ap1 torque sensor neutral position recalibration

[solman182]

hi folks,

I'm new to the oz Honda forums. I've had a Honda s2000 for a few months now that was lowered on buddy club n1 coil overs. it had been sitting for a while with a flat battery before I took delivery and started fixing it up. as it's technically my daily drive I had to raise the suspension as it was just too impractical having it so low on Sydney roads.

anyway, for a while now it's been pulling to the right. it's also been more effort to turn the wheel to the left than to the right. almost like you have power steering active turning right but not to the left.

so I take the most logical approach and have my car raised at pedders to a now legal ride height. I then take it to my mechanic and have him do a four wheel wheel alignment, check the condition of the rims and tyres and tyre pressures.

all seems well, except the fact that it still pulls to the right. so we swap the front wheels around to see what happens and it's still pulling to the right.

finally my mechanic takes the car for a drive and switches the car off while driving and reports the steering returned to normal and says the steering rack might need to be replaced.

now my mechanic is a great mechanic but not a honda s2000 specialist so I take his advice on board, start shopping around for replacement steering racks and do some googling.

at this point I also notice that the steering is easier to turn left or right when standing still. i now have this feeling that the steering rack may be ok.

I do some more googling and find out about EPS and what that light is for. mind you the Eps light is off while driving.

I find the Procedure to read the eps codes and clear them. so I started by clearing the codes. I figured they might be old codes, and if there were still issues it would raise a code.

after clearing the codes I took the car for a 5 to 10km drive through the hills area and short the scs connector again with a wire. no codes were present. I thought I might as well use this time to recalibrate the torque sensor neutral position.

the thing is, when I start the procedure, I short the scs connector, turn the wheel to a 45 degree angle and turn the key to ignition (II). the weird thing is the eps light won't turn off unless I start the car. at which point it stays off.

could I have done something wrong? should I try something else?

so today I have the car taken to Honda in blacktown by a friend of mine and ask him to ask Honda to reset the torque sensor neutral position. to which the sales guy responds "I don't know what your talking about". he then introduces us to their "resident expert" who says he doesn't know how to do that and doesn't want to touch the car because of it which is fair enough.

then the sales guy says that the s2000 never came with eps and that's when the sales guy was introduced to an s2000 dashboard which clearly shows "EPS". the mechanic did offer to check it over to see why it's pulling to the right despite us telling him what we'd already tried. the sales guy as well tried to book the car in (at $110 p/h) to figure out why it's pulling to the right and which point we ran away...

and here I am.

*waves*

so yes, any ideas, suggestions, did I stuff something up?

btw thanks for getting this far and reading my life story.

[solman182]

ive read somewhere about cleaning the eps unit which I've heard lives in the engine bay. thats also on my list of things to do this weekend.

[aaronng]

You checked if the brake calipers on the right side are stuck? If the car has been sitting for a long while, long enough to have its battery go flat, then the brake caliper piston on the right side could be siezed and hence you get pulling to the right when driving. You can easily check by driving for a while and then stopping to feel your car rims by hand. The one which feels hotter is the corner with the stuck piston. If they all feel cold, then carefully feel the disc rotors. They can be very hot, so be careful. I am guessing that if it has been sitting with the handbrake on for a long while that it is the driver's side rear caliper which has siezed. You just need to push it back in with the caliper tool (rotate while pushing) to free it up if this is the problem.

[VeYzZii]

Im pretty sure it can be the EPS. Give the EPS module a little tap when the car is on and see if the wheels flinch. Weird that the codes did not come back after a drive. You shouldve checked the EPS codes before resetting. Maybe just takes abit more time. When doing the torque positioning, make sure you hold the wheel in that position, and not just turn and leave it.

But what confuses me more is the only way to DIY it is to short the DLC, but we dont have OBD ports (in aus). So im guessing your shorting something else?

PS. The module is located passanger side next to ABS. It should have a SHOWA sticker. This is how you will see it:http://www.google.com.au/imgres?star...9,r:0,s:15,i:5

[AusS2000]

PS. The module is located passanger side next to ABS.

Ummm, ABS and EPS are on the drivers side.

And we don't have OBDII on MY00, but we do have PGM, SCS, DTC and several other abbreviations.

[AusS2000]

And 2001 (IIRC) have ODBII.

Apart from that, spot on!

[solman182]

thanks folks, looks like I have area things to check this weekend.

yeah I recall I didn't exactly do the recalibration procedure the same way I did the reset. for what it's worth the error code was 34 but hasn't resurfaced and probably why it didn't work.

just for clarification, there were two connectors in some sort of green rubber surround on the drivers side tucked under the ac controls. one is a blue 2 pin connector and the other was a 3 pin connector. I deduced the two pin to be the SCS connector and shorted that. figured it must be the right one since the malfunction indicator lamp turned on and the eps light started flashing.

