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Need Help Getting Codes P0412, P1641, & P1642

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Old 05-30-2006, 09:15 PM
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Default Need Help Getting Codes P0412, P1641, & P1642

Hey guys the other day i had these codes pop up on me. I have no clue what these coudl mean? I read soem forums and see that the P412 could be the air pump fuse but what do the other things mean? I will get back to you guys once i check that fuse.
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Old 05-30-2006, 09:28 PM
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P1642 is FC Relay 2 & 3, i have this same code. not sure of the others, but go to any parts store and the should scan it free and pull your codes and print them out for you.
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Old 05-30-2006, 09:34 PM
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P0412 Secondary Air Injection System Switching Valve A Circuit Malfunction

P1641 Malfunction Indicator Lamp (MIL) Control Circuit
P1642 Vehicle Speed Output Circuit
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Old 05-30-2006, 09:41 PM
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Ok well i checked the air pump fuse and that was indeed blown so replaced that but light still on. I went to autozone and did get the codes read and printed out. I am just trying to figure out what i need to do to fix them?
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Old 05-30-2006, 09:44 PM
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hey streetwarrior, i went to that same website a few months ago to retrieve my codes... that website is WAY wrong! i put my car on a tech II, a SnapOn modus, and a solus, AND a generic OBDII scanner, and all of them show P1642 as FC Relay 2 etc. Try putting the air pump relay in place of FC Relay 2 and see what that does.
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Old 05-30-2006, 09:48 PM
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So you think that relay might be bad? If i do that and it is that relay how will i know though? The light won't jsut shut off will it since i will have to remove the one relay.
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Old 05-30-2006, 09:48 PM
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Originally Posted by 96z28camaro
Ok well i checked the air pump fuse and that was indeed blown so replaced that but light still on. I went to autozone and did get the codes read and printed out. I am just trying to figure out what i need to do to fix them?

Disconnect the bat for 15 min the light should go away
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Old 05-30-2006, 09:56 PM
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Use this site to check codes

http://www.obdii.com/codes.asp
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Old 05-30-2006, 10:25 PM
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ok so i switched those relays liek you guys said to do and also disconnected my battery for 15 minutes and when i restarted no ses light was on but my question is are those codes, codes that reset right away or do they have to cycle thru a cycle before they kick the ses light back on.
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Old 05-30-2006, 11:24 PM
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Anyone else have a clue or have the same thing happen to them?
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Old 05-31-2006, 09:51 AM
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morning...ttt
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Old 04-08-2018, 01:40 PM
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Default lt1 overheat/parasitic draw

I have a similar problem on my 1996 Camaro LT1. After a couple misfires my check engine light came on the fuse to the fans was popped and so was the cigarette lighter slash data link connector fuse. I haven't checked for continuity at the fans yet but I switched a couple relays because the OBD2 was throwing codes p1641 and p1642. If the fan relays are good and the fans are good I'm thinking that I might have to change the optispark and while I'm at it the water pump and or the ECM. Let me know where you guys think thank you
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