Can't clear p1518 code

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Jun 16, 2015 | 01:07 AM

#21

RXPX

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Joined: Jun 2015

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Quote:

Originally Posted by madmatt9471

What was the cause of yours?

This definitely can help!

Thanks,Matt

I think what he was basically saying is, the cause of his problems was a weak battery.

Hey Matt, you seem pretty knowledgeable, you mind taking a look at my thread. I'm hoping I could get Bill on track also.

To the OP, I'm having some slightly similar issues to you. As far as getting your car to at least run, try slowly cycling through the ignition positions. When you get to the 'ON' spot, let the pump prime, then go ahead and start the car. Also, try your cooling fan relay in place of your ignition relay. They should be the same part number '3604'.

Hope this helps. If you do figure out your problem please be sure to update the thread to help out anyone else who might run into this problem.

Feb 16, 2019 | 07:32 PM

#22

weinerschizel

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From: Stillwater Minnesota

My 99 vette will not start, it cranks but doesn't turn over. I scan for codes and get P1518. Curious are their relays and or fuses on this circuit, I have no wiring diagrams for this car

My battery voltage is at 13.6V (its a sealed battery) wondering if that could cause issue? Although battery has never caused issue before.

Feb 17, 2019 | 06:06 PM

#23

sabastian458

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From: Easley/Anderson South Carolina

I had to replace my throttle body to fix mine. Would randomly set p1516, p1517, and p1518. Would spin starter but not fire off.

Feb 17, 2019 | 07:19 PM

#24

bighank

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From: Silver Spring MD

I had this problem for 2 months-was the Ignition Switch

Had the P1518 code for 2+ months, Car would crank but not start, Checked wires from Accelerator to TAC to PCM to TPS to TB motor. No opens or shorts. Replaced TAC, no change.

FINALLY replaced Ignition Switch (just the back electrical part as the lock cylinder and VATS sensor was OK) . Car started right up. Its FUN to pull the car apart to get to the switch but was the answer. If you really need a TAC let me know as I have a good one gathering dust.

Feb 17, 2019 | 11:58 PM

#25

weinerschizel

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From: Stillwater Minnesota

Quote:

Originally Posted by bighank

Many thanks. I need to find time to test the electrical connections and grounds as the post suggests then will let you know. I really appreciate it. This actually make take me several months.. :/

Feb 18, 2019 | 09:21 AM

#26

C5 Diag

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Joined: Sep 2013

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From: Cape Coral, Florida

Quote:

Originally Posted by weinerschizel

My 99 vette will not start, it cranks but doesn't turn over. I scan for codes and get P1518. Curious are their relays and or fuses on this circuit, I have no wiring diagrams for this car

My battery voltage is at 13.6V (its a sealed battery) wondering if that could cause issue? Although battery has never caused issue before.

To determine if your P1518 is related to a bad ignition switch ( the TAC module is very fussy about the voltage it receives) is to do a “voltage drop” test across the switch. Using a multi meter with the red lead connected to the positive post of the battery and the black lead connected to one of the 2 test points on top of Fuse 16 (PCM) CRANK THE ENGINE OVER....you should not read MORE than .3 volts !!

Mar 16, 2019 | 04:59 PM

#27

weinerschizel

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From: Stillwater Minnesota

I need somebody yet to help me crank the engine while I watch the MultiMeter.

I did go into clean up some grounds though. My ground to engine was not even registering, it was showing as an open.It was a simple fix, I took apart those ground connectors and cleaned those too. I only did three of the grounds where connects to frame rails in engine bay. I also checked block and alternator after and all the grounds in engine bay are good now (I think).

I disconnected the TAC, and checked to see if the black wire goes to ground. I got nothing. Is that correct? I tested other wire too just to see. It also showed no connection to ground. Shouldn't one side of the TAC connector be ground? Or is it electrically isolated?

Mar 18, 2019 | 08:50 PM

#28

weinerschizel

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From: Stillwater Minnesota

Okay I'm stupid, really stupid. I disabled my Corvette months ago so it wouldn't start. Say if somebody tried to steal it. Then well *ahem* I forgot I'd done that. Once I put the ignition relay back in place it worked fine (now you know my anti theft process lol). Perhaps of use to somebody to know a bad ignition relay will also trip a P1518 code.