[VeYzZii]

Ummm, ABS and EPS are on the drivers side.

LOL my bad.

thanks folks, looks like I have area things to check this weekend.

yeah I recall I didn't exactly do the recalibration procedure the same way I did the reset. for what it's worth the error code was 34 but hasn't resurfaced and probably why it didn't work.

just for clarification, there were two connectors in some sort of green rubber surround on the drivers side tucked under the ac controls. one is a blue 2 pin connector and the other was a 3 pin connector. I deduced the two pin to be the SCS connector and shorted that. figured it must be the right one since the malfunction indicator lamp turned on and the eps light started flashing.

Yea. 34 is 'a problem with the main micro-computer'. Theres a series of tests in the service manual. Makes you check continuity through some pins. I know my EPS module has had it so im sourcing a new one. But yea you cant do torque neutral with SCS. Only for checking really.

[solman182]

so the cars been driven for the last few days with no codes coming up again.

ok so the problem was the fact I wasn't holding the steering wheel when i turned they key, then I faced a new problem.

it wouldn't save the new setting. the eps light would flash twice to indicate clearing the code but after 5 seconds it didn't flash 3 times. this was because the car wasn't quite on a level surface. once it was the process was completed successfully.

so now it no longer requires the strength of a gorilla to turn left.

having said that it still drifts to the right though but it's doesn't seem as bad.

still haven't checked brakes though as suggested above but it is a long weekend in syd.

[solman182]

ah yes I should also mention I do have the service manual but I discovered it's not for my ap1 as mine doesn't have an obd II port.

the codes should be the same though.

oh! I forgot to tap the eps module thing. I've got a theory that you might be onto something. I'll have to do that tomorrow and the checks as well from the service manual.

[solman182]

hi folks, quick update. I checked the brakes and they seem all good.

I did notice right next to the battery is a fuse box which had a 70 amp EPS fuse. I unscrewed it (battery disconnected before I did this) and pulled it out. of course that meant no EPS. now I know what it feels like to have no EPS at all but it did drive straight as an arrow.

so I reconnected everything and so it seems I have some eps when turning left at speed and normal eps when turning right. it still veers to the right though when driving straight down the road.

I'm about to check the EPS connectors and clean them and do the troubleshooting for DTC 34.

[solman182]

just a quick update, ITS FIXED! car drives straight as an arrow!!

It ended up being the torque sensor that was the problem. Even after recalibrating the torque sensor neutral position, the car would still pull to the right. I performed the testing in the service manual by checking each of the 3 pins on the torque sensor connector for continuity. While there was some resistance (around 500 Ohms i believe) it looked ok to me. The manual then asks you to test the middle pin of the torque sensor itself for continuity. Funnily enough, i couldn't get continuity from any of the 3 pins on the torque sensor.

So i found a wrecker in Sydney who has no idea on the price of S2000 parts but i managed to pick up the torque sensor only (he originally wouldn't sell it without the steering rack as well) and managed to knock him down from $350 for the sensor to $150 after some arguing and walking away. Not sure if $150 is a good deal or not on a used sensor though.

Just in case anyone is curious here's how i removed the torque sensor. I'm sure there's a better way of doing it, but i sure didn't see it in the service manual.
1. Disconnect the battery
2. Use a 10mm socket and extensions to remove the two bolts (don't lose the washers) holding the steering column uni joint knuckle thing in position
3. Knock the uni joint knuckle thing back up towards the steering wheel (turn the steering wheel to give you better access if you need it). I used brass hammer which i think helped to avoid damaging the joint
4. Once you hammer it back far enough (progress is very slow) it should fall off the shaft connected to the torque sensor
5. Unclip the 3 pin torque sensor connector
6. Undo the two 12mm bolts holding the torque sensor to the steering rack
7. jiggle and pull on the torque sensor to remove it. Don't hold the shaft too tight as it needs to rotate to be removed from steering rack
8. Replace the o-ring that sits between the steering rack and the torque sensor housing making sure to grease the new o-ring
9. I added some grease to the end of the torque sensor which fits into the steering rack. I don't think it needed it but i've had no problems so far
10. Re-insert the torque sensor and bolt it back in. The bolts will pull the torque sensor back into the steering rack
11. Make sure the steering wheel and wheels are in the straight ahead position and fit the uni joint back over the lower shaft
12. Hammer the joint back down the shaft till it's back in its original position
13. Bolt uni joint in place
14. Reconnect the battery
15. Perform the torque sensor neutral position recalibration as per above
16. Take it for a drive and check the bolts are still tight