jermdm

Just like the title says, Is there any GM techs on here? I have a few questions about my 06 Grand Prix GXP that has some issues. Can send PM's. I work at Ford with access to anything about Ford vehicles but don't have much access to GM stuff. Don't have any problems with my IROC though.

TURBOJOE

Im not a GM

TURBOJOE

Sorry its early ! I'm not a GM tech but I have been an ASE master tech for 25 yrs. I work in a private shop doing diagnostics and I own a 2006 GXP. What kind of problem are you having ?

jermdm

Its cool that a fellow thirdgener has a GXP car. Is yours a Grand Prix also? The problem I'm having is with the DOD and the ABS. The DOD works but doesn't operate properly. When it turns on, I can watch my short and long term fuels start adding fuel like crazy. Highest I seen is +22 on long and +18 on short. Sometimes the system will shut down and show FLT on my scanner. When this happens, I usually get a P1101 intake air flow performance code. Other times, the DOD doesn't shut down but I still get long and short terms adding fuel. I've been trying find what the enabling conditions are for DOD operation(vehicle speed, engine temp, gear range, etc). I can find inhibit conditions but not enabling. The DOD will turn on at 20 to 25 MPH at light throttle even when the engine is cold in stop and go traffic. I thought it was mainly for highway driving. The ABS is strange. The ABS proves out when starting the vehicle. As soon as I start moving and get to 3 MPH, the ABS pump motor cycles. I will do this with every ignition cycle. I think the motor should cycle when the system proves out when starting the car, not when you reach 3 MPH. These are just the basics of whats going on. I have so much more info but don't want to overwhelm you. I'm also having a couple of small tranny problems and I'm thinking it could be related to these issues. Just like your take on whats going on.

TURBOJOE

Mine is a GP also.The ABS operation is normal for these cars. I wonder if your DOD has a problem where it is disabling the injectors to the cylinders but isn't disabling the lifters and pumping oxygen into the exhaust causing a false lean condition.On trans problems , I had an intermittent RPM flair and thump into gear and when accelerating from a stop caused by a bad pressure control solenoid in the trans and have replaced quite a few others on customers cars. Hope this helps.

TURBOJOE

The DOD problem could be causing the MAF code because the engine is flowing more air than it should when in DOD .I disabled my DOD - annoying exhaust note . esp. in town and it was causing an oil consumption problem , it did engage at the speeds you listed

jermdm

Thanks for the info. I was also thinking that the lifters or some of them were still opening and closing when DOD is engaged and injectors turned off. That explains my lean as I do get a P0171 from time to time. I have turned on the solenoids for the DOD 1 at a time manually by grounding the wire at the PCM and each cylinder made an equal change in the motor. Only did this for a couple seconds as I know the injectors were still pulsing fuel. Good to know about the ABS. Fords operate different and that's what I'm use to. My trans does the same thing. From a stop, I take off and the trans slips and bangs in to gear. Doesn't do this all the time. I've read that the pressure control solenoids are a problem with these cars. Atleast I know someone else is having the same problems and has fixed the issue. The car just seems like it doesn't want to move when taking of from a stop when it doesn't slip. Just seems so sluggish. The car will get up and go when giving a lot of throttle after the car is moving. No problems with power. Is it a pain to change the pressure control solenoid? From what I've read, it is. Thanks again.

TURBOJOE

Pressure sol. is in trans side cover on drivers side , need to drop lower susp member that control arms attach to down on drivers side enough to get cover off , kind of a pain , even on a lift . Don't wait too long as sol. is causing intermittent low line pressure in trans that can burn it up. Mine felt sluggish from a stop also , the sol fixed it all.

jermdm

How did you disable the DOD? I've thought about doing this also since I really don't care if the DOD is operational. Did you use a tuner or is there some other way of doing this without having the SES light staying on. Thought about depinning the solenoid wires at the PCM but the PCM will still try to activate the DOD an disable the injectors causing running problems.

TURBOJOE

Diablosport I-1000 tuner , can do some fuel tweeks ,, trans firmness adjusts ,ect also

jermdm

Great. Thanks for all your help. If you need help with something, let me know.

Lurbie

iTrader: (3)

Looks like you've got it figured out, but just to confirm in case someone else questions it, the ABS self test is normal, the vehicle wants to see speed during the test. Not very familiar with the DOD operation as I do more Chassis/Electrical work, but I've heard those can enable at pretty low speeds like you're experiencing. I've also had similar PCS (press. control solenoid) problems on other GM vehicles I owned. In my situation it would hit so hard on upshifts you'd think you were just rearended by a fully loaded semi. I hate doing auto trans work, so I paid a trans tech to do it for me. The side gasket may be re-useable (it was in my 01 Montana), so if it is not damaged and not currently leaking, you might be able re-use it and save that money.

jermdm

Thanks for your input. This is the first time I've owned a car like this and this new. I've always owned older cars with less electronics and modules. I only have experience with Fords and I know there systems and strategies very well, so that's all I have to go on when diagnosing other brands. I just bought the car from another dealership a few months ago which it came with a warranty and I'm going to see if the pressure control solenoid would be covered and run the work thru the dealership I work at. The trans side cover doesn't leak nor is there any leaks on the engine. The trans lower pan has slight seepage which isn't a big deal right now. The car has 120,000 on it so I knew it would need some work when I bought it. Also going to see about disabling the DOD. Should be a speed shop here in Cincy that can do it. Don't have the money to buy a tuner/programmer to do it.