No Check Engine Light when switch is open ?
#1
No Check Engine Light when switch is open ?
I already posted this once but I lost my other phone with my login info but anyways trying to smog my car but it wont pass due to a functional test obd port doesnt work and check engine light does not turn on when i open the switch. i checked the dash and it gets + but not - atleast thats my conclusion i bought a multimeter but cant figure out how to use it anyways i went to the computer to see if anything was up there and it looks like the wires there have been modified ( i will post a picture down below) so now i need your guys help ... any info would be great thanks !
#3
Thanks for your post.
I looked at your photos and did not see where anything was 'modified' unless you mean the maybe-by-hand-wire-splices I maybe see. Hard to know why anyone would do that unless you can check each of those wires to its end point at the ECU and figure out what signal they were supposed to carry.
I have seen diagrams that can trace every input and output at the ECU and, yeah, takes a genius or definitely someone with no attention span deficits to follow them. At this point, you could use a circuit tester instead of a multi-meter. Turn ignition on and see if every input/output at your ECU is live (getting/giving a signal). Your circuit tester should light up and beep. Dead circuits don't.
Your quickest maybe-fix would be find another harness section (recycled?) for the one in your fotos and swap it in to see what operates differently after the swap. There are no short cuts when POs start messing with your electronics and then leave their mess behind. They never tell you what or why...
PS: States that rely on the car's own electronics for pass/fail emissions tests are real boneheads. Just test what comes out of the dang exhaust at various RPMs/speeds. It 'pollutes' or it 'passes.' What's the big deal with electronics, esp on older models?
I looked at your photos and did not see where anything was 'modified' unless you mean the maybe-by-hand-wire-splices I maybe see. Hard to know why anyone would do that unless you can check each of those wires to its end point at the ECU and figure out what signal they were supposed to carry.
I have seen diagrams that can trace every input and output at the ECU and, yeah, takes a genius or definitely someone with no attention span deficits to follow them. At this point, you could use a circuit tester instead of a multi-meter. Turn ignition on and see if every input/output at your ECU is live (getting/giving a signal). Your circuit tester should light up and beep. Dead circuits don't.
Your quickest maybe-fix would be find another harness section (recycled?) for the one in your fotos and swap it in to see what operates differently after the swap. There are no short cuts when POs start messing with your electronics and then leave their mess behind. They never tell you what or why...
PS: States that rely on the car's own electronics for pass/fail emissions tests are real boneheads. Just test what comes out of the dang exhaust at various RPMs/speeds. It 'pollutes' or it 'passes.' What's the big deal with electronics, esp on older models?
Last edited by zxguy1986; 05-04-2015 at 06:53 PM.
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