Well I scoped out all the wires on the ABS and everything measured normal. All the sensors are there, the GMLAN is doing its thing normal like and all power and grounds are perfect. Theres alot of stuff in these modules but not really alot of wires. The pins stick out on the board so its easy to go thru them all with minimal hassle with it running in the car. Ill silicone the cover back on eventually. Got a baggie over it for now. So that C0561-71 invalid serial data received, is a rather worthless description of whats really going on. Thats a bummer so I will have to check on many ideas I been finding in the Youtubes. Its even possible that the steering malfunction could be causing it. But Im not so sure.The steering resets when restarted. And my reader resets the trouble code. Yet the Traction control light will activate before the steering craps out again. So now Ill look at the VVT train. I already looked at the actual valves and the are both clean and functioning. Ill have to be looking at maybe the chain streached too far or those plastic guides maybe worn too far and getting into timing grey zone. Thats more complicated but this reader will chart the intake and exhaust timing, so maybe I can see if there is a problem there. I have seen a P0014 pop up once that I noted. But I figured it was due to pulling plugs off. It has not poped up again so its hard to say. A youtube video said that ABS really watches anything that can have an impact on torque to determine weather to shut off the ABS system. And VVT is big on torque impact. Any ways, its got to be done before a dealer gets his hands on this or I will be subjected to the hard sell to dump this car for another one with problems of its own.

 

I don't know where you got the definition, but the actual definition is "System disabled information stored".
In short it is not the EBCM or anything attached to it. It is something preventing the engine to go into torque limiting mode.
Here is a pdf on the subject from the Shop Manual

C0561.pdf

 

Yea Ive seen that PDF but its looks incomplete like its an early document or a watered down document for some other purpose. Many other websites post the added wording as does the Tech2. Im not saying the wording is accurate, but its republished all over the place. Its possible that the error flags on actual communications errors, but there are no signs my car has these comm errors. And I currently have no errors on the ECM or BCM. So I am figuring the ABS is monitoring actual performance data from the ECM and it doesnt like what it sees. The scope shows there is non stop communications going on with the ABS. So its getting constant info of some sort. With no other errors currently to check and a smooth running engine, I am left with investigating the valve timing to see if there is something to see. It could be having troubles that are not yet noticable. So the Youtube videos say. Oh and I do notice a reduction in horsepower in the higher gears. Not sure if its transmission related though. I know trany is being held back, but VVT could be held back as well. And all this started when the steering started quiting on me. There is one Youtube I saw that said a missed oil change can trigger a C0561-71. Hah. Well thats not my case but if it can happen, then its just further proof that many things may have to be checked to nail this error down. Tech2 says brake fluid and engine coolant are fine. Im not yet checking spark plugs but I will get to them if I start to run out of things to check. Hah.

 

I got mine from the Shop Manual.
Reminds me of the Chevy service writer that told me it's not his job to read technical service bulletins.

 

Unfortunately life doesnt wait for me to fix my car so I got sidetracked all over the place. But been banging on it from time to time. I put a oil pressure gage on it and it read over 100psi and blew the sensor open. That was cause for concern. So eventually I pulled the timing chain cover off and checked it all out. I couldnt see any problem. Chain is perfect condition with no sign of stretch, the plastic guides show no sign of gouging, and tensioners are sitting where they have plenty of room to move and keep up with wear. I looked at oil pump and relief valve and they both look and move smoothly. Just in case, I swapped the whole front cover with the engine I will put in Dads car. Then I bought a new oil pressure sensor for the gage and fired it up. Same thing. Cold, the pressure pegs the meter at 100psi. As it warms up it idles 25psi at 600rpm. And 75psi at 2800rpm running speed. Thats just the way it is. Before I figured it all out. I called the dealer and they said my engine had a serious malfunction and needed their immediate help before it had a fatal failure. I really dont like talking with dealers. I looked up the oil sensor specs and they are supposed to hold up to 400psi so I just had a bum sensor. That relief spring is the sole reason this engine has high oil pressure and 2 units give the same pressure. So its normal and not hurting a thing. So its not the cause of the C0561-71 code trip. I figured out more of the function of this VCX tech2 and its very impressive but not user friendly. You have to figure out what setting to use on your car. It doesnt figure it out from the VIN. I was entering 2006 when I was getting more tools by entering 2007. Now I can plug in, go into trigger mode and watch lots of the sensor activity till the trouble code Im interested pops up. Then this reader will record before and after data to graph when the code trips. But a funny thing was happening. When the reader is plugged in, I no longer got traction control code trips. Unplug it, and its trip city and loss of half of my engine power. So its now clear the small load from this tiny reader was smoothing out communication. And those codes, c0561-71 and the Exhaust cam advance code were both red hearings. But I still get power steering code trip. I got to go to florida now and dont like the idea of no power steering. So I swapped out the motor with the one in Dads car. It was a very easy swap of 2 easy bolts and one plug. No more power steering shut offs. So for sure, the motor is bad. And I will head to florida with that reader plugged into the port. I already cleaned the ECM cable plugs that looked clean anyway. So I suspect the wet carpet is making corrosion issues nearer the BCM causing random errors. When we start getting more of this global warming I been hearing about, then maybe I will take a harder look at how to dry out the carpet and fix the leaks. The reader plugged in draws less than 100mA so I can leave it in and on with no chance of draining the battery dead. If something comes up, I can plug my PC in and see and reset things for the time being.

