Hyundai Forums banner

2004 Sonata Fast Idle Problem

5K views 1 reply 2 participants last post by  sbr711 
#1 ·
I have a 2004 Sonata with a 2.4L engine. I recently changed the timing belt as preventive maintenance and am now having an issue a sustained fast idle that will not go below 1200rpm. Occassionally an error code P0507 (fast idle code will pop up on the OBD-II code reader following code reset and two fully warmed up drive cycles) but not always. The P0507 code and fast idle problem did not exist to the timing belt change.

I checked the timing marks for the Crankshaft, the two overhead camshafts, the balance shaft and the oil pump shaft and they are all dead on following the appropriate number of revolutions of the crankshaft index mark. I even took before and after photos and the positions are identical. I also confirmed that the tooth count and length of the timing belt was identical prior to installation.

I checked for vacuum leaks and found none. Vaccum holds steady at about 21 Hg on my vacuum guage. PCV valve and hose are functioning and leak free. I even had my mechanic do a vacuum smoke test and it also showed no vacuum leaks. He also checked that there was no air trapped in the cooling system where the temperature sensor is located and also ran ECM diagnostics. He found the Idle Control Motor at 20% during warm idle and that the LTFT will be in the negative during road testing (-3 to -11% and varying). That said there is no code indicating that the Idle Contol Motor (valve) is faulty.

Any thoughts?
 
See less See more
#2 ·
When you replaced timing belt, you did not unbolt the cruise module, so you pulled the jacket out of the threaded nut, thus putting excess tension on the cable and hold throttle open.

You will have to razor blade the plastic jacket off so cable will sit beck in the threaded adjuster thing to allow throttle to close.

0507 code is result of the goof up.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top