Having an issue with my 2009 Pontiac G5, giving error codes for throttle/pedal position

Question edited for clarity and typos. Not sure what you mean by "ECM 2009 from a 2008" though.

There will always be a learning period when you put in a new ECM. First clean the Throttle Body and MAF.

Then you may need to relearn the Throttle Position Sensor.

You can Google all this stuff.

https://www.google.com/search?q=2008+pontiac+g6+throttle+position+sensor+reset

..

If drive by wire throttle, integrated into throttle body. You would have to replace throttle body. Was there a trouble code? If so, can you post the code? You need to have this properly diagnosed. I don't doubt your ability, but, tps not serviceable.

P2123 OBD II Trouble Code Throttle Pedal Position Sensor Switch Circuit...

When you replace throttle body did you replace the sensors or reuse the one you had. If it's drive by wire it could be the ACCELERATOR PEDAL ASSEMBLY PEDAL POSITION SENSOR or the signal from pcm

P0120 Throttle/Pedal Position Sensor/Switch A -Circuit Malfunction
P0121 Throttle/Pedal Position Sensor/Switch A -Circuit Range/Performance Problem
P0122 Throttle/Pedal Position Sensor/Switch A -Circuit Low Input

,try changing the throttle pedal switch/mechanism on the floor in the cabin

P0010 Intake Camshaft Position 'A' Actuator Circuit Open Bank 1
http://engine-codes.com/p0010.html

You must get the error code read for the check engine light in order to get helped here. Bring your vehicle to a local autozone to have your vehicles computer scanned, its free or local shop (most charge for this). Post the codes on fixya for further assistance.

Code 1577 - Pedal position sensor disagreement between sensors

Having read most of the other posts regarding EFM issues it would appear that there are a few main suspects: Brake Switch : Dirty Throttle Body : Throttle Body Connections : Accelerator Pedal Sensor.

Given that the car operates without issue on cruise control and using steering wheel speed adjustment, I am guessing the problem is with the Pedal Sensor.

After tightening the Throttle Position Sensor I had about 4weeks of no warnings. Then on a very rainy day I drove from Dundee to Edinburgh and at the end of the trip the EFM warning re-surfaced. I took the car to get the OBDII codes read and the technician flagged up 1 code: P1577 Pedal Position Sensor Disagreement btwn Sensors.

He cleared the codes and suggested that I might think about cleaning the connections. However since he cleared the codes I have had no more warnings and am reluctant to do anything at present.

I think that all the snow (much of which I dragged into the footwell with my big workies boots) has created a little to much damp in that area and some of the water has evaporated then condensed on the PPS.

Hope helps.

There is a TSB on this issues if your having ignition lock issues.
Service Information
2009 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | View All Bulletins | Document ID: 2325129
#09-02-35-005: Ignition Key Difficult to Remove, Ignition Key Binds or Sticks in Cylinder (Replace Ignition Cylinder) - (Aug 10, 2009)

Subject: Ignition Key Difficult to Remove, Ignition Key Binds or Sticks in Cylinder (Replace Ignition Cylinder)

Models: 2008-2009 Cadillac CTS (Built Prior to VIN Breakpoint 90163371)

2005-2009 Chevrolet Cobalt (Built Prior to April 14, 2009)

2006-2009 Chevrolet HHR (Built Prior to April 14, 2009)

2007-2009 Chevrolet Equinox (Built Prior to July 2008)

2005-2006 Pontiac Pursuit (Canada Only)

2006-2009 Pontiac Solstice (Built Prior to April 14, 2009)

2007-2009 Pontiac G5 (Built Prior to April 14, 2009), Torrent (Built Prior to July 2008)

Attention: This bulletin only applies to vehicle equipped with automatic transmission.

You need a new ignition switch, mine had the same problem, its a defect some of the G5's have.