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I just finished a ton of work on my son's 2003 civic. New radiator, timing belt, refurbished head, etc. it starts and runs great...for a few minutes; then rpm goes up to 2100 or so and i get p1505 and p0505 codes. Could this be caused by coolant not beong bled properly yet?

 
Rep Power: 518

Vacuum leaks, more likely

 
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well...i bled out a bunch more bubbles and took it for a test drive. been running 15 or 20 minutes and so far so good.

 
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It's running well, but still giving me the codes. I'll check all my vacuum hose connections..

 
Rep Power: 518

Listen for sucking (hiss) sounds, and idle RPM higher than normal

After you solve the codes, make sure to do an idle relearn

 
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That's the thing, though. Idle rpm is spot on now. Car is back in son's possession, but I'll check with him later this week and see if the code posts again.

 
Rep Power: 518

Did you erase the old codes?

 
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Check for poor connections or loose terminals at the IAC valve (and at the PCM) as well.

Check the PCV valve and its hose for leaks.

 
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Thanks. Will do. May take the iac off and clean it out really well, too. I'm thinking I dislodged some crap by trying to clean out the throttle body when everything was off for the head replacement.