Engine light linked to Cruise control not working? Help!! please?

Discussion in 'Chevy Trailblazer Forum (GMC Envoy)' started by Rhizzlebop, Aug 10, 2010.

  1. Rhizzlebop

    Rhizzlebop New Member

    So, I have the 04' with the I6. I bought it new in 03. Always been pretty darn reliable.

    My check engine light was on for a while and when I went for a code check it hit on 3 codes. This was checked at Advance and Oreillys.

    One code refers to the engine coolant temp being too low.

    The other two codes reference the engine fan RPM being too high.

    When the engine light first came on it was no issue. I was pretty sure it was the thermostat since it didn't warm up as much as it had done in the past. The cruise still worked then.

    It was a bit later, like a few months that the cruise stopped. It didn't work for a few days, then started working, then after a few weeks it stopped again and hasn't consistently worked since.

    Now, it'll work if I disconnect the battery for a while. When I reconnect it'll function as usual for a little while. Once it worked for 2 days, then this past weekend it worked for just 20 minutes.

    This past weekend I replaced the thermostat and the engine temp sensor. I reconnected the batt. and went for a drive. Cruise worked, no engine light, temp was warmer, right on the midline. Going down the interstate, the cruise just kicked off and wouldn't come on again. The next day the engine light came back on and hasn't gone out since.

    I am planning to go back and get the code scanned again to see what is hitting now.

    The codes that referenced engine fan being too high before mentioned the engine fan clutch and the engine fan relay. Well, I swapped the relay with another one a few weeks ago. Its still running in that configuration but made no difference in the results. So its apparently not a relay.

    The clutch seems ok. It comes on when the engine is hot at a stop light, and by third gear it cuts off. Feeling the fan, it has good resistance, but not locked down and not freewheeling.

    I'm not sure what else could be causing the engine light, but it seems to ALSO be disabling my cruise.

    Anyone ran into this issue yet?
  2. TMRuiz

    TMRuiz Rockstar 100 Posts

    It might be a total coincidence that the cruise started acting up while the light is on. You might have a problem with the cruise control switch itself. If it comes and goes whether or not the check engine light is on it may just be a bad switch. I’m not sure how to check that particular switch but it may be a different starting point for fixing your cruise control. Sorry I can't give you a better answer than that. Good Luck
  3. Rhizzlebop

    Rhizzlebop New Member

    It might be a total coincidence, but it can't be a mechanical switch failure and its not a fuse.

    Whenever the battery has been unplugged while working on the engine things, as soon as you reconnect it, the cruise works fine. Then, anywhere from 2 days to 20 minutes later, it stops working again. During those times, when you reconnect the battery the engine light is OFF and then comes back on at some point.

    Granted, the engine light being on and cruise stopping are not in direct correlation.

    I dunno what to think.

    ---------- Post added at 09:22 AM ---------- Previous post was at 08:33 AM ----------

    Another weird thing, if anyone is willing to comment. My air conditioner fan is making weird noises. It sounds like the bearing are going out on the fan. Sometimes it growls, sometimes it rumbles. It changes a little when I change fan speed. Sometimes it doesn't do it at all.
    The really weird part is this. If I start the AC and its making the noise, I can turn the AC fan off, and it'll stop.....for about 2 seconds, then it starts again. I can turn the AC fan on and it'll stop for about 2 seconds and then starts back. I can press the button that shuts off outside air (I think its like MAX) and it'll stop for a couple seconds and start back, I can turn that button back on and it stops for about 2 seconds and starts back.

    Its SOOO weird. Anyone had this happen?
  4. Rhizzlebop

    Rhizzlebop New Member

    I went by Autozone yesterday and got the code scanned again. Now its not hitting the one about engine coolant temp and nothing mentions the engine temp sensor anymore either. So I feel I made a good call in changing those out.

    However, its popping two codes that talk about engine fan RPM being too high.
    One specifically says, engine fan RPM too high when commanded 0%.
    Also, this morning, I heard it on on my way to work, and the engine temp was way down under 1/4 the way up.
    So, sounds like the fluid has gotten on the wrong side and not letting the fan fully disengage and thats firing the code.

    Anyone have anything to add?
    The codes mention the fan relay, but already swapped it with the headlamp module relay thats exactly the same and I'm getting the same issue. Seems nearly 0% chance that both thoe relays are bad. Especially since my headlights work.
  5. Rhizzlebop

    Rhizzlebop New Member

    Ok, So friday, I'm on the interstate driving out of town. I was in a little traffic before hitting the onramp. Temp is good. I hit the interstate and see the temp hand over a little. Prob at 215. It creeps on over towards 220. I hit the cruise, it works!!

    I kept watching it. Temp didn't go any further. Then it started cooling. It fell back to 210, and the cruise cut off.

    I think when it was warm, the computer was telling the fan to run, and it ran, so no code issue. When the engine cooled, the computer told the fan to stop, but it wouldn't fully stop, so it triggered the code and the cruise cut off.

    I remembered that a week ago when I first did the stat and temp sensor, I went off down the highway and it ran over warm, and the cruise worked, and as soon as it cooled back to 210, the cruise cut off then too.

    However, all that logic is out the window when I mention the fact that on Saturday and Sunday, the cruise worked perfectly for the first time in months now, and the temp was right around 210. I did drive home friday night at about 85 MPH. Could I have centrifugally thrown the fluid back to the right side of the clutch causing it to function correctly again for now?

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