91 NSX with Trouble Code 12

[Jin1976]

I've jump the Service Check Connector and got code 12 with one blip and a long pause followed by two quick blips. It's code for EGR failure. Do I need to repair or replace the throttle body? Also when jumping this connector the TCS light is also flashing.

 

[Daedalus]

Could be something really simple, like a broken vacuum hose. Look at the vacuum hose going to the EGR and look for disconnects and/or cracks. If you have a vacuum gauge/pump you can test the operation of the EGR manually and make sure it works/isn't clogged. Could be the vacuum solenoid or lift sensor too.

 

[Jin1976]

Thank you D. Will get the EGR clean first and will also check on the other two.

 

[zahntech]

The code is for the lift sensor...cleaning the ports will have no effect..as the computer is noting an open or short in that circuit.

 

[Jin1976]

Would that mean I need to replace the EGR valve lift sensor? If so how much would it be? Would that be the same as the other Honda car incase the dealer don't have the NSX's one in stock? Thanks.

The code is for the lift sensor...cleaning the ports will have no effect..as the computer is noting an open or short in that circuit.

 

[zahntech]

You should go thru the Diag procedure for code 12 before replacing the egr valve/lift sensor....

The part # is 18011-PR7-A00..I have not found anyother honda that uses it.

 

[Jin1976]

Sent the car to my old trustworthy mechanic. He did all the procedure going with the code 12. Non of the items are defective. He heard rattle under the intake manifold cover. Turns out the recent mechanic had tempered with the two yellow painted screw located under the throttle body. As my mechanic said today those screw should not be touched as they have been calibrated to control the opening of the six intake holes. It will take him about two days to work on the car because day time he has to do his job in another workshop (he's helping me as a friend). He also said that the previous mechanic may do damage on the t-belt when he retightened it for the second time. I just hope this will be the last fix on my car for a long duration.