IDLE SPEED & MIXTURE
Idle speed and mixture are controlled by Powertrain Control Module (PCM). No adjustment is required. PCM controls Idle Air Control (IAC) motor for proper idle speed.
THROTTLE BODY MINIMUM AIRFLOW
NOTE: Throttle body minimum airflow procedure checks throttle body calibration for correct idle speed. Procedure may be used for idle speed problems caused by the throttle body. Throttle body minimum airflow procedure should be performed after all other diagnostic procedures have failed to produce results that indicate a throttle body related problem. Ensure IAC motor is operating correctly before performing this procedure.
1.Start engine and warm engine to normal operating temperature. Ensure all accessories are off. Shut engine off. Remove air duct at throttle body.
2.Disconnect vacuum line at PCV valve located in valve cover. Install .185" fixed orifice Air Metering Fitting (6714) into disconnected vacuum line in place of PCV valve.
3.Disconnect purge vacuum hose from passenger's side front corner of throttle body, next to MAP sensor. Place cap on vacuum hose fitting on throttle body.
4.Connect scan tool to Data Link Connector (DLC) located below driver's side of instrument panel, near steering column.
5.Start engine and warm engine to normal operating temperature. Using scan tool manufacturer's instructions, select SYSTEM TEST and then access the MINIMUM AIRFLOW display on scan tool. When accessed, scan tool will count down to stabilize idle RPM and display minimum airflow idle RPM. Minimum airflow idle RPM should be 500-900 RPM.
6.Shut engine off. If minimum airflow idle RPM is correct, throttle body is okay. Go to next step. If minimum airflow idle RPM is not within specification, using approved cleaner, clean throttle body and recheck minimum airflow idle RPM. If correct minimum airflow idle RPM cannot be obtained, replace throttle body. Go to next step.
7.Remove air metering fitting. Reinstall vacuum hoses as necessary. Reinstall air duct on throttle body. Remove scan tool.
Monday, February 23rd, 2009 AT 6:10 PM