Reason I ask, is I just had my rack rebuilt, and it feels great. I had Brian look at my EPS computer and he says it should be fine and could find nothing wrong. I continue to get an EPS light when I max out the steering to one side or another. Charles from NSX Rack Repair sent me a loaner EPS computer and it works fine. No EPS light ever. I guess I might have to buy one and was wondering since mine is a 94 Automatic, if I'm limited to specific production years. Thanks guys!!
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Are all EPS Computers interchangeable?
- Thread starter El-Cojonico
- Start date
Short answer - no. The early automatics with EPS had a separate power unit and control unit. By 1997, the power unit and control unit became a single device called the control unit. So, definitely the earliest EPS separate control and power units are not individually compatible with the later combined unit. I don't know when that design change occurred in the production run. However, it looks like your 1994 still has the separate power and control unit.
https://www.acuraoemparts.com/v-199...lectrical-exhaust-heater-fuel--control-unit-2
Was both your control unit and power unit checked out by Brian? On the later cars I know there were some problems with the power relays in the control unit. Kaz has discussed replacement of those relays on his blog. I think (but, don't know for sure) that those relays may be in the power unit in the early cars. If Brian only checked the control unit there may still be a problem with the power unit.
You might be able to interchange the units with the EPS from any early car (up to the design change). The tell would be checking the part numbers. It may also be possible to replace both the separate power and control unit in the early cars with the later combined control unit - that would require some wiring harness revisions (and advice from somebody who actually knows).
https://www.acuraoemparts.com/v-199...lectrical-exhaust-heater-fuel--control-unit-2
Was both your control unit and power unit checked out by Brian? On the later cars I know there were some problems with the power relays in the control unit. Kaz has discussed replacement of those relays on his blog. I think (but, don't know for sure) that those relays may be in the power unit in the early cars. If Brian only checked the control unit there may still be a problem with the power unit.
You might be able to interchange the units with the EPS from any early car (up to the design change). The tell would be checking the part numbers. It may also be possible to replace both the separate power and control unit in the early cars with the later combined control unit - that would require some wiring harness revisions (and advice from somebody who actually knows).
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Ok, so I need an EPS from a pre-97. I'm positive that it is the EPS not the power unit, since I swapped EPS's and have gotten no warning light. I did not swap power units. Brian is ending me back my old one. I will test it again, but if I get an EPS light, I'll be in the market for a computer.
Be careful with the cut-off date. I know for sure that the change in the EPS power / control units was in place by 1997; however, the change might have actually occurred when Honda added EPS to both the auto and manual NSXs in 1995. 1994 might be the last year of the separate control and power units.
The power units did not appear to change during the production run (up to the point that they were combined); but, the control unit did change, or at least got a revised part number. Up to 1992 the control unit part # ended in SL0-013 and for 1993 & 1994 it ended in SL0-000. The units might still have the same pin out arrangement so might be physically swappable; but, that does not guarantee that they will be 100% operation compatible. When you did your test swap of the control unit, were the parts numbers identical?
The power units did not appear to change during the production run (up to the point that they were combined); but, the control unit did change, or at least got a revised part number. Up to 1992 the control unit part # ended in SL0-013 and for 1993 & 1994 it ended in SL0-000. The units might still have the same pin out arrangement so might be physically swappable; but, that does not guarantee that they will be 100% operation compatible. When you did your test swap of the control unit, were the parts numbers identical?
I'm currently using the swapped unit. The part number ends in SLO-A01 and its working like a champ.
Check your complete part number; but, it sounds like you swapped out the EPS power unit, not the control unit. 53190-SL0-A01 is the power unit, not the control unit. 39980-SL0-A00 is the control unit on the 1994 cars and just to confuse things the parts site refers to it as the EPS unit as opposed to the EPS Control Unit. To doubly confuse things, the early EPS power unit (39980-SL0-A00) looks quite a bit like the combined EPS unit used on the later cars.
Your absolutely right, the complete part number is 53190-sl0-a01 on the unit. Which Acura calls it a Power Unit. So..that being identified. I'm still stuck only getting ballpark pre-97. Correct? Either way. My original Power Unit is coming back from Brian. He couldn't ID the problem. The swapped one is working.....
Yes, it looks like you are stuck sourcing a replacement power unit from a pre 1995 car (according to the parts catalog).
Since your EPS light comes on when the rack runs up against the limits on the right or left side, it sounds like the error condition might be caused by the rack motor exceeding the current limits within the control unit. The current sensor is in the power unit, not the control unit which is why switching the power unit may be fixing the problem - if the problem is with the current sensor. The current sensor could be a solid state device or it could be as simple as a shunt resistor with the control unit monitoring the voltage drop across the shunt. More voltage drop meaning more current. 'If' the current sensor is a simple shunt, heating caused by the motor current may have caused deterioration of the solder joints meaning a higher effective resistance for the shunt. The higher resistance will cause a higher sensor output voltage for the same current which may exceed the error setting in the control unit. It is possible that you could have this 'drift' in the sensor; but, the sensor still tests out OK. If Brian K checked over your EPS Power Unit and couldn't find a problem, it might be worthwhile asking him whether he was able to check and confirm the calibration of the current sensor.
Since your EPS light comes on when the rack runs up against the limits on the right or left side, it sounds like the error condition might be caused by the rack motor exceeding the current limits within the control unit. The current sensor is in the power unit, not the control unit which is why switching the power unit may be fixing the problem - if the problem is with the current sensor. The current sensor could be a solid state device or it could be as simple as a shunt resistor with the control unit monitoring the voltage drop across the shunt. More voltage drop meaning more current. 'If' the current sensor is a simple shunt, heating caused by the motor current may have caused deterioration of the solder joints meaning a higher effective resistance for the shunt. The higher resistance will cause a higher sensor output voltage for the same current which may exceed the error setting in the control unit. It is possible that you could have this 'drift' in the sensor; but, the sensor still tests out OK. If Brian K checked over your EPS Power Unit and couldn't find a problem, it might be worthwhile asking him whether he was able to check and confirm the calibration of the current sensor.
The part is on its way back, so at this point it either works or doesn't. My money is on doesn't. So hopefully someone has one laying around and sells it for cheap.
Might be worth checking with Kaz- he might be able to diagnose it for you.
Good idea.
Eps
My EPS unit failed. I sent it to Brian and it he was unable to fix it. I sent it off to APX engine repair in Jacksonville, FL. They guaranteed that they could fix it. After $550 and two return trips to them, it still would not work. I ended up buying a new unit from Delray Acura for $1,600. APX would not refund my money and refused to answer my emails and calls. I ended up backing out the transaction with American Express. If there is someone who can rebuild these units? Lastly, don't use APX for anything. Jerry
My EPS unit failed. I sent it to Brian and it he was unable to fix it. I sent it off to APX engine repair in Jacksonville, FL. They guaranteed that they could fix it. After $550 and two return trips to them, it still would not work. I ended up buying a new unit from Delray Acura for $1,600. APX would not refund my money and refused to answer my emails and calls. I ended up backing out the transaction with American Express. If there is someone who can rebuild these units? Lastly, don't use APX for anything. Jerry
Good to know Jerry. I'm sending my computer to the guys at rack repair. They said they might be able to fix it. If not I'll be hunting for a used one.
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