Code 1518
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From: Cape Coral, Florida
I'd clear the DTC and see if it comes back. P1518 can set if battery voltage is low. Also check that "THROT CONT" fuse is good and is powered and then I'd probably disconnect the TAC module harness and check the wiring down there... You can start there !!
Last edited by C5 Diag; Dec 12, 2018 at 11:48 AM.
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From: Cape Coral, Florida
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,669
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From: Cape Coral, Florida
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Pro
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So if fuse, power and ground are good to the module then it's "most" likely the module. If the fuse is popped I have a short to ground on the pink wire leading to the module? Reason I ask is the yellow and brown wire from the throttle body are routing under it. If suppose one of those touched ground would the fuse blow? Thanks.
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Joined: Sep 2013
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From: Cape Coral, Florida
Yes, if the pink wire that goes from the THROT CONT (17) fuse to the TAC Module is shorted to ground the fuse will blow. With the ignition OFF do you have voltage at the fuse ??...(if so that pink wire is shorted to power somewhere and will set the DTC)...you should only have power there with key ON or START. I'm assuming the brown and yellow wire you are taking about is the TAC motor ??...I don't have an FSM wiring diagram in front of me but if I can remember that DTC will set if there is a short to voltage on the TAC Module ground circuit too...it's probably a black or black/white wire. You can also have some wiring issues at the TAC motor also. Sorry I can't give you more help right now. Before you fire the parts canon I'd check the wiring.
Last edited by C5 Diag; Dec 12, 2018 at 09:35 PM.
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Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
Now that I'm thinking about it I had starting issues with my own '01 about 2 months ago...was a P1518 and I also had a R.E.P. and "low voltage" on the DIC which I knew was false. My battery and charging system are fine. My first thought was a bad ignition switch so I cycled the key a bunch of times thinking there was some corrosion on the ignition contacts...car started fine after that and couldn't duplicate the problem. Changed the switch and everything is OK now...did the car "cut out" while driving ??...that too can be a bad ignition switch !!
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Thanks to rwobs for the troubleshooting help found the tac motor wires, yellow and brown, were routed under the snout of the intake. The yellow rubbed on the steam pipe which caused the short I was after. Fixed harness and re routed wires and all good now.
Melting Slicks
Joined: Jul 2006
Posts: 2,332
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From: Silver Spring MD
Mine was a bad igniton switch... Have a extra TAC if you need one
Went thru hell testing all leads from TAC to TB, PCM, and accelerator pedal. NO DICE. Ordered a TAC and replaced it. NO CHANGE. Car world crank but not start and produced a P1518 code every time. Replaced Ignition Switch (rear part only D1499C) and car started. If you need a TAC I have one gathering dust.
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