Question : PCS on OBD1/OBD0

Hondata model coverage & ECU application questions.
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Question : PCS on OBD1/OBD0

Post by WongKN » Sun Nov 16, 2008 9:06 pm

I have a question about PCS which I hope someone can help me answer here. I am using an OBD1 P30 ECU with S300 on an OBD0 vehicle (91 Integra) with a conversion harness. I am finding an unexpected connection in the conversion harness regarding the PCS pin/wire.

Basically the conversion harness connects the OBD1 A20 wire/pin which is for PCS / EVAP purge control solenoid to A6 wire/pin on the OBD0 harness (note : mine is pure JDM). However pin A6 is empty (unused) on the OBD0 harness. On the other hand, pin A10 on the OBD0 harness is used for 'PCS Purge Valve' according to the PR3 harness infor here on After doing some research on the net, I found a reference which actually lists two different uses for pins A6 and A10 on OBD0 harness as follows:

A6 = Purge Cut-Off Solenoid
A10 = Pressure Regulator Cut-Off Solenoid valve.

So my question is what are the differences between the 2 and what is the equivalent on the OBD0 harness to pin A20 on the OBD1 harness ? I.e. as A6 is unused on my harness while A10 has no connection to the OBD1 ECU, should I join B20 to A10 instead of A6, or are A6 and A10 totally different things altogether ?

Again, note my Integra is JDM 1991 DA6 Honda Integra XSi (with the 1G B16A engine). And I am using a JDM P30 (2G B16A) ECU with Hondata S300. So some of the information on the net seems may not apply to me. Hopefully someone knows the answer.

Many thanks in advance.
Best Regards,
(yes, of TOVA).

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Post by Spunkster » Mon Nov 17, 2008 11:03 am

Since most OBD0 adapters are intended for US vehicles, they are setup for a US vehicle wiring. THE PW0/PR3 was never sold in the US. Modify your harness using the info at: