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Another "Code" Thread (51 to be precise)
Posted: Mon Aug 17, 2009 6:05 am
by asc_up
Well I went to reset my ECU today after changing my spark plugs and O2 sensor and as I was driving around trying to get the ECU to clear, code 51 popped up and it won't go away.
51 is either the neutral switch or the inhibitor switch, or it could possibly be both. How do I go about fixing this problem so I can properly clear my ECU?
This is on the 91 SS 5MT.
Posted: Mon Aug 17, 2009 8:14 am
by BSOD2600
Page 2-7c / 102 of the FSM Josh posted

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Basically check voltage between ECU and body. check neutral switch. Check harness connector between ECU and neutral switch. Repair ECU terminal poor contact...
Posted: Mon Aug 17, 2009 8:24 am
by asc_up
Awesome. Thanks dude!
Posted: Mon Aug 17, 2009 6:19 pm
by asc_up
Well, that was easy!
For anyone who cares lol: About a month ago I found a small nut on the drivers side footwell. I was going to toss it, but instead decided to keep it around in case I found what it went to. Well, I found what it went to! Haha. It was one of the nuts that held on the ECU.
I replaced it and after that, code 51 is no more. It also helped aleviate some idling issues that I was having.
Thanks again for your help, BSOD.
Posted: Mon Aug 17, 2009 6:24 pm
by wtdash
asc_up wrote:Well, that was easy!
For anyone who cares lol: About a month ago I found a small nut on the drivers side footwell. I was going to toss it, but instead decided to keep it around in case I found what it went to. Well, I found what it went to! Haha. It was one of the nuts that held on the ECU.
I replaced it and after that, code 51 is no more. It also helped aleviate some idling issues that I was having.
Thanks again for your help, BSOD.
This was one of the 2 that hold the ECU to its tray? So, probably a ground issue?
I've had the 51 code on occasion and idle issue, so it may be relevant (and I've the EcU out about 100 times w/the Revtronix chip testing I've done!).
Thanks
Posted: Mon Aug 17, 2009 6:30 pm
by asc_up
Yep, it was the top nut to be exact. You are correct about it being a ground issue as well. All the testing that the FSM calls for is about checking for ground/voltage between the ECU and chassis.
I'm also positive that's why mine fell off, I must not have torqued it back down after I installed the chip.