I have a 2000 V-6 camaro that runs like a dream then when you shut it down for a few hours it will not start. It trips code P1518 wich I think is something about low voltage to the Throttle or something like that. The battery is brand new and it is over 13V. If you clear the code with a scanner, it will start right up and run fine till you leave it sit for an extended period then it won't start and you have to reset to code again. When you get it started it runs great. I replaced the gas cap as I read on the net that it could be the trouble but it isn't.

Anyone able to help??

 

P1518
This trouble concerns the "fly by wire" throttle". The engine fails to start because the the PCM keeps the throttle fully closed if it does not get good data.

CIRCUIT DESCRIPTION
The throttle actuator control (TAC) module and the powertrain control module (PCM) communicate via a dedicated serial data circuit. This serial data circuit is separate from any other serial data circuit on the vehicle. Accurate transmitting and receiving of serial data requires not only good circuit integrity but also adequate system voltage. This diagnostic monitors the accuracy of the serial data transmitted between the TAC module and the PCM. if the PCM of the TAC module detects a loss of data or invalid data, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
The ignition switch is in the crank or run position.

CONDITIONS FOR SETTING THE DTC
Invalid or missing serial data messages are detected for a predetermined period of time.

ACTION TAKEN WHEN THE DTC SETS


The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
CONDITIONS FOR CLEARING THE MIL/DTC


The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
DIAGNOSTIC AIDS
Inspect for the following:

IMPORTANT: DTC P1518 sets if the battery voltage is low or the PCM is replaced or reflashed. If the customer's concern is slow cranking, or if the engine is not cranking because the battery voltage is low, ignore DTC P1518. Clear any DTCs from memory that may have set from the low battery voltage condition.

 

Thanks for the reply but what is the fix? I know that it isn't low voltage from the battery. One because it is new and two because if I clear the code it will start without doing anything with the battery. Can the throttle control be partially bad and reseting the code fixes it till it is shut off again? It runs great when it starts and if it doesn't start I just have to clear the code it will start right up. When I drive the car and stop for short times it doesn't happen. It just seems to happen when the car has been turned off for several hours. It also shows a pending code of P466 (I think that is the one) my scanner says it is for the Evap System. Seems like it is something simple sinse it runs OK when it starts. I would think if the TAC were bad that it would be bad and not start at all.

Anyone know where to start?

 

Well I got it fixed. There is a sensor in the top of the throttle body with 2 screws in it and a plug. I took it out and it looks like it has 2 resistors inside of a tube. One of the resistors had a little string of what looked like carbon on it. I brushed it off, cleaned with some carb cleaner and put it all back together. Car hasn't poped the code for 3 days now. It use to do it after sitting for just a couple of hours.

 

that sensor was the maf, for future reference

 

New here... My Son is having the same codes and problems. His car has been in and out of the dealer. They can't find what's wrong.

Please let my know what it was to fix your car. The dealer keeps guessing.

 

I had an intermittent 1518 code, crank but no start on my 2000 camaro. It would let me clear the code and then it would start. Then it started no allowing me to clear the code right away. I'd try to clear it, crank it, try to clear it. After awhile it would clear and start. Finally one day the engine just stopped while pulling out of my drive. Wouldn't clear 1518 and wouldnt start. I checked Tac connections, engine grounds, went through dozens of forums nothing helped, until I checked my ignition relay. If it's bad, the ingine will crank but it won't send voltage to your throttle body.