07 Vue Hyrbid horrible screech & auto stop/start fail
 

I have a 2007 Saturn Vue Hybrid 2.4L engine. For a bit now the Auto Start has been failing, and not only that but an awful screech happens when the Auto Start kicks in (loud and bad enough to turn heads). I've been completely avoiding coming to a complete stop because of the noise and the fact that most of the time the Auto Start will try to kick in and the car won't start so I will have to shift to Neutral and turn my key again to start my car. It's picky when it decides to do this but if I'm parked somewhere for a while the engine will quiet down(sometimes turns off sometimes it doesn't completely) and the Auto Start will kick on (sometimes it does this a couple times within a short time frame), a few times it's able to start the car again and other times I just to turn the key.

I've already replaced the Starter, and the Belt last summer. I just replaced the Engine Coolant Temp Sensor a couple weeks ago. I connected my OBD Reader and it's telling me "Auxiliary Transmission Fluid Pump Performance" and another code with "Likely Fix; Replace Auxiliary Water Pump"

Has anyone had a Auto Stop/Start issue before? Is there a way i can test my Auxiliary Water Pump to see if it's working without one of those fancy scanners with commands (checked all data and their test steps involve a fancy scanner)? How can I test the belt tensioner, is that something that can be tightened?

I'm a small lady and this car needs a lot of work so I'm working with "slowly but surely" and I don't have the funds to take it to a mechanic and rack up a huge bill. My boyfriends currently several states away and my dad is out of the question. I'm making do with what I can do myself for the most part as in finding the issue (hopefully) and getting the parts myself somewhere cheaper and if need be finding someone to put them in.

Any advice helps!:confused:

What does OBD-II fault code P2797 mean?

OBD-II Code P2797 is defined as a AUXILIARY Transmission Fluid Pump Performance

The Drive Motor Generator Power Inverter Control Module contains the Motor Driver that controls the Auxiliary Transmission Fluid Pump, The Auxiliary Transmission Fluid Pump creates hydraulic pressure in the transmission, allowing the transmission to be able to shift gears. If the Motor Driver detects the pump is not capable of producing the pressure requested, code P2797 will set.Additional codes are usually stored along with code P2797 and should be diagnosed and repaired first.

Sounds like that pump needs confirming diagnosis and likely placement. Not sure if the screeching sound is coming from inside the transmission or by the serpentine belt. Have a friend who start the car while you are around the front of the vehicle and trace down the general location of the noise. If there is also a code for the auxiliary water pump, it may mean that part of the system also needs to be diagnosed. The transmission may be overheating, causing the auxiliary fluid pump not to work properly
I do not know if these parts are internal or external to the transmission but I would think they are internal.

Columbus the last time you drained and refilled your transmission fluid? I would start there. If you have someone else do it, tell them that you want a full fluid replacement, NOT a glush

For as long as the car has been with me, no one has ever mentioned checking the transmission fluid. I'm assuming if the engine was overheating a warning light would pop up since there isn't a temp gauge? The Auxiliary Water Pump is external and sit a little lower than where my Engine Temp Sensor is.

The noise doesn't happen when the car is started manually, it happens when I'm driving and I come to a stop and the Auto Stop kicks in when the rpms drop and as soon as I let my foot of the brake is usually when the screech happens as the car is trying to Auto Start. I assume it's from the belt or whatever part of the car controls the Auto Stop/Start function it has

The alternator starts the car in hybrid mode. The auxiliary pumps are necessary to make the car function in hybrid mode. There is an extra belt tensioner to allow torque from the alternator to spin the engine on hybrid restarts. You will need to find a shop that has experience with this type of GM hybrid system.