I really NEED HELP!!!!!
Former Vendor
Joined: Mar 2003
Posts: 18,666
Likes: 395
From: Tampa FL
St. Jude Donor '07-'08-'09-'10-'11-'12'-'13-'14-'15
I had the same thing after car sat for awhile while I was deployed. I put a new optima red top 34/78 in it and it quit. I do have a new red top 34/78 for sale if you are interested. It is brand new in the shrink wrap. PM sent
Cajun
Cajun
Thread Starter
Instructor
Joined: Feb 2006
Posts: 139
Likes: 0
thanks guys but I put a new battery in it and did NOT solve the problem, I cleaned all the grounds in the engine compartment and still no fix. I found my ground strap from the block to the frame on the driverside was loose, but cleaning and tightening it did nothing to solve the problem. I did notice while i was under the car that the rear passenger rear O2 wire was melted on the header, so maybe that could be the problem. Thats the only things left!!!!
not sure what else to do.....
not sure what else to do.....
Heel & Toe
Joined: Jul 2008
Posts: 22
Likes: 0
From: Madrid
Hi
I´ve read this post and i remember...
I suffered the same problem:
Low Voltage
Check engine
Reduced Engine Power...
I checked battery... terminal...cables... fuses...grounds...BCM...
and finally i checked the ignition switch, eureka!!!
Burned contacts
I followed one post of Bill Curlee to check and mend the switch (i don´t remember the link, but you can look for it with the search menu upside) and had no problem... very easy
Hope it´ll be helpful
I´ve read this post and i remember...
I suffered the same problem:
Low Voltage
Check engine
Reduced Engine Power...
I checked battery... terminal...cables... fuses...grounds...BCM...
and finally i checked the ignition switch, eureka!!!
Burned contacts
I followed one post of Bill Curlee to check and mend the switch (i don´t remember the link, but you can look for it with the search menu upside) and had no problem... very easy
Hope it´ll be helpful
Racer
Joined: Nov 2008
Posts: 412
Likes: 1
From: Lampasas Texas
Ignition switch is a good ideal to check. I had not heard about that and thanks for the information. Post title is: "C5 Ignition Switch Repair"
Foot note on the grounds:
Bill Curlee's post "Important Electrical Information"; I think that the car has 16 grounds. Bill included good information and pictures on his post as to the location of them all. It would be good Preventative Maintenance to check, clean, and use dielectric grease on all of them. That little bit of PM will help you for a long time to come. That is exactly what I am doing today with my car.
Good luck
Foot note on the grounds:
Bill Curlee's post "Important Electrical Information"; I think that the car has 16 grounds. Bill included good information and pictures on his post as to the location of them all. It would be good Preventative Maintenance to check, clean, and use dielectric grease on all of them. That little bit of PM will help you for a long time to come. That is exactly what I am doing today with my car.
Good luck
Last edited by Boulty1961; Dec 7, 2008 at 11:31 AM. Reason: added Ignition Switch Repair post name
Thread Starter
Instructor
Joined: Feb 2006
Posts: 139
Likes: 0
Thanks guys, Ill check the ignition switch..... I took care of all the grounds under the hood minus the one on the back of the driverside head. So I guess I do that one and check the ignition switch!!! Thanks guys, I feel like Im losing my mind!
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Racer
Joined: Nov 2008
Posts: 412
Likes: 1
From: Lampasas Texas
Don't give up. It is a labor of love. I do love to drive but I also like working on it and learning more each time. Just keep looking and you will find it.
P.S. I am going to go outside now and work on mine for a while. I have got a small code issue myself.
P.S. I am going to go outside now and work on mine for a while. I have got a small code issue myself.
Drifting
Joined: Aug 2007
Posts: 1,969
Likes: 8
From: Champaign IL
Sorry, I just Tuned in.. YES I too think it's your ignition switch. You have the same Codes I did when It was MY ignition Switch, Plus your cars acting the Same Way. Here's the Fix...
http://forums.corvetteforum.com/c5-t...ch-repair.html
http://forums.corvetteforum.com/c5-t...ch-repair.html
Thread Starter
Instructor
Joined: Feb 2006
Posts: 139
Likes: 0
Im so dumbfounded as to what is wrong with my pile that I dont know what to do???? I removed the ignition switch and found the tabs to be burned up just as the ones in bills write up. I cleaned everything just as he did, reassembled everything and still have the same problem!!!!
I did have to put the jump box on the battery because I had left the over head lights on in the interior from last time ...so the battery was completely drained.
SOMEONE PLEASE HELP!!!!
I did have to put the jump box on the battery because I had left the over head lights on in the interior from last time ...so the battery was completely drained.
SOMEONE PLEASE HELP!!!!
Melting Slicks
Joined: Oct 2007
Posts: 2,383
Likes: 13
From: Kinston North Carolina
We know you are frustrated by now, this has been going on too long. I just did a search for "P1518", and there is a lot of reading on it. No garantee on my thoughts, but to me, seems that MIGHT be some of your problems. Do you have correct service manuals for your car. If not, search for P1518, and read, read, read. In the meantime, maybe someone here can post the section of the manual that deals with the TAC module communication problem. This might not be your problem, if not, you can just blame me for wasting your time, ok? HTH, BH
Safety Car
Joined: May 2004
Posts: 4,811
Likes: 2
From: Simpsonville SC
I must be lucky, my car sits for long periods of time more than 14+ days and It starts everytime. Yea I have new battery, but I will check the battery if this ever happens to me. Good Luck man on getting her fixed!
Last edited by happa; Dec 12, 2008 at 12:33 AM.
