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95 Manual NSX EPS Problem

9 January 2021
Hi everyone, sorta new experience with NSX, i recently bought a 95 NSX Manual with EPS fitted as standard. However, the EPS decided to fail and my mechanic have taken out the EPS module and examine, it brought out the code 22 which i research its a common problem, now i m deciding whether i should get it fix or buy a new module....

But i just want to ask is the EPS module from a 91 Auto NSX is different to the 95 Manual? I might be able to get one to test if they are the same?

Also, would there be problems if i leave it as it now which is unplug the EPS module and drive but i m worry as the car fitted with electronic steering rack?

Much appreciated.
Short answer on interchangeability between 1991 and 1992 is no. Check the part number on you 1995. For North American cars you should have an integrated controller / power unit and it should be 39980-SL0-A00. The 1991 models used a separate controller 39980-SL0-013 and power unit 53190-SL0-A01 and on the 1995 the controller and power unit are all in one, so they are definitely not interchangeable . Some of the EPS controllers after 1995 may be compatible with the 1995 EPS. The controller did change after 1995; but, I can't remember when.

You can drive the car with the EPS controller disconnected.
Since you have already removed the controller, please let us know the last 3 digits of the parts no.
It is in the form of 33980-SL0-xxx.
If it's 95, most likely the last 3digits is -023, 305, etc.

EPS error code #22 is the famous one and most likely the burnt relay contact but it could be caused by the commutator issue inside the EPS rack, etc so keep in mind the possibility of multiple cause.

Unfortunately, the NSXCB server (nsxcb.co.uk) is down at the moment so can't point to the right blog category but there are lots of examples there.

If you are in US or nearby, just send the controller to BrianK here on Prime.
He is also on FB group.

Unfortunately, it won't be a plug&play between 91 and 95 EPS system.
91 has two separated boxes (controller + power unit) whereas the 95 is the single box solution (controller and power management in a single box) so connectors, loom, etc are all different.

Even with the single box solution on 95+ models, the EPS rack is also different depending on the year model so you need to be bit careful with the combination of the controller and the rack.

As long as you don't have any mechanical issues on the EPS rack, you can keep driving but at least, double check that the rack boots are not torn/split.
Otherwise, water can get inside and makes the issue even worse.

The first sign of the rack failure is the increased screeching noise but since you are new to NSX EPS system, probably you won’t know the 'out of factory' feeling/sound of it.
Very smooth, very little change in sound frequency while turning the wheel slowly and it's very quiet.