2003 Z4 Hydraulic Power Steering Conversion

This is my guess, if you know NSCexpert you will know what I'm taking about. Get a MK60.C20 DSC module, use BT91/DU91 VO to code it and it should ignore all the related communication code since Z4M does not use the EPS and is native hydraulic
 
ivanchen1211 said:
1. The steering angle sensor sits on the lower side if steering column, nothing to do with EPS.
2. The steering angle sensor connects it's signal through D-can and not to EPS so event if you disconnect the EPS it will still have signal. Mostly the OP have to re-calibrate the angle
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Thanks for info! Would having the sensor recalibrated address the lack of signal from the steering sensor? I would assume the sensor would at provide some signal. I'm going to pull the under dash panels and take a look at the sensor anyway.
 
10Terp said:
Thanks for info! Would having the sensor recalibrated address the lack of signal from the steering sensor? I would assume the sensor would at provide some signal. I'm going to pull the under dash panels and take a look at the sensor anyway.
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1. please share your VIN 2. you need to read the codes, second . 3rd provide the assembly number of those modules that has error code about missing signal.

As previous said, the steering sensor LWS connect to CAN directly, so try to see if your INPA or ISTA or scanner is able to read real time steering angle. If not or the angle is in correct, re-calibrate it. If you are having 5E40 angle implausible, replace the brush in the sensor.
I've done this on both on my E46 and E85, will make a video on how to do it on E85, but basically the same, you need a vise grip to press the upper and lower lock clip to push the sensor down and disassemble it.
Replacing steering angle sensor with out removing column
 
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ivanchen1211 said:
1. please share your VIN 2. you need to read the codes, second . 3rd provide the assembly number of those modules that has error code about missing signal.

As previous said, the steering sensor LWS connect to CAN directly, so try to see if your INPA or ISTA or scanner is able to read real time steering angle. If not or the angle is in correct, re-calibrate it. If you are having 5E40 angle implausible, replace the brush in the sensor.
I've done this on both on my E46 and E85, will make a video on how to do it on E85, but basically the same, you need a vise grip to press the upper and lower lock clip to push the sensor down and disassemble it.
Replacing steering angle sensor with out removing column
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Thanks! I will get back to you on Friday when I have time to get to the car. I looked at a few pics of my steering column when I had it out of the car and honestly I think I just forgot to reconnect the SAS when I reinstalled the column.

In the meantime, I bought a used purple tag rack and LF30 to have backup parts in case I need them. Also bought an LF30 seal kit. Once I have figure out what’s wrong I’ll sell off the extra parts.

I’m pretty sure the rack I got from the wrecking yard car is a Maval rebuilt rack. From some quick searching it seems these racks aren’t great.
 
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10Terp said:
Took the car for a test drive finally, and something isn't right with the PS system. A few issues:
  1. The steering will not return to center after turning. It basically locks in place and you have to steer it back to center. My understanding is this is typically a caster issue, but the caster on our cars (I think) is not adjustable. I did also replace the lower control arms and outer tie rod ends and did an eyeball alignment, so I supposed it could still be alignment issue (it pulls hard to the left on driving).
  2. The steering still feels quite heavy. My first suspicion was a tight strut, so I got the front wheels off the ground and disconnected the tie rods and swaybar links on each side - both struts rotate fine and don't feel excessively tight. I did notice the struts seems to change angle slightly as you rotate them. For example, if I swatch the top part of the strut from the wheel well while rotating it, the angle changes slightly and the rubber on the upper strut mount bends a tad. Also, with the car started up turning the wheel with tie rods disconnected is still quite heavy. I believe I have a yellow tag rack which is supposed to be heavier, but it seems almost too heavy.
  3. Steering angle sensor lights. I stupidly threw away my EPS motor, which I'm kicking myself in the head for. Now I've got DSC and a yellow brake light on that won't go away. Using my Creator C310+ it shows me the lack of communication from the steering angle sensor is the culprit.
Certainly open to feedback on any of these!
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I've looked through all the module settings, I think after you connect LWS steering angle sensor, all you have to do is code EPS in cluster to not active
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ivanchen1211 said:
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I've looked through all the module settings, I think after you connect LWS steering angle sensor, all you have to do is code EPS in cluster to not active
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Back at it. Most issues largely solved. I was convinced the hydraulic steering system wasn't working and was getting air stuck in the rack. Went through two racks, two pumps, to come to the conclusion that everything is fine and the steering is just heavy. Had the car aligned yesterday and it tracks straight and returns to center.

Dealing with the SAS still, though. I plugged it back in, and the 3 lights went off. Then I drove it to the alignment shop and the lights came back on (to be fair, the alignment was WAY off). I then reset the codes with my Creator 310+ and the 3 lights came back very quickly. Wondering if I have to do some sort of reset or re-baseline for the sensor. When I put the system back together I was lazy and, to get the steering wheel straight ahead in the lock-to-lock range, I did rotate it over a few splines on the shaft. All that is to say, I'm wondering if the SAS is detecting that and not liking it and I need to figure out how to reset where 0* of input is on it. Open to suggestions there and thank you for your help!
 
10Terp said:
Went through two racks, two pumps, to come to the conclusion that everything is fine and the steering is just heavy.
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I think that's just how it is.

The hydraulic set up on my M is considerably heavier than the EPAS I had in my 3.0Si.
 
Hey all. Just an update. Used Tool32 to reset my steering angle sensor and no more lights on the dash! The swap is effectively complete. Time to drive!
 
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