heater works when engine is running at high rmp's but cold otherwise

2004 HYUNDAI ELANTRA
126,000 MILES
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HBBOLDING
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I have a 2004 Hyundai Elantra. The heater will put hot air out at high RPM, but cold air at low RPM. The check engine light came on, had a code of 128. I replaced the thermostat and engine coolant sensor, had the light turned off. 4 days later, the engine light is back on with a 128 code. Heater, same condition as above. Do you have any suggestions as to what the cause is??Thank you in advance.
Dec 28, 2011 at 11:08 PM
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HMAC300
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check to seeif your coolantlevel is full. a low level will caue the code you are having. it may have worked airout of the sytem and dropped the leve of coolant. that could cause your heating problem.
Dec 28, 2011 at 11:14 PM
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HBBOLDING
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Water level is where it is supposed to be
Dec 29, 2011 at 11:48 PM
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HMAC300
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you'll have to have it check ed to see if there is abad connection, corrosion or a wire chafed and rubbing someplace.
Dec 30, 2011 at 4:15 PM
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