1998 Saturn SL2 High Idle

1998 ALL OTHER MAKES ALL OTHER MODELS

SATURNMAN63

MEMBER
2 POSTS

HI I HAVE A 98 SL2 TWIN CAM, 44,000 MILES. IT REVS AT 2000 OR SO RPM. IT WAS AT 3000 UNTIL I CHANGED TPS SENSOR. I HAVE A CODE THAT READS 1509 BUT I CANT SEEM TO FIND WHAT THAT IS. ANY SUGESSTIONS?

Jan 22, 2007 at 1:34 PM

PEPPERMRJ

✓Experienced Mechanic
1,158 POSTS

DTC P1509 Idle Speed High - Idle Air Control (IAC) System Not Responding

The first thing to look for is the ECTS. They will fail and cause a high idle also. The plastic tip cracks. Replace it with an updated brass tipped sensor from saturn.

Check the IAC wiring. Make sure the connection is clean and tight. Sometimes they will get carboned up and can be cleaned along with the throttle body.

Good luck and let us know. :)

Feb 7, 2007 at 9:35 AM

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Suggested Repair

For code P1509 (idle speed high, IAC not responding), inspect the engine coolant temperature sensor for a cracked plastic tip and replace it with the updated brass-tipped Saturn sensor. Check that the IAC wiring and connector are clean and tight, and clean carbon from the IAC and throttle body.

Conversation Summary

The owner of a 1998 Saturn SL2 with 44,000 miles reports a high idle around 2000 rpm after replacing the TPS, which had previously idled near 3000 rpm, plus code 1509. The expert identifies P1509 as idle speed high with the IAC system not responding, and recommends checking the coolant temperature sensor, IAC wiring and connection, and cleaning the IAC and throttle body.

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1998 Saturn SL2 High Idle

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