Which wire for '90 B18A1 is constant ECU power for OBD0?
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Honda-Tech Member
Joined: Oct 2004
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From: VA, USA
Which wire for '90 B18A1 is constant ECU power for OBD0?
I keep looking at the pinouts, diagrams and everything else on the site for PR4 ecu's but can't decipher which is the hot wire for the ECU that I need. My problem is the ECU doesn't remember anything and seems to not have constant power. My ECU fuse under the hood is good as well as all my others. Is the wire in in Plug A, B or C? Any help guys?
Old Fart
Joined: May 2004
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From: kelowna, bc, canada
Re: Which wire for '90 B18A1 is constant ECU power for OBD0?
It is the white/yellow, [or white/green] fuse 34-7.5A USDM and 10A CDM, in engine bay fuse box.
It is the only white/yellow or white/green lead going to the ECU/ECM so should not be hard to find, [my Haynes does not give a pin-out].
How did you check the fuses, did you test them in the fuse box or just pull and eyeball them?
Best way is to use a 12V test light, [not the LED type] and touch the probe to both "test tips" on the fuse with the fuse installed in the fuse box. 94
It is the only white/yellow or white/green lead going to the ECU/ECM so should not be hard to find, [my Haynes does not give a pin-out].
How did you check the fuses, did you test them in the fuse box or just pull and eyeball them?
Best way is to use a 12V test light, [not the LED type] and touch the probe to both "test tips" on the fuse with the fuse installed in the fuse box. 94
Thread Starter
Honda-Tech Member
Joined: Oct 2004
Posts: 555
Likes: 1
From: VA, USA
Re: Which wire for '90 B18A1 is constant ECU power for OBD0?
It was indeed the white/green wire as backup for the ECU. Ran a power line and all is good now! Thanks for the help again FCM! You rock dude!
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hatchinprogress
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May 2, 2006 10:52 AM