Computer Relearn Procedures: Overview Chevrolet Tahoe II

Description

Automatic Temperature Control (ATC) module must be reset or recalibrated each time a door actuator is replaced or when ATC module is replaced. It is necessary for ATC module to learn feedback voltage values for each door stop position for all doors in front HVAC unit housing and rear HVAC unit housing. If an actuator blend door, mode door, or if recirculation door, or door actuator are out of calibration, ATC system will not perform at maximum efficiency.

1. Turn the ignition switch to the ON position. Simultaneously depress and hold the Power and Recirculation buttons on the heater-A/C control for at least five seconds. The manual heater-A/C control power Light Emitting Diode (LED) and Recirculation LED, or the Automatic Temperature Control (ATC) heater-A/C control Delay and Recirculation graphics will begin to flash when the calibration procedure has begun.
2. The calibration procedure should take less than two minutes to complete, for the manual heater-A/C control, and less than twenty seconds for the ATC heater-A/C control. When the LEDs or graphics stop flashing, the calibration procedure is complete.
3. If the LEDs or graphics continue to flash beyond the normal three minute (manual) or twenty second (ATC) calibration time, it indicates, that the heater-A/C control has detected a failure and a Diagnostic Trouble Code (DTC), has been set. Use a DRBIII® scan tool to perform further diagnosis.
4. The LEDs or graphics will continue to flash, even after the ignition switch is cycled Off and On, until a successful calibration is completed or until the vehicle has been driven about 8 miles. For diagnostic procedures for calibration test failure, see SELF-DIAGNOSTIC SYSTEM in appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING.

Any time a power liftgate component is removed, replaced, liftgate adjustment is performed or diagnostic trouble codes are addressed and erased, a learn cycle must be performed. This learn cycle enables the power liftgate control module to learn or relearn its critical information (travel limits, resistance to door travel, etc.) which allows it to perform properly and safely. It also tells the technician that the system is performing properly and is able to be returned to service.

1. Connect the DRBIII® scan tool to the Data Link Connector (DLC), located on lower left edge of instrument panel. Turn ignition switch to ON position. Check for power liftgate door codes (fault messages). Clear any DTCs that are set.
2. Operate power liftgate and recheck for DTCs. If any DTCs exist, diagnose and repair as necessary before performing the learn cycle. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. If DRBIII® scan tool is not available, the learn cycle can be performed by opening and closing the power liftgate using any of the normal open/close command switches. Be certain to cycle the liftgate through a complete open and close cycle or the procedure will not be complete.
4. Using the DRBIII®, go into the Test Routine Menu and select a power open command.
5. Using the DRBIII®, select a power close command.
6. The power liftgate learn cycle is complete. If power liftgate door does not fully open or close, a problem still exists. Diagnose and repair as necessary.

Any time a power sliding door component is removed, replaced, door adjustment is performed or diagnostic trouble codes are addressed and erased, a learn cycle must be performed. This learn cycle enables the power sliding door control module to learn or relearn its critical information (travel limits, resistance to door travel, etc.) which allows it to perform properly and safely. It also tells the technician that the system is performing properly and is able to be returned to service.

1. Connect the DRBIII® scan tool to the Data Link Connector (DLC), located on lower left edge of instrument panel. Turn ignition switch to ON position. Check for power sliding door codes (fault messages). Clear any DTCs that are set.
2. Operate power sliding door and recheck for DTCs. If any DTCs exist, diagnose and repair as necessary before performing the learn cycle. See appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.
3. If DRBIII® scan tool is not available, the learn cycle can be performed by opening and closing the power sliding door using any of the normal open/close command switches. Be certain to cycle the sliding door through a complete open and close cycle or the procedure will not be complete.
4. Using the DRBIII®, go into the Test Routine Menu and select a power open command.
5. Using the DRBIII®, select a power close command.
6. The power sliding door learn cycle is complete. If power sliding door does not fully open or close, a problem still exists. Diagnose and repair as necessary.

The Transmission Control Module (TCM) employs a strategy which modifies Torque Converter Clutch (TCC) operation. This strategy conditions the TCC disc for optimum converter clutch engagement and feel throughout the life of the transaxle. The cycle inhibits Full Electronically Modulated Converter Clutch (FEMCC) until six hours of Partial Electronically Modulated Converter Clutch (PEMCC) operation have taken place, or the vehicle has been driven 3750 miles. The cycle automatically terminates when either the time or mileage has been achieved, however, the mileage may vary slightly from vehicle to vehicle. The TCC break-in cycle must be restarted using the DRBIII® scan tool, and upon the following

1. Replacement of TCM on vehicle with less than 3750 miles or less than 6 hours of PEMCC operation.
2. Replacement of torque converter assembly at any vehicle mileage.

