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Super mechanic
Super mechanic, ASE Certified Technician
Category: Saturn
Satisfied Customers: 17218
Experience:  ASE Master tech, 30 years experience
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2008 Saturn: 3.5L V6. 62k miles..idle rough..500 rpm

Resolved Question:

2008 Saturn Aura 3.5L V6. 62K miles. several weeks ago started to idle rough all the time. bouncing off 500 rpm. no engine warning lights. starts fine no stalling, and no problems at speed just idle. I put some fuel injector cleaner thru 2 tanks in a row.
Submitted: 5 years ago.
Category: Saturn
Expert:  Super mechanic replied 5 years ago.

Hello and welcome to Pearl/Just, Super mechanic here. I will do my best to help you with your question. My goal is to help save you money and I hope you will be completely satisfied with my answer. If you need any more on it just let me know.


About your vehicle.


Throttle Learn


The engine control module (ECM) learns the airflow through the throttle body to ensure the correct idle. The learned airflow values are stored within the ECM. These values are learned to adjust for production variation and will continuously learn during the life of the vehicle to compensate for reduced airflow due to coking. Anytime the throttle body airflow rate changes, for example due to cleaning or replacing, the values must be relearned.
A vehicle that had a heavily coked throttle body that has been cleaned or replaced may take several drive cycles to learn out the coking. To accelerate the process, the scan tool has the ability to reset all learned values back to zero. A new ECM will also have values set to zero.
The idle may be unstable or a DTC may set if the learned values do not match the actual airflow.



Without Scan Tool - Learn Procedure

Important: Do NOT perform this procedure if DTCs are set.

  1. Start and idle the engine in PARK for 3 minutes.
  2. With a scan tool, monitor desired and actual RPM.
  3. The ECM will start to learn the new idle cells and Desired RPM should start to decrease.
  4. Ignition OFF for 60 seconds.
  5. Start and idle the engine in PARK for 3 minutes.
  6. After the 3 minute run time the engine should be idling normal.

Important: During the drive cycle the check engine light may come on with idle speed DTCs. If idle speed codes are set, clear codes so the ECM can continue to learn.

¤ If the engine idle speed has not been learned the vehicle will need to be driven at speeds above 70 km/h (44 mph) with several decelerations and extended idles.
  1. After the drive cycle, the engine should be idling normally.
¤ If the engine idle speed has not been learned, turn OFF the ignition for 60 seconds and repeat step 6.
  1. Once the engine speed has returned to normal, clear DTCs and return to the diagnostic that referred you here.

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