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Cruise control and other problems (also serves as an "I'm new" post)

7K views 58 replies 9 participants last post by  Destram 
#1 ·
I just picked up a 2004 CTS-V last weekend, and I'm already having to go to the dealership. The cruise control turns on, but will not set the speed. I took it to the dealership, and a code came back for a bad clutch position sensor. So I had them replace it today, and before I got it back they said they want me to bring it back in Monday for them to run more tests on it because they think the ECM may be bad (I have no clue how they came to that conclusion or how I would be able to verify that either).

After I got the car back, I had expected the sensor being fixed would fix my cruise control problem (after reading threads saying that could cause cruise control to not work), but it still isn't working. Anyone have any other ideas for what would cause it to turn on but not set?

Also, when I bought the car, there was no DVD for the navigation, so I bought one on eBay that was supposed to be genuine. I got it in the mail today and put it in. When the map finally comes up, it shows the arrow for my location, but the map is completely glitched. I'm sending the DVD back for a refund, but do you think it was a disc error or the navigation in the car is bad? I didn't have a chance to try it when I bought it since there was no DVD.

Any input would be appreciated. I'm in college living in an apartment with no tools or space to work on my car myself, so I'm kind of at the mercy of the dealership, and I'd prefer to not be completely ripped off (though at $94/hour for labor, that's gonna happen anyway).

Here are some pictures if you're interested:



 
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#7 ·
Update: The day after I got my car back, the CEL came back on, and the same code was coming up saying the clutch position switch was bad. I took it back to the dealership today, and now they're telling me the PCM is not grounding the clutch position switch, and that I need a new PCM. They're saying it's $975.55 for parts and labor. That's ridiculous. I'm a college kid with limited income, so there's no way I can do that.

Edit: And since the same code is coming back, I have no way of verifying whether or not the switch was bad in the first place and if I wasted $250 to get it replaced.
 
#10 ·
Attached the troubelshooting information for DTC P0833.

Based on that troubleshooting sequence as well as the one for the cruise control system it seems very likely that the clutch position switch did not need replacing. For one thing, a defective clutch position switch typically causes occasional failures to start which you do not report having.

Secondly, although ECMs do fail, it is relatively rare. It is far more likely that the connections to the ECM are oxidized and not making good connection. Oxidation, as opposed to rust/corrosion, consists of a thin coating of oxidized metal sufficient to block the low voltage on which computer controlled cars depend. It is easily removed.

Finally, if it is the ECM you can get used ones in the aftermarket for far less money. You would however, have to have it flashed by a dealer.
 
#11 ·
Unless its under warranty, save yourself some major money and either go to a reputable shop that's NOT the stealership, or just search and ask around the forums and learn to troubleshoot and fix the problems yourself. These forums have saved me thousands of dollars over the years. For example, I replaced my clutch position sensor last year for about $40 and 45 minutes of my time, thanks to info from here and ls1 forums. Compare that to the $250 you just unloaded on the same "repair"...
 
#13 ·
I would try disconnecting the battery and removing the pcm connectors first and cleaning them with some good electrical cleaner and make sure they have a good connection and all the pins look good and nothing is out of place. You can get the cleaner for cheap and it's worth a shot.

Worst case scenario you could get hooked up from someone over on LS1tech for cheap probably but I would only do that after you ran thru the diag portion like darkman posted and was absolutely sure you know where the problem is.

This is where there is a big difference between being a parts changer and being a Technician. Most dealerships are becoming more and more of a parts changer type. It is sad but I see it all the time here at the shop.
 
#16 ·
Well I cleaned the PCM connectors and had the CEL cleared to see if it'll come back on. In the trip back from the shop, the light didn't come back on, but the cruise control still doesn't work, which leads me to believe the light will come back on. If that's the case, the cleaning didn't help it, so am I to assume the dealership is right and I do need a new PCM?
 
#19 ·
No, I didn't do that. I have limited tools (just a set of sockets, screwdrivers, and wrenches). I've never worked on my own cars. I figure I'm in college, so it's time to learn, but being in college, money is limited to run out and buy tools to do everything.
 
#21 · (Edited)
The check engine light came back on tonight.

It looks like I should pick up a scan tool and a DMM. I know I can get the DMM pretty cheap, but I'm not sure which scan tool to get. Do you have any suggestions for which scan tool I should get that will let me run the tests in the pdf (such as "use the scan tool to monitor the clutch pedal position switch parameter" and so forth)?

I'm going to go pick up the DMM tomorrow, but I'll probably have to come back to this thread asking for help. I have the DTC PO833 pdf, but some of the things it wants me to do are a in a foreign language for me since I'm not the most car savvy person yet.
 
#23 ·
I picked up a DMM today. I'm looking at this scan tool: http://www.ebay.com/itm/230946308690?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

That will do what I need, right? If so, I'm going to order it, and when it comes in, I'll go through the tests in the pdf and report back here. If it ends up saying I need to replace the PCM anyway like the dealership said, at least I'll have some new tools I'll get to use from now on.

Oh, off topic, but I picked up a better jack today, too. The one that comes with the car sucks haha.
 
#24 ·
Jacks are for raising and lowering the car, but don't ever crawl under a car held only by a jack or even jacks. Jacks can and will fail, even if relatively new. For working under the car get either jack stands (not expensive and easy to store) or Rhino ramps (still cheap but require more storage room).

The scanner you need to perform the tests in the PDFs is a GM Tech II Scanner and will cost several hundred dollars. If you look for these, be cautious - there are knock-offs in the market place (have "TechII in their name") that are not the same thing.
 
#25 ·
Oh yeah, I have jack stands. I was just saying the jack that came with the car is a pain to use, so I bought a better one so I can jack it up faster.

As for the scanner, I don't have several hundred dollars to spend on one (a quick search on eBay showed one up to nearly $700). So while it may not be as good as the one you mentioned, are you saying the one I linked to in my previous post will not perform the tests I need to do? If so, then I won't be able to perform the tests, and that leaves me back at the beginning where all I have to go off of is what the dealership said (PCM needs replacing).
 
#28 ·
Most of us here are in the same boat as you are in that very few of us own a GM TechII scanner. Many of us own the type of scanner at which you were looking, which is good for finding out what specific code is causing a CEL and for clearing those same codes to see if they reset. However, GM dealers are not the only shops that have GM TechII scanners and the same troubleshooting charts. So you could look elsewhere in terms of a shop. I generally rely on my dealer for the kind of probem you are having, but I trust my dealer not to "throw parts" at a problem and actually run all the test.

In your case, based on my reading of the troubleshooting procedure, it is clear that the two possible defective components were the clutch position switch and the PCM. However, it also appears likely that the dealer should have found the clutch position switch to be "good" if the real issue is the PCM. The fact that the dealer replaced the clutch position switch makes me suspect that thery are not going through the trouble shooting chart eliminating the other possible causes (bad wiring, shorts, etc.) that would remain after the clutch position switch was changed. I would at least get another opinion before paying big bucks for a PCM, especially since the car is still running.
 
#26 ·
You just need a scan tool that will show the right information which most any scan tool that will show live data should show the clutch switch. I am unfamiliar with that one you are looking at but if it does as the description advertises it should show you.
 
#29 ·
I just ordered the scan tool, and it should be here by next Tuesday. When it gets here, I'll go through the the tests. If I get to a part I don't understand, I'll come back here. You guys are more than helpful, and I appreciate it. It's good to be able to ask for help from people who have no reason to lie to me like the dealership does.
 
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