If your valve body is stuck open or closed, would that cause your car to not turn over???

Jeff, your answers should be down here. Doesn't the Throttle Body have a 'Learn Procedure', if replaced?

P2104 - Throttle Actuator Control (TAC) System - Forced Idle Description: The TAC system is in the failure mode effects management (FMEM) mode of forced idle. Possible Causes:

• Open or short in multiple accelerator pedal position (APP) sensor circuits.
• Damaged APP sensor.
• Damaged powertrain control module (PCM).

Diagnostic Aids: This DTC is an informational DTC and can be set in combination with a number of other DTCs which are causing the FMEM. Diagnose other DTCs first. Application Key On Engine Off Key On Engine Running Continuous Memory All

P2112 - Throttle Actuator Control (TAC) System - Stuck Closed. Description: This powertrain control module (PCM) fault status indicates the throttle plate is at a lower angle than commanded. Possible Causes:

• Binding throttle body, stuck closed.
• Damaged PCM.

Diagnostic Aids: Application Key On Engine Off Key On Engine Running Continuous Memory All GO to DV1 Are you familiar with electronic throttle control ? You have a dc electric motor on the throttle body an at the gas pedal there are APP pedal position sensors that send voltage signals to the PCM which in turn controls the electric motor opening an closing the throttle ! By what this P02112 states the throttle plate is binding , which means it could be bad or just needs to be cleaned ! You will need to disconnect the electrical connector an see if it is binding by pushing it with finger or thumb . which is ever easiest !
GO to QE1

Need to be more (way more) specific. An intake man. is a one piece, aluminum device, with "runners" going into the head where your intake valves are operating open and closed to allow the engine to run. Nothing on the intake opens or closes, or moves in any way. The big butterfly valve at the opening of the intake(part of your throttle body, where the air comes in), Is this what is stuck open? It's controlled by your accelerator linkage, and a spring to bring it closed. Spray with carb. cleaner, reach in as far as possible with a rag to clean it as much as you can, and work it back and forth to free it up, if it's stuck.

DTC P1512 - VARIABLE TUMBLE CONTROL SYSTEM (VTCS), STUCK CLOSED
The air intake hose that goes from the air filter/mass airflow sensor to the throttle body they are common to crack. This air leak can cause a lean condition if that checks out ok then the issue is usually a faulty mass air flow sensor .This would need to be checked next.

Usually the actuator valve is stuck closed. These are the most common causes of the P1512 and possible causes are:
* ECT sensor malfunction.
* MAF sensor malfunction.
* IAT sensor malfunction.
* EGR boost sensor malfunction
* TP sensor malfunction.
* CKP sensor malfunction
* VTCS solenoid valve malfunction.
* VTCS shutter valve stuck closed.
* VTCS shutter valve actuator stuck closed.
* Short circuit between PCM and VCTS solenoid valve.
* PCM malfunction.

I would start with the mass air flow sensor this can cause all these issues. Then the cat. This would be the next step.

I hope this helped (remember to rate and comment this answer).

When you turn the key to start what happens ? Does the starter engage an spin the engine ? This would be a crank - no - start condition . Or when you turn the key nothing happens ! This is a no - crank - no start condition . If the engine does spin when turning the key to start and it doesn't start an run you need to see whats missing - spark , fuel or compression . Videos on youtube showing how to test . You need to hook up a fuel pressure gauge to check for fuel . Just pushing the valve on the fuel rail isn't good enough .
No Start Diagnostic Basics EricTheCarGuy

unfortunately no ! Your best bet take it to the dealer . The P0420 always ends up being the catalytic converter ! P2104 isn't throttle air control . P2112 - Throttle Actuator Control (TAC) System - Stuck Closed. Description: This powertrain control module (PCM) fault status indicates the throttle plate is at a lower angle than commanded. Possible Causes:

• Binding throttle body, stuck closed.
• Damaged PCM.

Diagnostic Aids: Application Key On Engine Off Key On Engine Running Continuous Memory All GO to DV1
P2104 - Throttle Actuator Control (TAC) System - Forced Idle Description: The TAC system is in the failure mode effects management (FMEM) mode of forced idle. Possible Causes:

• Open or short in multiple accelerator pedal position (APP) sensor circuits.
• Damaged APP sensor.
• Damaged powertrain control module (PCM).

Diagnostic Aids: This DTC is an informational DTC and can be set in combination with a number of other DTCs which are causing the FMEM. Diagnose other DTCs first. Application Key On Engine Off Key On Engine Running Continuous Memory All GO to QE1
P0506 - Idle Air Control (IAC) System RPM Lower Than Expected For Vehicles With Electronic Throttle Control (ETC) Description: This DTC is set when the powertrain control module (PCM) detects an engine idle speed that is less than the desired RPM. Possible Causes:

• Air intake restriction.
• Exhaust restriction.
• Engine mechanical fault.
• Damaged electronic throttle body (ETB).
• Damaged PCM.

