Chevrolet Equinox Service Manual: Q38 Throttle Body: Throttle/Idle Learn Engine Control Air Metering/Acceleration Throttle

Description

The engine control module (ECM) learns the airflow through the throttle body to ensurethe correct idle. The learned airflow values are stored within the ECM. These valuesare learned to adjust for production variation and will continuously learn duringthe life of the vehicle to compensate for reduced airflow due to throttle body coking.Anytime the throttle body airflow rate changes, for example due to cleaning or replacing,the valuesmust be relearned.

An engine that had a heavily coked throttle body that has been cleaned or replacedmay 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 ECMwill also have values set to zero.

The idle may be unstable or a DTC may set if the learned values do not match the actualairflow.

Conditions for Running the Throttle Learn ProcedureScan tool Idle Learn or Idle Learn Reset ProcedureDTCs-P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0120,P0122, P0123, P0128, P0171, P0172, P0174, P0175, P0201–P0208, P0220, P0222, P0223,P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277,P0279, P0280, P0282, P0283, P0300–P0308, P0351–P0358, P0496, P0601, P0604, P0606,P060D, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128,P2135, P2138,or P2176 are not set.Ignition ON, engine OFF.The vehicle speed sensor (VSS) is 0-km/h (0-mph).Service Bay/On Road Learn ProcedureDTCs-P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0116, P0117, P0118, P0120,P0122, P0123, P0128, P0171, P0172, P0174, P0175, P0201–P0208, P0220, P0222, P0223,P0261, P0262, P0264, P0265, P0267, P0268, P0270, P0271, P0273, P0274, P0276, P0277,P0279, P0280, P0282, P0283, P0300–P0308, P0351–P0358, P0496, P0601, P0604, P0606,P060D, P0641, P0651, P1516, P2101, P2119, P2120, P2122, P2123, P2125, P2127, P2128,P2135, P2138,or P2176 are not set.The engine speed is between 450–4,000-RPM.The manifold absolute pressure (MAP) is greater than 5-kPa.The mass air flow (MAF) is greater than 2-g/s.The ignition voltage is greater than 10-volts.Throttle LearnScan Tool Idle Learn or Idle Learn Reset Procedure – Performed after the throttlebody is cleaned or replacedIgnition ON, engine OFF, perform the Idle Learn or Idle Learn Reset in Configuration/Resetor Module Setup.Engine idling, observe the scan tool Throttle Body Idle Airflow Compensation parameter.The Throttle Body Idle Airflow Compensation value should equal 0-% and the engineshould be idling at a normal idle speed.Clear the DTCs and return to the diagnostic that referred you here.Service Bay/On Road Idle Learn Procedure – Performed after the ECM is programmed orreplaced

Note:Do NOT perform this procedure if DTCs are set. Refer toDiagnostic Trouble Code (DTC) List - Vehicle.

Engine idling for 3-minutes.Observe the scan tool Desired Idle Speed and the actual Engine Speed parameters.The ECM will start to learn the new idle cells and the Desired Idle Speed should startto decrease.Ignition OFF for 60-seconds.Start and idle the engine for 3-minutes.After the 3-minute run time the engine should be idling normal.

Note:During the drive cycle the check engine light may come on with idle speed DTCs. Ifidle 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 atspeeds above 70-km/h (44-mph) with several decelerations and extended idles.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-secondsand repeat step-6.Once the engine speed has returned to normal, clear DTCs and return to the diagnosticthat referred you here.