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-   -   dtc's on obd2 Need help understanding. (

krruzer 04-21-2008 04:13 PM

dtc's on obd2 Need help understanding.
I have just finished a 37 ford fiberglass street rod with a 6 liter engine and automatic trans.out of a 06 GTO 6000 miles. The wiring harness is from street and performance. The computer has also been reworked by them. My question is, I have a check engine light on and after scanning the trouble codes one being po174 system to lean. (Possible fuel injector restriction ) The second code po690 has me stumped ecm/pcm power relay, sense circuit Hi. If anyone can shed some light on this I would appreciate the feed back.

sharpe427 04-21-2008 08:41 PM

The lean code would more than likely be a vacuum leak somewhere. The 690 code is sensing the voltage input to the ECM power circuit is too high...make sure that the oe GTO circuit did not reduce input to the ecm (not run 13.8-14.1V straight off the alternator). An understanding garage or friend would be able to get you a spec sheet and wiring diagram.

carsavvycook 04-21-2008 09:41 PM

p0690 is set when the ecm detects voltage with the switch is off, this being from the relay feedback circuit(pin 86 if I remember). The brown wire at the relay is the wire the computer commands off. Check it for power with the key off.

krruzer 04-23-2008 01:39 PM

This aftermarket wiring harness comes with a 8 panel fuse block and has two relays to my knowledge. One for the electrical fuel pump and the other is a starter relay. I also ,wanted to mention this also has a ez wire fuse panel. Thanks for your help.

krruzer 04-23-2008 03:12 PM

Update on dtc690, spoke to the programmer about this and he states that the original wiring harness had a relay, however, they just turn this circuit off when they reprogram the computer for there harness. He states this won't cause any problems to the computer.

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