Hi all, I've just registered on the forums and this is my first posting. I found the site through a google search for "hummer h3 check engine light" and did as thorough a search as I could for postings similar to what I'm experiencing.

Tonight I got into my 2007 Hummer H3 (6800 miles) and the check engine light appeared and didn't go off. I called up OnStar and had them run a remote diagnostic. The woman at OnStar told me that the warning they were picking up on was related to the fuel system. She speculated that it was due to the gas cap not being reattached properly after the last visit to the gas station and that it was "not a big problem." She recommended I turn off the car and replace the gas cap properly. After which, the check engine light should go out (after a short time). I was instructed that after starting the engine 7 times, if the check engine light did not go out, to take it in for service. Well, 7 times has come and gone and I still have a check engine light. I'm going to take it into the dealership tomorrow, but I thought I'd run the full situation by you all first. Read on....

Every so often, when I start my H3, the engine will sound excessively loud. It's almost as though it's running on fewer cylinders than it should. I'd describe it as kind of an airy sound, I wish I could give a better description than that. The problem goes away after a short time driving, but it did happen earlier today (Before the check engine light came on). I've read up on the infamous head replacement issue that some seem to be having and I'm obviously concerned. I don't notice it driving poorly or making any funny noises otherwise though, so I'm not sure what to make of it. Any ideas?

I have one other small issue and I wonder if anyone else notices this. Every once in a while, my brake pedal feels a little loose and it rattles. Every few seconds I'll feel a bit of a "click" vibrate through it. It's an intermittent problem, so explaining it to the dealer might be hard. If I turn off the engine and immediately restart the problem does not go away, but if I leave the car off for more than a few minutes, it's fine again.

If any of you have any insight into any of these issues, I'd be greatly appreciative to you if you'd share.

For the record, I've had my H3 since February '07 and I love it. It's Black, with the chrome package and moonroof. Single Disc CD with XM radio. I added an iPod controller to the factory stereo (Al & Ed's Autosound) and can control the iPod on the head unit now (next track, previous track, volume). I keep the iPod in the center console where it charges. It has a long enough cable for me to comfortably change artists or use it (safely) as I drive. I also added the OEM mud flaps after driving it around for a few weeks with constant splash on the doors. Initially, I purchased the vehicle with fabric seating, but had leather interior (black with grey piping and the word HUMMER embroidered in grey on the back of both front seats) installed through the dealership. The seats are still manually controlled and they don't heat, but I live in L.A. and am tall enough to just slide the seat all the way back anyway. Good deal for me. I'm very happy with the quality of the aftermarket leather install. I recommend it if you're thinking about it.

Here's a pic I took the day I bought it. I'll try to get a pic of the interior for you all to see.




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Long post! But here's some ideas -

My guess on the check engine light is the gas cap -- but not that its not on properly, but probably just a bad sensor thinking that it isn't. The dealer should be able to fix that pretty easily and quickly.

The loudness of the engine is on every H3, especially on cooler start-ups (very first one of the day, after its been sitting for a while, etc). Mine normally goes away after about 200 feet of driving - no big deal and not related to any of the head problems.

The brake sounds a little weird -- I'd have the dealer take a look. Sometimes you get a click when either a) the ABS engages and you get a grind or b) you get a click when the traction control kicks in, but that's through the gas pedal. Is it during heavy braking or just normal?

 

As for the gas cap issued. The light should turn off after three ignition cycles, not seven key on/engine off cycles. Igition cycles are dependent upon engine temps, and a decent example is from a cold engine startup, until the engine reaches a specific engine coolant temperature, back down to a cooled down engine coolant temperature. Therefore, the answer Onstar should have given you was wait about a week and see if the light goes off and stays off. If so, chances are it was not installed correctly after a fill-up.
Most of the time, this is the problem. If your vehicle had 30K on it, I might say it could also be a bad gasket/seal in the cap.

Asto the click through the brake pedal it could be the assist motor kicking in giving you some feedback via the brake pedal. (The H3 uses a high pressure motor and accumulator for brake boost instead of vacuum as used on other vehicles.) Also, you might feel a slight kickback of the brake pedal during initial start and movement of the H3. All GM ABS systems perform a self-test at around 3 mph after initital startup. This is used to test all the internal solenoids. You will also have a kickback feeling if you go into ABS operation or traction control operation. However, you should know if you are in TC or ABS operation mode due to the vehicle's operating condition.
The looseness in the brake pedal could be a bad bushing that is rotating and sometimes out of alignment.

 

Thank you for the information. Sorry about the long winded post, but I wanted to be as descriptive as possible.

The engine light is still on as of this morning, but it hasn't been through 3 ignition cycles as you've suggested f5fstop. I've got an appointment at the dealership a bit later to have it checked out, so whether it's a bad sensor or just needs a couple more ignition cycles will hopefully be clarified then.

The loudness issue being common is a bit of a relief. As with yours Hummer Guy, mine goes away after a very short distance driving and most commonly happens after a cold start.

The brake issue happens occasionally from the moment I start the car. As f5fstop mentioned, sometimes I feel a "kickback" feeling from the moment the vehicle starts...sometimes I won't. Every so often (every 25-30 starts or so), I get the rattling brake pedal. I'm guessing the ABS or traction control is to blame as you've suggested, but I'm not sure why. I'll have the dealer look at it, though I imagine they won't know what to make of it until they can experience it for themselves. The brakes work fine when this happens and aside from it being annoying, it doesn't affect driving conditions at all. It happens at all speeds, but is especially noticeable at slow speeds.

Thanks again for the responses. I'll keep you posted as to what the dealer says.

 

Well, you were absolutely correct about the engine light. It shut off by itself today after running for 3 or 4 minutes. I had to move my dealer appointment to tomorrow, so I'll ask about the brakes then. I'm due for an oil change anyway, so I may as well address it now before it becomes a real problem.

Thanks again.

 

What did you add from Al & Ed's Autosound to integrate your iPod into your head unit? Is it on their website?

 

I do not have the exact part name, but they should be able to tell you over the phone what they can do. If you have a "BAND" button on your head unit, your vehicle is capable of having the iPod interface installed. They connect it through one of the inputs in back (in my case XM1). It will allow you to control the iPod to a limited degree (next track, previous track, volume) and it will also charge the unit. It won't show you any track information on the head unit's screen, nor can you change artists without doing it manually on the iPod (unless you are in shuffle mode). I'm inclined to say it was somewhere in the vicinity of $150 installed. Not cheap, but it works well. I wish I'd spent the money toward a double DIN DVD unit that would let me scroll through my artists. It's a considerable amount more money to do this, but it'd be a fun toy...even if I'd never get to watch a DVD (I always drive).

I'll grab some pics of the interior of my H3 and start a new thread in the vehicle showoff section. I don't want to go too far off topic in here.