 

Probably a corroded ground wire under the wet carpet. Safe journey to Florida!

 

Thanks. Im sure you are right about the grounds. I may jumper the port ground to the frame and see it that ends the problem without the reader plugged in.

 

I moved your posts, and all related responses, to this new thread. The other thread, "quick power steering fix", did not apply to what you're experiencing.

 

Got an update. Did the site change too? I thought it was a very pale blue last time I remember. I had to look up search to see if I was on the wrong forum. Anyways, I had issues with the trouble codes for Exhaust variable valve sensor and a strange communications error with the antilock brakes that also pointed to the BCM module. It was all very convoluted. I switched out brake module and exhaust VVT valve to no joy. I messed around with grounds but didn't find anything super ugly. I would have ignored it but the errors kicked the trany in an undesirable limp mode that made it shift really clunky. I changed out trany module and didn't get a fix. As winter wained, the errors would stay cleared longer making it tougher to trouble shoot. Finally headed to Florida with trouble codes. I cleared them as I was driving. But the thing is, no trouble coded popped up the whole way down. But I was down on gas mileage. 24 instead of 30. Bummer. Stopped in Georgia with friends and looked up the O2 sensors. I didn't get a trouble code on them, but the diagnostics said the trailing O2 sensor had a bad heater. I was perplexed because the actual data looked very normal. The engine side sensor data jacked around as I punched the gas. While the trailing sensor stayed very steady all the time. Anyways, sensors are cheap and I had tools. So ordered a new one from Amazon for next day delivery. Installed it and shazam. Diagnostics said the heater was bad. Hah. Figures. So my cool Chinese Tech knockoff tool was not 100% flawless. But it showed the new sensor gave pretty much identical data. Just what a good sensor would generate. So I packed up and continued to Florida. Gas mileage was up to 28. Looked it up and realized it never was up to 30. Oh well, at least I'm getting the max. And no more trouble codes for the rest of the trip. Flawless drive performance... Till I got back home. I filled up my empty tank and unloaded my trip luggage. The next day I had all the same trouble codes. Isn't that some kinda crap. A real head shaker. Anyway, I realized that the codes popped off when my cold engine was first headed down the road. Not when started, but almost the same spot in the road a quarter mile away. So I started thinkin the air temperature stuff may be the culprit. I started cold and didn't warm up the engine. When I warmed it up, no trouble code. Unless it was especially cold. We had mild cold mornings and bitter cold mornings when I got back and paid close attention to both. So I went and changed out the MAS sensor. Cold air changes that. I figured I hit the jack pot. No errors after initial change because the engine was warm. But the next day, I had errors again. Unbelievable. Mind blowing. What the hell could it be. It works great in warm weather but takes a dump in the cold. And all the temperature sensors show good in diagnostics.

So life goes on and keep my laptop in the passenger seat to keep clearing the codes. What a hassle, but it has to be at the ready in case a new code pops up that actually IS the problem. Eventually I had to take a trip for my work that gave me highway miles. And I was surprised to find that my gas mileage was down again. What the hell. Its got a new sensor. I still got the old sensor if I need it. I looked up the O2 data and it still says trailing O2 heater bad but the data is just like its supposed to be. Its still cold but not bitter, so one code clearing, and it stays that way while the engine is warm.

Then I suddenly had a big thought....................WHAT IF ITS THE GAS!!!!! It may be a crazy thought, but it makes perfect sense if you hear the details. I burn all my gas getting to Georgia. And I got low gas mileage. I buy Georgia gas and Florida gas down and back and get no problems at all. I am empty by the time I get home and fill up with my gas. And I got all the same problems all over again. Soon, the weather finally gets mild and I only get the VVT valve error which doesn't trip the trany. I suddenly get the gas idea and fill my tank at the gas station. I clear out the VVT code and I don't get any more codes for the rest of the tank. And that folks is how I figured it out. You see, I have not been filling up at the gas station. I bought 400 gallons of gas when the pandemic dropped gas prices to $1 per gallon. I kept it in 60 gallon barrels inside my shed. I have an air powered pump that Id stick in each barrel and fill my car with. So while gas has been going crazy, I been driving for nearly free. But the gas is over 2 years old now. And its now clear that HHRs don't have a clue what error code to trip when low octane gas is used. Since its warm now, only the VVT code is tripping. So old gas works good enough in the summer. And since gas went off the cliff, I been burning the rest of my old gas. I'm on my last tankful now. And I wish I had bought more. But at least I finally figured out why all this trouble. If I had gone to a shop, there's no doubt I would have been taken to the cleaners and regretted ever being a gas hog. But now I know to expect trouble codes if I ever get old gas again. I got VVT trouble code now, but it will be done as soon as I start buying that crazy $4.75 gas.

Anyways, I still have a steering motor that trips off that may be under warranty. When I get time, Ill call around and try to get positive info from dealers about a free replacement. If I can get a comittment, Ill put the bad one back on and get it fixed. I will eventually need a good power steering motor. Its lookin like I will soon have an error free car.

 

Low quality gasoline might contain the minimum amount of detergent additives. That and a lot of short trips would likely cause some carbon buildup that would cause knocking. A long trip might burn off that carbon.