wiring and relays for P75 to enable VTEC and IAB control

Hondata model coverage & ECU application questions.
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carnot
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wiring and relays for P75 to enable VTEC and IAB control

Post by carnot » Thu Jan 07, 2016 9:55 am

I understand that a P75 with the s300 system can be used to activate VTEC using one of the alternative outputs (A15 ACC, A20 PCS, A12 FANC, A16 ALTC) and an added relay. I have a few questions that hopefully someone can help me answer:

1. Does anyone have a specific relay that would be good to use and where to purchase?
2. Does the VTEC oil pressure switch need to be wired at all or can it be left disconnected and disabled in SManager?
3. Can one of the outputs listed above, with a similar relay, also be used to control the IAB?

Considering my vehicle still has AC, which output(s) would be best to use to control VTEC and the IAB? A20 and A16? What are the implications of not using the A20 PCS and A16 ALTC for their original intended output of actuating the Purge Control and Alternator Control respectively?

Thank you.

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Spunkster
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Thu Jan 07, 2016 2:09 pm

A standard relay that you find any just about any car audio/alarm shop will work.

You do not need the VTEC pressure switch if it is disabled.

If you look at the IAB settings on the VTEC tab of parameters you will see all the outputs you can use.

carnot
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by carnot » Fri Jan 08, 2016 6:21 am

Spunkster wrote:If you look at the IAB settings on the VTEC tab of parameters you will see all the outputs you can use.
Smanager lists more outputs than are indicated as available under the P75 ecu at this link, https://www.hondata.com/techvtecrelaydiagram.html .

Does this mean that the P75 does not have any real output on A10 or A17 and those are just listed for completeness because some other model ECUs do have the internal circuitry to use those output pins?

Thank you for the clarification.

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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Fri Jan 08, 2016 10:12 am

The options must be there for all ECUs. Some ECUs will not have the circuitry for these to work.

carnot
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by carnot » Mon Apr 18, 2016 10:28 am

Is a relay recommended/required when setting up IAB control? This is on an OBDI Prelude where ground(-) is the signal for actuating the IAB. In this case can a wire be directly run from the ECU to the ground wire of the plug on the IAB? Thank you.

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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Mon Apr 18, 2016 11:00 am

It says right in the parameters window you must use a relay for the IAB control using non-stock IAB output.

carnot
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by carnot » Mon Apr 18, 2016 1:19 pm

Is the diagram in the attached image the correct way to setup wiring for the IAB solenoid?
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Mon Apr 18, 2016 1:39 pm

I don't understand the fuse and the + to ECU, but the rest should work.

carnot
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by carnot » Tue Apr 19, 2016 5:07 am

The connector to the IAB solenoid has 2 wires and according the Honda Service manual one is power (+) obtained from the ECU power circuit (which has a 15A fuse as apart of that circuit) while the other is a ground (-) normally modulated by the ECU.

Hermanmax88
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Hermanmax88 » Tue Oct 09, 2018 1:56 pm

What will happen if you do not use a relay?

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Spunkster
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Tue Oct 09, 2018 3:17 pm

you will damage the ECU.

Hermanmax88
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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Hermanmax88 » Wed Oct 10, 2018 10:25 am

Damge the entire ecu? Or just the components that control that output?

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Re: wiring and relays for P75 to enable VTEC and IAB control

Post by Spunkster » Wed Oct 10, 2018 11:06 am

You must use a relay period.

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