I have a 2008 Malibu, 2.4L, that throws intermittent codes P0650, P1516 and P2101. The car only sets these codes when accelerating from a stop into a left turn and then, only once in a great while. This seems to be more predominant when accelerating aggressively to get into traffic and when it does it triggers the “Reduced Engine Power” mode, making for a very dangerous situation.

P0650 is new but the other two I have been battling for about a year now. I cleaned the throttle body, no help. Replaced the throttle body and performed a tug test on the wires at the TB connector; tug test revealed nothing but TB replacement seemed to solve the problem for about 6 months. I’ve tried running the car and moving/twisting the wires at the connector to get the car to set the codes without any luck. It also shows a P1516 pending and a P2101 pending.

Any thoughts or suggestions would be greatly appreciated.

Did you buy a cheap throttle body?

P0650 - MIL malfunction
P1516 - Throttle actuator performance
P2101 - Throttle actuator performance

If this kind of behavior happened before and after the throttle body replacement, I suspect the wiring. That the behavior paused after you replaced the throttle body, then started again a few months later, tells me that wiring and/or the plug has an issue. You move it around etc. unplug/replug, wiggle/kick/bounce, pat it nicely, now it is good. Some heat/cold/moisture/dry/vibrations/g-forces/etc. then finally it gets to the right position to become sad once again.

If it were me, I'd look at all contacts in the plugs and see if there isn't some dust or corrosion or something, then unplug, move it around etc. unplug/replug, wiggle/kick/bounce, pat nicely, etc. and see if your problem is temporarily resolved again. If so, you'll be able to home in on the issue.

It wasn't cheap to me, $215 with the governor'* share.

Sorry for the late response. We have a storm coming through and I have been trying to prepare for that.

A wiring issue is where I'm leaning as well. It just seems strange that it only happens when making a left turn from a stop. I've tried to identify anything that might shift in a left turn but haven't had any success, It will go for months then all at once it trips the "Reduced Engine Power" and sets one or more codes. It use to set the TSC code with the 1516 code but since I replaced the throttle body I haven't gotten the TSC code, which makes no sense to me. Typically, if I rest the codes the car will go for quite some time before its sets them again. It seems to me that the driver information system in this car is not well engineered. Posting on a forum is kind of a last resort for me, after I have exhausted all my ideas. I figure all of us are smarter than any one of us.

I think I am going to strip the wires back and replace the plug. It may be months before I know whether or not that has fixed it, if I know then!?!

Keep in mind that once a code sets, it will act based on that until it sees it resolved for a while. This could help explain how it acts badly for a while after setting a code.

Bad grounds can be related to this kind of thing as well. It might not be that particular harness. It might be some ground point on the other side of the car.

I would clear it and start tugging on some wiring and see if you can get it to set.

Good point. I’ll try to chase down the grounds. Thanks for the suggestions.

I’ve tried this already but didn’t get any change when I tugged, wiggled, pulled, looked at them crossly, or anything else. It’* been almost a week is since I cleared the codes and they haven’t reset. I really suspect a connection at the plug on the TPS.

Wait a second. This is new and valuable information pertinent to the diagnosis of this vehicle. Exactly how crossly did you look at them? Are we talking mildly perturbed, dour, annoyed, vexed, galled, or stern?

LOL sorry, couldn't resist!