Diagnostic Aids: This DTC is informational only and it may be accompanied by other DTCs. Diagnose other DTCs first. If other DTCs are not present inspect the intake air system for air restrictions and damage. If no concerns are present, clear the DTC and retest. For All Others Description: This DTC is set when the powertrain control module (PCM) detects an engine idle speed that is less than the desired RPM. Possible Causes:

• IAC circuit open.
• Air inlet is plugged.
• B+ or VPWR to IAC solenoid open.
• Damaged or incorrect IAC valve.
• IAC valve stuck closed.
• VPWR to IAC solenoid open.
• IAC circuit shorted to PWR.

Diagnostic Aids: Disconnect the IAC valve and look for little or no change in engine RPM as an indication of a stuck or damaged valve. Application Key On Engine Off Key On Engine Running Continuous Memory Vehicles With Electronic Throttle Control (ETC) Refer to the Description, Possible Causes and Diagnostic Aids for the DTC. All others GO to KE1

That code is the EGR. I'd start by checking for a bad connection on the EGR plug-in. Pull the connector off and inspect each individual terminal inside the plug and the connector pins inside the EGR valve.
I found this solution at another forum on this issue. It worked on my 2001 Grand Am:

"Many GM built cars have a tendency to have the 'Check Engine Soon' light come on as a result of DTC code P1404. P1404 is described as EGR valve pintle stuck open, which in most cases is a false alarm. I had this happen with my '01 Grand Am. A little bit surfing on internet reveals that GM has a solution for the problem, a re-flash for the car's computer.

A software re-flash as a fix kind of indicates that the vehicles with this problem were built with it but I don't think GM will be re-flashing cars outside warranty for free. They will want their $100 for it.

Some hands on people I found had purchased a new EGR valve and changed it but the problem remained.

Possible reason (very likely) for the false P1404 code is that the plastic piston of the EGR valve position instrument (LVDT?) wears over time and starts reading a different position at valve closed than what it was when the EGR valve was first installed.

When the car was built and the computer circuits energized for the first time the computer learned the EGR valve closed position signal from the valve position instrument that is built on top of the valve itself. Over time, when the instrument wears, a slightly different signal is sent to the computer and when it differs enough from the 'Valve Closed Signal', that the computer had learned, the trouble code P1404 is set and the 'Service Engine Soon' light comes on.

Replacing the EGR valve with a new one does not necessarily fix this problem because the 'Valve Closed Signal' between valves is slightly different and it is just pure luck if your new valve would give a 'Valve Closed Signal' close enough to your original valve's signal not to set the trouble code. This is why the new EGR valve 'Valve Closed Signal' must be re-learned by the computer.

So, what this all means is that if the P1404 is a false code meaning that the valve pintle is not stuck open, then new 'Valve Closed Signal' can be re-learned by the computer using the old valve.

For fixing this problem the tool you need to have is a simple OBD II code scanner that can be used to erase trouble codes. There are many scanners of different price range on the market. I purchased one from AutoZone for about $90.

A code scanner is a very handy tool to have and I recommend everybody who is just slightly hands on type of a person to get one. It will end up saving a lot of money over time.

The fix goes like this:

1. Disconnect the wire harness from the EGR valve.

2. Turn key ON and erase the trouble code(s) from the car's computer AND TURN KEY OFF IMMEDIATELY WHEN THE SCANNER SAYS CODES HAVE BEEN ERASED. DO NOT TURN KEY ON BEFORE YOU RE-CONNECT EGR WIRE HARNESS.

3. Re-connect EGR wire harness and your problem should be fixed.

I learned this fix from OBDII.COM where carfixer and kozloski discussed it and I think kozloski was the one who provided the solution, so thanks to them.

There was also other people stating that this fix really works. Now I have joined this group of people as I got mine fixed using this trick also.

I believe erasing codes with wire harness disconnected and turning the key OFF right after P1404 code has been erased re-sets the 'Valve Close Position' reading in the computer and triggers computer to re-learn position next time the key is turned ON.

If you don't have an OBD II scanner and don't want to buy one some car part stores may erase the code for free, but if you have it done there you must tell them about turning the key OFF at the right moment. Other wise the re-learn process does not take place.

It could cause it not to start if it's stuck open.

If the EGR valve is stuck open, it will essentially cause a vacuum leak, leading to inefficient combustion, rough idling, hesitation, and sometimes stalling in extreme cases. This is because the car cannot combust on carbon dioxide from the tailpipe — it needs atmospheric oxygen. If the combustion chamber is flooded with exhaust from an open EGR valve, it will not function properly. To check and see if the EGR valve is stuck open, have someone idle a parked vehicle with the brake on while you examine the plunger shaft to see if it is stuck open
.
If the EGR valve is stuck closed, emissions of nitrogen oxides will rise, and the car may start to knock. Spark knock happens when the fuel mixture in the combustion chamber ignites before it has been reached by the explosion in the cylinder, resulting in a disruption of the engine timing. In this instance, the engine should be warmed up and revved to see if the EGR valve will move.

Does it stick closed? If so you have turn the adjusting screw just enough to make it not stick. The manufactures usually make this a tamper proof task so you may have to get creative. If you can find the adjusting screw they have made so you can't just turn it with a screwdriver you have to use a vise-grip or something like that to turn it. It usually only takes about a 1/4 turn.

You probably caused a short circuit when you changed the light. Change fuse #14. Next time, don't turn the lights on until you are finished changing the lights.