P0300 and P0128 - Page 2 - Hummer Forums - Enthusiast Forum for Hummer Owners

Hummer H3 For the Hummer driver who wants the rugged look and off road capabilities of the Hummer, but in a smaller size and with a more fuel economy friendly engine.

P0300 and P0128

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  #11  
Old 01-10-2013, 07:39 AM
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Originally Posted by qui View Post
I notice the same issue with the lights dimming and AC/heater running lower while braking, but I don't have any codes or a check engine light, and I'm not idling rough or having trouble starting. Are we likely experiencing the same issue?
I'm not really an expert when it comes to this, but I would say your issue is about the same... My idle was not really bad... Starting the engine up was fine too. The headlights and heater bogging down when stopping was a problem. I assume that cleaning the MAF and throttle body would really help your issue. It did mine even though I was showing codes as opposed to you not having any. Hopefully someone with more experience will chime in.

Cheers,
Matt
 
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  #12  
Old 05-01-2013, 10:49 AM
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I replaced my thermostat once the code P0128 came up and still engine light comes on. So I did the steps on this site H3 Throttle body and MAF sensor cleaning (up to step 5 (I couldnt get the vacuum hose on the intake loose so I left it as is) to clean the MAF sensor, and now I get different codes.(P0449) Would these codes have anything to do with messing with this vacuum hose or other sensors? TIA
 
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  #13  
Old 05-01-2013, 02:06 PM
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Originally Posted by 06redhummer View Post
I replaced my thermostat once the code P0128 came up and still engine light comes on. So I did the steps on this site H3 Throttle body and MAF sensor cleaning (up to step 5 (I couldnt get the vacuum hose on the intake loose so I left it as is) to clean the MAF sensor, and now I get different codes.(P0449) Would these codes have anything to do with messing with this vacuum hose or other sensors? TIA
A quick search of the forum database would have revealed to you a few possibilities that could be related to your recent maintenance: http://www.hummerforums.com/forum/hu...de-help-14854/

Otherwise, inspect the evap. solenoid in question. They are known to crack and erode surrounding the attached breather port.
 
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