This procedure is used to properly condition TCC to prevent shudder during clutch engagement. Break-in procedure must be used if torque converter is replaced at any vehicle mileage, or PCM is replaced with vehicle mileage less than 3750 miles.

Break-In Procedure

Connect scan tool to data link connector located below instrument panel, near steering column. Follow scan tool prompts to TCC BREAK-IN, in the TRANSMISSION CONTROL MODULE/MISCELLANEOUS section. View or Start procedure as commanded by scan tool.

Flash Electronically Erasable Programmable Read Only Memory (EEPROM) is contained in an Integrated Circuit (IC) inside of Powertrain Control Module (PCM). The EEPROM contains the vehicle strategy and any calibration information specific to vehicle. The IC is reprogrammable and at times it may become necessary to reprogram or reflash the entire contents. This is usually due to an after production strategy change or the Flash Vehicle Identification (VID) Block has been previously reprogrammed and has reached its limit. The VID block can be tailored to accommodate various hardware changes made since vehicle production. This procedure can only be performed using Ford's Service Bay Technical System (SBTS) or equivalent.

A replacement PCM will have a label stating PROGRAMMING REQUIRED. This indicates that it is necessary to retrieve VID data from the original PCM before removing PCM from vehicle. This procedure can be performed using New Generation Star (007-00500) scan tool or equivalent. See FLASH VEHICLE IDENTIFICATION (VID) BLOCK PROCEDURE . If original PCM is damaged, nonfunctional or incapable of communicating, it will be necessary to manually reprogram VID block. This procedure can only be performed by contacting the "AS BUILT" data center for programming information.

Flash Vehicle Identification (VID) Block Procedure

Note. If using a generic scan tool, follow scan tool manufacturer's instructions to perform FLASH VEHICLE IDENTIFICATION (VID) BLOCK PROCEDURE.

1. To perform this procedure NGS scan tool, Ford Service Function (FSF) card and NGS Flash Cable (007-00531) must be used. Plug flash cable into scan tool. Plug other end of flash cable into Data Link Connector (DLC). From the scan tool main menu, select SERVICE BAY FUNCTIONS, POWERTRAIN CONTROL MODULE and then PROGRAMMABLE MODULE INSTALLATION.
2. Scan tool display should show 2 selections. The first is selection is for old PCM information to be retrieved and stored. The second selection is for restoring new PCM with information that has been retrieved from the old PCM. Follow scan tool display instructions or refer to instruction sheet included with FSF card. If Flash Vehicle Identification (VID) Block has been reprogrammed previously, scan tool will display a message indicating the need to reflash entire Integrated Circuit (IC). This procedure can only be performed using Ford's Worldwide Diagnostic System (WDS).

Overview

This procedure quickly optimizes shift quality. Procedure must be performed after disconnecting battery or loss of voltage supply to TCM, replacing TCM, transmission internal components, solenoid assembly or torque converter. DRBIII® scan tool with proper cartridge must be used to perform shift quality quick-learn procedure.

The following conditions must be met when performing shift quality quick-learn procedure: oil temperature must be greater than 60°F (16°C), brakes must be applied when indicated, engine speed greater than 500 RPM, throttle angle less than 3 degrees, gearshift lever must be in Neutral and moved only when indicated, gearshift lever must remain in Overdrive as indicated until DRBIII® indicates procedure is completed.

It is imperative that vehicle be shifted into OD with engine running and ensure fluid level is correct. This will purge air in clutch circuits to prevent erroneous clutch volume values, which could cause poor initial shift quality.

If unused replacement TCM is installed on vehicle with engine at normal operating temperature, shift quality quick-learn procedure will cause TCM to indicate a cold oil temperature. Oil temperature must be monitored with DRBIII®. If oil temperature is less than 60°F (16°C), allow engine to idle until oil temperature is greater than 60°F (16°C). If oil temperature is greater than 200°F (94°C), allow transmission to cool until oil temperature is less than 200°F (94°C).

Quick-Learn Procedure

Connect DRBIII® scan tool to DLC. Using proper cartridge and DRBIII® manufacturer's instructions, move through program to enter 45RFE or 545RFE menu. Start vehicle. Select TRANSMISSION, and then MISCELLANEOUS functions. Apply brakes. Select QUICK-LEARN function. Follow manufacturer's instructions displayed on DRBIII®. After quick-learn procedure is completed, perform DRIVE LEARN PROCEDURE (GRAND CHEROKEE & LIBERTY) .