears to have flowed to this side of the board from the other side via many of the small solder point holes near the connectors. I can't get the module any further apart without destroying it, but my money is a cap on the other side blew and spat acid everywhere. The big caps look great. Very disappointed to find the module has zero waterproofing around the connector or the cover plate. Some other aspects of this car make me think it may have spent a short amount of time with the nose under water at some point. Got a used module on the way from Ebay. Fingers crossed that one wasn't submerged.

If anybody has any tips on disassembling this module further without destroying it, I'm listening. If it is just blown caps on the back side of the board, they could possibly be replaced with newer solid state caps and render the module functional again. Might be worth pursuing since these seem to be NLA from Mazda.
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Old Feb 18, 2024 | 10:31 AM
  #564  
motodenta's Avatar
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From: UK, Essex
Here is the how the failed module looks like.
There is a Power mosfet TPD7203F which could failed.
it is more convinve to chnge whole unite than the mosfet itslef unless in future the story could changes. ( if someone read this post in future)








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Old Feb 20, 2024 | 07:23 AM
  #565  
VT_RX8's Avatar
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Just Clean it

Originally Posted by motodenta
Lolll
thats normal.
it soldering paste/ flux residue.
Any many peopel like that post lollll
I used to work in the circuit card assembly industry. That is definitely solder flux residue. Back around 1998 it became common place to use a "no clean" flux on things like this that are assembled to the board after the initial assembly and cleaning. The problem is the residue is hygroscopic (absorbs moisture), so if it is not in a sealed environment, the moisture absorbed by the flux makes it conductive and can cause problems with low level signals shorting out. Take a q-tip or pipe cleaner with some IPA (not beer, isopropyl alcohol, lol) and clean it, being careful not to use too much which could run to the other side and cause more problems. As you clean it, use dry ones to remove the loosened residue. This stuff can get very hard over time, so it could take a bit of rubbing, but it will eventually soften and come off. Hope this helps. Good luck!
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Old Aug 30, 2024 | 06:07 PM
  #566  
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From: Wilmington, Massachusetts
Hi. I see it here talking about cleaning the connectors. Are they the ones under where the airbox sits, connected to the center of the frame? (They look like ground wires). (Above the radiator fan).

My power steering light is on.

Thanks,

Chad
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Old Aug 30, 2024 | 10:26 PM
  #567  
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Originally Posted by cmaderia10
Hi. I see it here talking about cleaning the connectors. Are they the ones under where the airbox sits, connected to the center of the frame? (They look like ground wires). (Above the radiator fan).

My power steering light is on.

Thanks,

Chad
Two connectors right under the radiator overflow tube. There are many pictures.
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Old Nov 17, 2024 | 04:00 PM
  #568  
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Adding to sticky

Hi all I have read a good chunk of this tried cleaning connectors checking continuety on wires I am also a mechanic and i just desided to dip into this issue on my car so nothing in this thread seemed to help and my car was throwing 2 codes B1342 and C1099 the issue turned out to be under the fuse for the power steering theres a connector i cleaned it and it works as it should again
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Old Nov 17, 2024 | 10:33 PM
  #569  
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Originally Posted by Daz911
Hi all I have read a good chunk of this tried cleaning connectors checking continuety on wires I am also a mechanic and i just desided to dip into this issue on my car so nothing in this thread seemed to help and my car was throwing 2 codes B1342 and C1099 the issue turned out to be under the fuse for the power steering theres a connector i cleaned it and it works as it should again
I think that was mentioned somewhere in the thread.
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Old Mar 25, 2025 | 08:53 PM
  #570  
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Had the same issue and decided to replace the steering rack. Replaced btw also the EPS unit, but this wasn't the issue.

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Old Mar 4, 2026 | 02:07 PM
  #571  
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Originally Posted by emuman
Had the same issue and decided to replace the steering rack. Replaced btw also the EPS unit, but this wasn't the issue.

https://youtu.be/fRn1NiYqUlE?si=m-0Cqm-eUnO3Mnr-
BTW steering works, but for the first 15 sec when the car is cold after some time not using it, there is a strange behavior. The steering is fighting back like a force feedback steering wheel on a PC.
Plan to first change the EPS unit and then the steering angle sensor.
BTW there is a replacement for the torque sensor, part number ZZCT-32-693. Has anyone ever replaced it?
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Old Mar 22, 2026 | 06:55 PM
  #572  
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Im also experiencing issues with the power steering. Getting a code U1900 can bus comm error. Ive tried testing continuity and voltage, and it s all good, so ive opted for changing the module. IF that doesn't get it, ill replace wiring harness too.
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Old Mar 26, 2026 | 09:33 PM
  #573  
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I changed the EPS module and it fixed my power steering. Code u1900 still is a thing however. Oh well, at least it drives well now.
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