Shifting hard and codes P0700, P0716, and P0717

If in fact you have the same codes, we do need to look for a common denominator. The TCM would be a common component so we need to jump to that and test it to make sure that is the issue. Take a look at the attachments and I highlighted the test for the TCM.

Let me know your results and we can go from there. Thanks

I have already replaced the transmission input speed sensor though, along with the throttle body and sensor, as well as the accelerator pedal with sensor, and wired in new connectors for the transmission input speed sensor and the throttle body sensor in case the wiring might be bad. The only thing out of those I have not replaced yet is the TCM.

There is always a chance that we got a bad part but I am with you and I would go ahead and replace the TCM. Just be aware you will need to program the new TCM using a scan tool.

Yea, unfortunately I don't have a flasher so I have to pay way more than I paid for the part for them to let the machine do a half an hour of programming, but it is what it is. I just got the part in today so I will update you after I have it in if the hard shifting has gone away or not.

I am pretty sure I have seen the TCM when I have been replacing other parts on the car. but I am having trouble finding any literature or videos showing the location of it. it's in the front of the car right? On the driver's side basically in parallel with the serpentine belts (as far as location) next to the empty battery tray?

Not a problem. Here is the procedure. Its pretty light on details but shows a pretty good picture.

Okay, thanks. that is where I thought I had seen it at. just wanted to make sure.

No problem. Please let us know if you need anything else. Thanks

Is it normal for the car to act weird after the TCM is programmed. When I drove it home from the shop that programmed it, the car drove great. Then this morning when I was driving down the road, the check engine light suddenly came on, my stabilitrak was off/said service stabilitrak, and it said I was losing engine power and I couldn't drive over like 20 mph. I got the codes checked and it was throwing codes for the throttle body and accelerator pedal, but I have recently replaced both of those along with the sensors. So I unplugged the battery to reset the codes and it happened again when test driving it. I reset the codes a second time and now it is driving fine. So I'm not sure if that is normal or if I may have another problem..

You could have another issue. Clearly this is not normal after the TCM is programmed but it sounds like the throttle needed to be relearned. If the vehicle is driving fine, then clearly we don't need to do anything with it right now.

IF it acts up again, get the codes and send them to me before you reset it. Hold off on clearing them until we can get a handle on what may be happening. Thanks

Okay, thank you. I was not thinking it was normal but was confused it was giving me codes for parts I had recently replaced. I will let you know if it happens again. Thank you.

It happened again this morning, there is two different codes but a total of 4. C0242 and P2135 (×3).

Do you think I have a bad engine control module?

Or a bad PCM? I know these modules rarely fail, but I am not sure what else the problem would be. The parts for the other codes were recently replaced.

So it looks like these are new? If so, I think you have a wiring issue assuming each of the components have been replaced. Maybe you told me but have you replaced the throttle body? Even if you have, if you look at the chart for P2135, it says that this code is set when there is high resistance. Clearly this doesn't tell you where but it tells you what you need to focus on when testing these circuits.

What wiring repairs have you made to this point? I would unhook the wiring from the throttle body to the ECM and measure resistance on these wires.

Yes, I have replaced the throttle body with new sensor, accelerator pedal that came with sensor, and transmission input sensor...I also wired in new connectors for the throttle body and the transmission input sensor..there is only the one connector for the throttle body so what wires do I need to check?..and yes, these are new codes, before I replaced the TCM the codes coming up were P0700, P0716, and P0717..after I replaced the TCM these codes came up C0242 and P2135 (x3).

All of the resistance readings for both the throttle sensor and the ECM were overloaded except for the ground on the throttle sensor was at 1 ohm. The voltage test on the reference terminal 3 of the ECM was less than 1 volt. The throttle sensor voltage would jump up quickly to 2.5 volts then go back to 0.

So what does this mean and what do I need to do to fix it? I wasn't able to visually inspect the ECM circuit board to see if it was damaged because it had a sealant around the edges. After disconnecting the TPS and ECM/PCM connectors to do the voltage/resistance readings and plugging them back in the car is driving horrible again, it died when I tried to start it the first time, stabilitrak/traction control warnings are back on, and it is shifting hard..hoping to get this fixed ASAP.

When you say the resistance readings were "over load" do you mean your meter said "OL"? If this is the case then that means out of limit, in other words, you have an open. So if you unhooked from the ECM and the throttle body and measured the resistance on the same wire it is was open then that is your issue. You need to have continuity or less than 1 ohm of resistance. If you have an open on these wires that means the wire is broken or you were not on the same wire.

If you look at the wiring diagrams, you need to measure each wire one at a time from end to end.

Yes I meant OL..I grounded the negative prong on the car battery negative and used the positive prong to measure each wire individually..all of the wires read OL except for the ground which was at 1 ohm..and like I said earlier, the voltage readings on the throttle body jumped up to 2.5 volts and went back to 0.

Okay. So you checked them for a short to ground. That is correct then.

When did the voltage jump to 2.5V and back to 0? Were you operating the throttle? Maybe get a video of this and show what you are measuring so we can get on the same page. Sorry, electrical is the hardest thing to help when not being at the car with you.

No I was not operating the throttle. Am i able to operate the throttle with an electric throttle body that doesnt have a cable operator? When I touched the prong to the wire it jumped up to 2.5 volts then went to 0, it took like a second, didnt hold at all. It is dark out right now so I'm not sure I can do a video until tomorrow morning.

Also, from the diagrams, how do you know which is the top prong and which is the bottom prong?

