Electric Power Steering with no CAN - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

ML · 10-21-2021, 08:10 PM

Does anyone know if you our EPS motor will run in limp mode with only power and no CAN connection? Context is this is a aftermarket ECU and I'm building the chassis harness and would rather not run add the complexity of steering angle sensor, so just want to give the EPS motor/controller 12v and be done.

pope · 10-22-2021, 02:15 PM

I read in another thread (I don't remember which) that it does similar to the Prius, but I cannot confirm at the moment. Although, I did recently acquire the parts to experiment with, but haven't done so yet.

ML · 10-22-2021, 02:22 PM

Quote:

Originally Posted by pope

I read in another thread (I don't remember which) that it does similar to the Prius, but I cannot confirm at the moment. Although, I did recently acquire the parts to experiment with, but haven't done so yet.

That is very much what I'm hoping and is my guess just based on visual similarities between ours and the Prius'.

pope · 10-22-2021, 11:25 PM

I found a fail safe chart in the service manual this evening. I highlighted the condition I believe it will operate in when missing the CAN data (speed) from the stability computer. We should have a continuous output roughly equivalent to highway speeds.

ML · 10-23-2021, 08:06 AM

Wow you are awesome! Send me your PayPal and I’ll throw you some beer money!

pope · 10-23-2021, 10:43 AM

Not necessary. I was going through the manual looking for a wiring diagram and stumbled on the chart.

Franklin. · 03-10-2023, 06:14 AM

Were you able to find a remedy to this? I swapped in a 2JZ and want to run as much of the car as possible on the standalone ecu.

If there's a way to permanently limit the power steering without the body control & power steering modules id love to hear how if worked out in your case.

ML · 03-10-2023, 08:41 AM

Quote:

Originally Posted by Franklin.

Were you able to find a remedy to this? I swapped in a 2JZ and want to run as much of the car as possible on the standalone ecu.

If there's a way to permanently limit the power steering without the body control & power steering modules id love to hear how if worked out in your case.

yes, you just give the PS box 12v straight from the battery and ground with the 4ga wire, and then switched 12v to the box on pin 6 of connector a15 to switch it on. it will go on limp mode but I have found it to be perfectly adequate that way

Franklin. · 03-12-2023, 12:51 AM

Quote:

Originally Posted by ML

yes, you just give the PS box 12v straight from the battery and ground with the 4ga wire, and then switched 12v to the box on pin 6 of connector a15 to switch it on. it will go on limp mode but I have found it to be perfectly adequate that way

That makes sense.
Does the power steering box need the other modules in place to have the ability to go into limp mode?
I deleted ABS, and I'm not sure if the box needs inputs from the wheel speed sensors or if I can delete the system all together.

ML · 03-12-2023, 12:51 PM

Quote:

Originally Posted by Franklin.

That makes sense.
Does the power steering box need the other modules in place to have the ability to go into limp mode?
I deleted ABS, and I'm not sure if the box needs inputs from the wheel speed sensors or if I can delete the system all together.

no, I have mine in with an engine swap and a standalone ECU and no ABS and its fine.

10-22-2021, 11:25 PM	#4
pope has a funny hat Join Date: Feb 2020 Drives: 2014 BRZ Limited Location: MI Posts: 480 Thanks: 1,022 Thanked 613 Times in 271 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	I found a fail safe chart in the service manual this evening. I highlighted the condition I believe it will operate in when missing the CAN data (speed) from the stability computer. We should have a continuous output roughly equivalent to highway speeds. Attached Images Last edited by pope; 10-23-2021 at 10:43 AM. Reason: Spelling

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10-22-2021, 02:15 PM	#2
pope has a funny hat Join Date: Feb 2020 Drives: 2014 BRZ Limited Location: MI Posts: 480 Thanks: 1,022 Thanked 613 Times in 271 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	I read in another thread (I don't remember which) that it does similar to the Prius, but I cannot confirm at the moment. Although, I did recently acquire the parts to experiment with, but haven't done so yet.

10-23-2021, 10:43 AM	#6
pope has a funny hat Join Date: Feb 2020 Drives: 2014 BRZ Limited Location: MI Posts: 480 Thanks: 1,022 Thanked 613 Times in 271 Posts Mentioned: 9 Post(s) Tagged: 0 Thread(s)	Not necessary. I was going through the manual looking for a wiring diagram and stumbled on the chart.

03-10-2023, 06:14 AM	#7
Franklin. Member Join Date: Jan 2017 Drives: 2013 Brz Limited Location: SoCal Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Were you able to find a remedy to this? I swapped in a 2JZ and want to run as much of the car as possible on the standalone ecu. If there's a way to permanently limit the power steering without the body control & power steering modules id love to hear how if worked out in your case.

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