Power Steering Failure
 

My power steering failed last night.
It was fine when I shut the car down last, but on a cold re-start, the fail light was on and the steering was unassisted.

I know this failure has been covered already a bunch of times here, but I was hoping someone had "DIY"ed it at some point so I can internalize the parts layout before I start unbolting things.

I suspect that the connector for the intermediate harness is dirty/rusted/disconnected/moisture saturated or whatever.

Where is this connector, exactly? The FSM generally points to it being on the rad core support. Is it under the battery tray, the overflow bottle or the intake box?

Has anyone shot a meter across that harness from the rack connector all the way to the PCM box?

BTW - Checked the fuse (took me a minute - I never really gave that fuse on the battery positive a second look before, so I wasn't sure where it was. Pays to scrutinize the FSM) and it is OK.
Tried a battery ground pull, but still no joy.
I figure the sudden cold snap condensed some moisture or some mineral deposit.

By the look of the long and raging list of responses, I take it the answer to my question is "asphinctersayswhat?"

Either that or some knuckle head is going to blame it on your turbo. :spank:

Well, actually, in an indirect way it might be related to the turbo.

I had a coolant boil-over this summer and, from what I can gather, the connector I'm looking for may have been the recipient of some of that errant coolant.
Its also possible that some wire chafing happened.

Either way, I doubt its the rack or the control module.
If it is, I'm working with a friendly dealer here in Phoenix.

That happened to my car a few months ago,
I sprayed the connectors with contact cleaner and problem solved.

On my case the problem was mineral deposits......................

Manuel

Thanks Manuel!

Can you tell me as precisely as possible where the connectors are (other than the one on the rack itself)?

I'd rather not have to pull the intake and battery if I don't have to.

What needs to be pulled to reach these:
https://www.rx8club.com/attachment.p...id=92560&stc=1

I had similar problem a few months ago, but it has been working fine for 2 months since last time I disconnected the whole harness related to the power steering, and reconnected them all. The connectors you referred are under the bottom intake tray, next to the battery box, so you have to take out the intake tray. Those are the intermediate harness/connectors for the power steering motor & the torque sensor.

Sammy

Got it.
I pulled the intake and tray and started cleaning all of the connectors.
I'll hit the connectors on the torque sensor itself, as well.
I'll scope the connection from the sensor to the control unit and see if it is strange.
I'll post back once I get it all reassembled.

A descent DIY (with pictures ) on this would be would be great .....

Sucks dosen't if Jeff.
I had the same thing happen last year. Coolant boilover and next morn the PS light came on.
Drove it to the dealer ship and they replaced the rack,PWS (x3) to the warranty tune of $3059.30

After all that parts swapping the tech found the defective harness and replaced it . Works to this day.

I suspect most people that had the rack and/or CU replaced only needed a cleaning.

I should have taken pictures, sorry Brettus.

Essentially, you just pull the airbox and the two connectors in question are staring you right in the face.
Both are gray and oriented vertically, which is stupid since they fill with whatever spills on them. Of course, the overflow bottle has a release drain that is pointed directly at these connectors, so if you have a boil-over, they get saturated.

One of the connectors carries the power for the rack itself and has two super heavy wires running through it.
The other is a 3-pin connector that carries the torque sensor data.
Pull 'em, clean 'em and assembly is the reverse of disassembly.

Took about 2 hours, comprised of 1/2 hour of work and a 1.5 hour break in the middle.

Works like new again.

Thanks to everyone that responded!

I just checked my car and yep the two connector are gray as you mention,one have two big cables and the other have 3 green cables in one of the ends.

Manuel

Just disconet the positive power cable from batt. wait for 40 secs. and connect then again for the EPS Ecu reset. This fail is common when the altenator go down from 11.5 VDC or lower the EPS light come on.i Resolve it changing the alternator for a 200 amp alternator. once changed the alternator i have no more problem with the EPS Unit.

funny.

was not here to help for this.. i knew they were under the bat plate... nice to know that the angle is bad for moisture...

nice write..

beers :beer:

Isn't a power issue and a full reset didn't fix it. Plus, I keep my car on a charge box when I'm working on it, so I have way more power than I need.
Charge voltage was 14.5v

It was a failed connector. I cleaned it and now it works.

Glad ya got'er fixed Jeff. With limited headache.