Tech Contributor
Joined: Oct 1999
Posts: 40,995
Likes: 9,759
From: Charlotte, NC (formerly Endicott, NY)
A couple of things to check when you have P1518:
The following may cause an intermittent:
The diagnostic procedure for P1518 has 23 steps of which I posted some of the more obvious things to check. If you need the complete procedure I can provide.
Bill
- DTC P1518 sets if the battery voltage is low. If the customers concern is slow cranking or no crank because battery voltage is low, ignore DTC P1518. Clear any DTCs from memory that may have set from the low battery voltage condition.
- Check the Throt Cont fuse.
- DTC P1518 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the circuits that are in the TAC module harness (i.e. cruise, brake). An inspection of the fuses may lead you to the circuit that is shorted to the TAC module ground circuit.
- Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
The following may cause an intermittent:
- Poor connections. Check for adequate terminal tension. Refer to Body and Accessories/Wiring Systems for proper procedure.
- Corrosion
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
- Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs should be set and no circuit or component problems can be located.
- For an intermittent condition refer to Symptoms .
- If a repair is completed and the DTC was cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred.
- When the TAC module detects a problem within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.
The diagnostic procedure for P1518 has 23 steps of which I posted some of the more obvious things to check. If you need the complete procedure I can provide.
Bill
Advanced
Joined: Mar 2007
Posts: 90
Likes: 2
From: San Antonio Texas
98 C5 A4 - DTC P1518 - Code Too Help!!!
This post was very helpful I too have a DTC P1518 Code but the car won't move! The car starts but revs at 1800 RPMs and the reduce power, traction control light comes one...basically the computer is screaming at me telling me I have a problem plus the gas peddal does not respond.
Things I have done so far:
a. Checked the Battery (New Optma Red with a good charge even for sitting 12.8 Volts)
b. Checked fuse #17 under the hood (Throttle Body Control) 15 Amp fuse good to go... (Received 11.8 Volts on both sides of the fuse)
c. I had the original throttle body which I replaced a couple of years ago with a BBK throttle body so I swapped out the throttle body electronic control module which is connected to the throttle body with no change in the problem.
Don't know what else to do! Need Help! Can you please either post something or give me a call at 803 397-8555!
Thanks!
Roger
Things I have done so far:
a. Checked the Battery (New Optma Red with a good charge even for sitting 12.8 Volts)
b. Checked fuse #17 under the hood (Throttle Body Control) 15 Amp fuse good to go... (Received 11.8 Volts on both sides of the fuse)
c. I had the original throttle body which I replaced a couple of years ago with a BBK throttle body so I swapped out the throttle body electronic control module which is connected to the throttle body with no change in the problem.
Don't know what else to do! Need Help! Can you please either post something or give me a call at 803 397-8555!
Thanks!
Roger
A couple of things to check when you have P1518:
The following may cause an intermittent:
The diagnostic procedure for P1518 has 23 steps of which I posted some of the more obvious things to check. If you need the complete procedure I can provide.
Bill
- DTC P1518 sets if the battery voltage is low. If the customers concern is slow cranking or no crank because battery voltage is low, ignore DTC P1518. Clear any DTCs from memory that may have set from the low battery voltage condition.
- Check the Throt Cont fuse.
- DTC P1518 sets when there is a short to B+ on the TAC module ground circuit. Inspect the fuses for the circuits that are in the TAC module harness (i.e. cruise, brake). An inspection of the fuses may lead you to the circuit that is shorted to the TAC module ground circuit.
- Remove any debris from the PCM\TAC module connector surfaces before servicing the PCM\TAC module. Inspect the PCM\TAC module connector gaskets when diagnosing/replacing the modules. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion into the PCM\TAC modules.
The following may cause an intermittent:
- Poor connections. Check for adequate terminal tension. Refer to Body and Accessories/Wiring Systems for proper procedure.
- Corrosion
- Mis-routed harness
- Rubbed through wire insulation
- Broken wire inside the insulation
- Inspect the TAC module connectors for signs of water intrusion. When this occurs, multiple DTCs should be set and no circuit or component problems can be located.
- For an intermittent condition refer to Symptoms .
- If a repair is completed and the DTC was cleared using a scan tool on the same ignition cycle, the default action will not clear until an ignition cycle has occurred.
- When the TAC module detects a problem within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.
The diagnostic procedure for P1518 has 23 steps of which I posted some of the more obvious things to check. If you need the complete procedure I can provide.
Bill
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Try this
Open the passengers foot well toe board and find the BCM (big silver box). To the LEFT of the BCM,,,you will fine TWO thin grey connectors. Those are the Class 2 Serial Bus connectors. Find the one with FOUR wires. The top of the connector is a shorting bar and connects all the female pins together. Remove the top of the connector. This will isolate those modules from the rest of the serial bus. If there are problems in one of those serial lines, the engine should run normaly.
The circuits on that connector are the LDCM, RDCM and Seat Control Module. Pop the top off that connector and then start the car and see if the problem goes away.
If it does,,let me know and we will find the problem.
Bill
Open the passengers foot well toe board and find the BCM (big silver box). To the LEFT of the BCM,,,you will fine TWO thin grey connectors. Those are the Class 2 Serial Bus connectors. Find the one with FOUR wires. The top of the connector is a shorting bar and connects all the female pins together. Remove the top of the connector. This will isolate those modules from the rest of the serial bus. If there are problems in one of those serial lines, the engine should run normaly.
The circuits on that connector are the LDCM, RDCM and Seat Control Module. Pop the top off that connector and then start the car and see if the problem goes away.
If it does,,let me know and we will find the problem.
Bill
Last edited by Bill Curlee; Aug 18, 2009 at 02:57 PM.