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IAT Voltage ?

Posted: Sun Oct 09, 2016 6:22 am
by Andrewmark
hi guys hope somebody can help.....
ive got a yr 2000 mb6 vti, (b18c4)
my s300 is showing an error code, it wont run properly & ive been unable to fix it :(
the s300 is showing the IAT as the fault, ive changed the sensor twice now, so all three sensors cant be wrong.
so ive taken the plug off the sensor (2 wires, red/yellow & green/blk) the green/blk has 14v and the red/yellow reads 5v.....is this correct ???
still leaving the IAT plug disconnected with the motor running, the voltage coming OUT of the S300 Ecu on the red/yellow wire is 5v but i dont know where to green/black wire goes too.
Anybody got any clues as to what is going on ???
I thought 5v should go into the IAT sensor and depending on the temperature is should have less than 5v out the other side & back into the ecu so it can adjust fuelling ???.

Re: IAT Voltage ?

Posted: Mon Oct 10, 2016 8:19 am
by Hondata
5V on the IAT wire is normal but the other wire should be logic ground.

Are you sure that the IAT and IACV were not switched at some point? That tends to damage things.

Re: IAT Voltage ?

Posted: Mon Oct 10, 2016 2:11 pm
by Andrewmark
thanks for the answer/reply
ill get my electrical guy to check it out :)

Re: IAT Voltage ?

Posted: Sat Oct 15, 2016 10:30 am
by Andrewmark
hi all......
ok so the sideof the IAT sensor plug that should be a logic ground (green/black wire) has 14v !, thats definatly not right.......
so ive stripped back the loom a bit and found that that wire has been joined to a plain green wire that has 14v ! (i didnt do it) an ' auto electrical' guy that obviously was not competent did.
I cannot see where it was previously joined to, so my question is..... does anybody know where that wire should go to ???
ive got the usuall pdf manual but cant make sense of the diagram :(

Re: IAT Voltage ?

Posted: Sat Oct 15, 2016 12:44 pm
by Andrewmark
ok so ive looked hard at the wiring diagram and narrowed the problem down......
the green/black wire in question should be a 'logic ground' there are only 2 'logic grounds on the ECU pins,
According to the scanned pic below.... connectors... A26 = LG1 & connector B2 = LG2 (which i think could be the right one) on the picture it says (SG2) ???
Anyone got any ideas befor i go and splice them together to try them with the S300 plugged in on the sensor tab to check ???
civic wiring scan.pdf

Re: IAT Voltage ?

Posted: Sun Oct 16, 2016 12:46 pm
by Andrewmark
Update......
All fixed now :)
the wires from the IAT sensor are red/yellow which is joined to 'D' connector number 15 & the green/black wire (logic ground) is joined to 'D' connector number 22 :)
hope this may help somebody else ......