Mine failed.. they replaced the control unit..and it worked for 2 days....... I cleaned the connectors....and it worked for about three months.

At that time the sensor in the rack failed..and they replaced the rack and the int harness under warranty.

I don't know if the sensor failure was a new failure...or if the poor connection damaged it in some way ( I know...doesn't make sense :) )

I do know that when you install a new rack...it's a bit tempermental resetting the sensors so the DSC works properly. It doesn't like it if the steering angle and the rack position sensor don't agree

Thanks! It wasn't a big deal, I just wasn't in the mood to waste time today on that.

Supposed to be. They aren't, just like all the other connectors on the car.
They "resist" moisture, but if you pour hot coolant over them and then heat-cycle it, it will pass some material through the grommets and mating surfaces via capillary action.

Really, the only "water-proof" connectors on the car are the ones that are totally un-insulated, like the starter motor.
The connectors on the tranny are better because they have a rubber boot.
The connectors on the OMP, APV and coils are just stupid.

Well, it did it again last night.
Only this time, It happened at WOT in 4th gear at nearly 120 MPH!
Fortunately, I was going down a perfectly straight section of road.

I guess I'll go clean the connectors again.

Do I remember correctly that some people had the intermediate harness replaced to solve this issue?

yes.

damn glad your ok jeff

Any idea what the cost on that part is?
I'd rather not be bothered with a warranty visit...

Well, cleaning the connectors fixed it again. I don't know what the problem is exactly because they looked clean.
Probably not enough spring pressure on the contacts.
If it fails again, I'll pull the intermediate harness, re-crimp the mating surfaces of the connectors and probably re-wire it for good measure.

BTW - just for grins, I tried a battery-pull for a couple of hours and it didn't clear, so it isn't just a "glitch" in the detection scheme.

sorry - dont know the cost

Glycol this....
 

Mine went after a boil-over too.

Dealer replaced the piece, IIRC it was in the $200 range.

S

Thanks! Dannobre got me the PN and price. Its around a buck-20.
Probably worth it to buy one rather than construct one since I'd be reusing the connectors, anyway.

This time, it appeared that the torque sensor connector on the rack itself was the culprit.
After cleaning the upper connectors on the rad, the fault remained. It cleared as soon as I cleaned the one on the unit itself.
I used a fair amount of dielectric grease this time. Hopefully that will keep out the gremlins.

hey Jeff, you might want to let Todd (flashwing) know about this! When his car purged coolant on the dyno it might have hosed his connectors, too!

This is one thing that scares the shit outta me- I'll be hauling ass and I'll loose my PS, or I'll be mid-turn and loose it. Scary stuff!

Well, fortunately, at speed it doesn't matter much since most of the assist is out by then.
Its a low speed where it really helps you out.
The scary part was that it wanted to give me too much assist at high speed right before it quit, which made it really twitchy, but only in one direction!
If you don't expect it, you can suddenly steer way too hard.

I removed the OEM overflow hose (which is 3 inches long and pointed right at the connectors) and replaced it with a 3 foot section that purges the fluid right to the ground in the middle of the air tray, so it doesn't splash on the tires.

If that is your arm in your avatar - you won't have a problem .
I'm no body builder & i had no problem steering the car when I had this problem.

At a complete stop, with 235 tires up front, it is almost impossible to turn the wheel.
I had to brace myself on the floor and use both arms and all my weight to turn the wheel enough to back out of a parking space.

LOL yeah it's my arm. It's not so much the effort required but the surprize (being caught "off guard" if you will) of suddenly loosing PC and freaking out that worries me more!

Do you reckon its the same symptoms as this.

http://www.youtube.com/watch?v=f_V1vS8Ndnc

Not nearly that severe, but I suppose that is possible.
It sounds like the rack motor on that car just "took off" without the feedback from the torque sensor.
That might even be a failure of the control module.

Now Im going to Take that hose out, and buy one thats 3 feet long and stick it out of that area.

In the mean time, Im going to buy some coolant cleaner and spay on that Area.

Thx :)

My PS failed this afternoon. Turbo conversion was finished on thursday, had several days of hot weather then a cold snap today resulting in the fail light coming on (to match the CEL thats staring at me) and no PS.

Will try cleaning up the connectors and reporting on result.

Hi Rortor psycho - glad to hear your turbo is in . How about starting a thread telling us what you ended up with .