Sorry for the long video, I wanted to make sure I got everything in there, needing to get this fixed ASAP, so hoping you are able to help me with this with what I gave you.

It would not let me attach the whole video in one, so I cut it into 4 videos, hoping this works for the upload so I dont have to make it choppy. This one is of the throttle body sensor.

ECM test.

Second test on throttle body sensor after plugging ECM back in.

How car acts after I plug everything back in.

Okay, so after finally finding a gm diagram I see that the terminals I tested on the video for the ECM were incorrect, but testing the correct terminals yielded the same results as seen on the videos, all resistance readings were OL. terminal 3 reference depending on how the paperclip was positioned and I was able to use 2 hands and hold it down, it would either jump up to 0.3-0.5 volts and go to 0 V or it would jump to around 0.1 V and hold at 0.02-0.03 V..terminal 2 reference would jump to around 0.05-0.1 V and go to 0 V, would not hold at any voltage..also on the one of me starting my car, I realized I had forgotten to re-plug the air intake sensor, so now it is starting fine and stabilitrak/traction control warnings are gone but check engine light is still on.

Sorry for the back to back, I should have looked at the diagrams more thoroughly before going out and testing again, it looks like you gave me the terminals for an 80-way ECM harness and I have a 73-way harness which I do not see even has a TP sensor signal terminal on it..I've attached the diagrams but I'm sure you know what I'm talking about, either way something is up and I'm hoping I gave you enough information. i am needing to get this fixed this weekend, so I'm hoping this works out.

Sorry, one more message, after finding out the correct 5 V references I went out again to check, I was able to get the wire cover off this time, terminals 33 and 34 would not register with just the prong, but with the paper clip would jump less than 0.1 V and go back to 0 V wouldn't hold, terminals 36 and 56 would jump to around 0.06 V with just the prong and hold and 0.03-0.04 V and with a paper clip would jump to 0.1-0.2 V and would hold at 0.03-0.04 V.

The voltage jumping up and going back to 0 like that is due to the probe moving and it creating its own voltage. Once it settles down and goes to 0 that is your reading. So all of those appear normal because the sensor was not plugged in.

At this point we need to go back to the P2135 and use a scan tool. Does your tool read data or is it just a code reader?

We need monitor what the sensors are telling the PCM when everything is hooked up and the only real way to do this is to monitor the PCM data.

Here is the testing that we need to stick too.

FYI - when you ohm out a wire you want to be on the wire by itself and unhooked at both ends. You do not ohm out wiring that is connected to voltage because that won't show you anything. Basically you are testing the integrity of the wire only. You can "practice" this by taking a 12 inch piece of wire and touch your black lead to one end of the wire and the red lead of your meter to the other end and you should have less than .5 ohms. This is ohming out a wire.

Was I not doing it right by having it grounded while the car was off for reading the resistance?

If you say the readings seem normal, shouldn't they have been jumping to 5 V and going to 0 V and not less than that?

What do you mean when you say the sensor was not plugged in? On the videos I watched where they were testing these the voltage held even when it was not connected to the sensor and it held at 5 V, but it's normal for how it was acting when i did it reading the voltage of the connector?

Was that not the testing procedure I was following by having it grounded? As I said before also, I have a 73-way ECM connector, and from the gm diagram I sent you, there is no TP sensor wire in the ecm connector, that is in the 80-way connector, terminals 63 and 65 on mine are different..

I do not actually have a code reader myself, I go to the parts store and have them read the codes, it gives some suggested sources of the problem but I'm not sure that it reads any data...

What should I do from here then?

Correct. Resistance readings are wire end to wire end. You were checking for shorts to ground. It is a good test but just not a resistance test. If you are checking for a short to ground that means your wire is touching ground when it should not. Basically only ground wires should be touching ground. If any others have resistance to ground then they are shorted.

As for testing the 5 volt reference you would do it just like you are however, that is not your issue. Your issue is that the throttle position sensors are not reading within spec. So that means we need to monitor it with a scan tool because they need to be plugged in.

I hate to tell people this but I think we need a shop to look at it because I don't have a way to tell you to properly test this from here. You have proven out the wiring so we need the scan tool to see what is out of whack.

Oh I see..the video I watched he tested the resistance with it grounded to the battery, so i thought that's what i was needing to do, but makes sense now since the only resistance reading I was getting was on the ground lol..but where would I even check the resistance on the throttle sensor since my ecm harness doesnt have tps sensor wires on it?

Do you mean checking the voltage on the throttle body when it is plugged in? Or getting some other type of data from it?

Yes. We need to check the voltage when it is plugged in but we need to do that with a scan tool that is able to read the data from the PCM.

As for your wiring diagram that doesn't show a TPS in the PCM, that doesn't seem possible because the PCM would have no way of reading it which would prove the sensor pointless.

I am not sure what is happening with that so if you don't have a scan tool, our best option at this point may be to have someone look at it.

Oh ok, I was just looking at those GM diagrams that I attached on the previous comment and I didnt see any tps sensor ports in the 73-way harness like there is with the 80-way, so I was just confused by that.

Yes, I dropped the car off this morning for a diagnostic and they had it all day and couldn't find the problem, said they are going to keep looking at it on monday to try and find the problem. They said it was giving the codes that I previously told you: P0716/717, C0242, P2135, but they said they were also getting some U codes. Apparently they are having trouble finding the source of the problem.

Yeah. I can't explain why it is not listed. I can only imagine they call it something different on that list.

The fact that it is throwing some U codes points to a wiring issue. Those are normally communication faults so it will be interesting to see what they come up with.

Thanks for the update.