Will do.
NZ Performance Car Magazine did a photo shoot on it yesterday which was pretty cool.

What model and make of the 200 amp did you get and where did you get it please?

This thread shows up just in time,mine failed yesterday. Well, it has done it before but I just restarted it and it would work again. Yesterday it would not repair itself, yet this morning it worked up until I stoped for lunch. Now nothing I do helps, guess I have to go find those connectors.

Funny thing I notice is how many people here would rather hastle finding it themselves and doing the work then go to the dealer. I really like to company as the dealer thing is such a waste of time and energy. So I'm not so crazy afterall.

I'm smaller and older then Jeff and manevering through In and Out Burger without the PS is work.

I'll let you know what happens here.

Heh. I've given up any sort of excercise since the steering failed - I get plenty just trying to parallel park!

I may give up and bring it to the dealer. I pulled and cleaned all of the connectors and crimped them a bit tighter, yet I still get a failure after everything gets warm and I hit a bump or two.
I guess there is the possibility that the torque sensor has actually failed.

Though I know the tech that will do the work, I worry about all of the other yokels at the dealership monkeying around with a toy like mine.

mine failed last friday. I drove the car to work, parked it. Later I tried to drive the car out for lunch and it had no power steering. so instead I drove it to the local dealer and they apparently knew of a common issue in regards to the connectors. They pulled the connectors and told me they took it apart and resoldered the joints. The service manager pointed to the two connectors sitting between the radiator fans as the connectors they worked on.

Power steering has been functional since.

btw, I have never had coolant overflow.

Re-solder, huh?
I might have to try that.
Considering they are not soldered to begin with (they are crimped), solder might help out.

I'm pretty sure my failure is at the connector on the rack itself at this point, since re-seating that is what brings it back (for a while).

If you don't read this forum don't have this car.
The time between my two posts is how long it took to fix.

I have that same extra problems with dealers also Jeff.
Now that your's has failed again I'm not so confident in my fix. The only way I'll know is to wait.

Soldering on the stock connectors? I'd have to get a closer look but that usually isn't possable or probable. I doubt they are factory soldered, that would take to much work on their part. If mine fails again I'll look into it.

You're to fast for me MM. But that backs up what I thought, they are crimped. I hope mine isn't the rack connector I hate getting under cars. Also if it is the rack connector then it probably needs a new rack as the wiring will be internal and that's where my dealer phobia stops.

The Fix
 

I pulled out the sub-harness that connects the power steering rack to the connectors at the top of the radiator.http://www.mazdamaniac.com/images/mi...ss/harness.jpg
It has two connectors at each end - one for the actual power supply to the rack which is two 10AWG wires and another for the three wires from the torque sensor. http://www.mazdamaniac.com/images/mi...connectors.jpg
It also has a ground strap that attaches to the rack and the middle engine bay crossmember that mounts the battery, airbox, fusebox and PCM case.




Once the sub-harness is out, it is just a matter of removing all of the tape and split-loom cover and then separating out the torque sensor harness.
http://www.mazdamaniac.com/images/mi...s/stripped.jpg
http://www.mazdamaniac.com/images/mi...or_harness.jpg

Once that was clear, each of the three wires and pins can be pulled from the connectors by relieving the plastic clips with a micro screwdriver.
http://www.mazdamaniac.com/images/mi...onnector_1.jpg
I cut off all of the wire, removed the insulating grommets and reassembled the harness with three fresh, new wires that I soldered to the pins.
http://www.mazdamaniac.com/images/mi...rness/pins.jpg
Reassembly is the reverse of assembly.

Hint: Mazda does make a countermeasure harness for that issue. It is not a TSB so you will need the assistance of a Mazda dealer to call techline to get it.

Yes, I'm aware of that.
If you are under warranty (and can stand having a dealer man-handle your car) there is a replacement part.
If you want to buy the part directly (F151-67-SH0A which supersedes F151-67-SH0B), its about $100.

This solution took almost the same amount of time as a replacement (plus 20 minutes) and was free.

wow - great DIY MM

How did Mazda know to issue the part as "SHOB" so that they would be able to label the replacment "SHOA"???

I'm PMing you on a few min. about something else.

That does seem to hold true with a lot of Mazda parts.
They issue "revisions" mid production that move up the alphabet as if they know they are shipping a sub-standard part.

MM, so you figure your steering problems are fixed now? Find the culprit?