TCM Adaptation-948TE And 9HP48

The 948TE and 9HP48 Automatic Transmissions use a sophisticated shift algorithm that includes learned information so that the shift quality remains excellent even as the Transmission wears. This learned information is recorded in memory cells referred to "Adaptation Memory Cells". Each applied clutch records the amount of time it takes to fill the clutch (Fast Filling Counter/Filling Time) and the amount of pressure (Filling Counter/Filling Pressure) required to apply the clutches. The adaptation memory cells should be set to zero (0) on every new Transmission (in a new vehicle and/or when the Transmission is replaced for service) and when the Transmission Control Module (TCM) is replaced for service. In addition, the adaptation memory cells are set to zero (0) anytime the TCM is flashed, and when the TCM adaptation memory cells are cleared using the scan tool diagnostic scan tool (Via Quick Learn/Valve Body Solenoid Learn). Until the adaptation has been learned/relearned, the Transmission shift quality may not meet the customers expectations.

The following 948TE/9HP48 Clutch Application Chart will help in identifying the clutches that are applied in each gear. Keep in mind that shift quality is greatly affected by the timing of disengaging one clutch and applying another smoothly. If a clutch remains on too long, then harsh shifts can occur or if the clutch disengages too quickly, then poor shift quality can occur.

The adaptation memory cells appear on the scan tool for every clutch except the dog clutches. Each clutch will include:

• Fast Filling Counter = the number of filling time events that has taken place
• Filling Time = +/- number of ms (milli seconds) from zero (standard set value)
• Filling Counter = the number of filling pressure events that has taken place
• Filling Pressure = +/- mb (millibar)/PSI (Pounds Per Square Inch) from zero (standard set value)

If the adaptation memory cell "counter" is zero (0), then the adaptation memory cell has not been updated. It will take a minimum of two counts to improve shift quality and with each subsequent count, shift quality will improve even more. Shift quality with continue to improve until the count reaches five, at which time improvements will be negligible.

The Adaptation Drive Learn procedure is very sensitive to transmission temperature, transmission input shaft torque, and transmission turbine RPM. The Adaptation Drive Learn procedure must be performed at the following:

• Transmission Oil Temperature between 50°C (122°F) - 110°C (230°F).
• Transmission input Shaft Torque between 24 Nm (18 ft. lbs.) - 150 Nm (110 ft. lbs.) (will be monitored on the scan tool as Engine Crankshaft Torque).
• Transmission input shaft RPM 1100 - 2500 RPM (can be monitored by monitoring Engine RPM using the tachometer on the cluster).

The B AND C CLUTCHES ADAPTATION LEARN PROCEDURE affects the following primary shifts:

• Reverse Engagement
• 1-2 Up-Shift
• 2-1 Coast Down-Shift
• 2-3 Up-Shift
• 3-2 Down-Shift
• 4-5 Up-Shift
• 5-6 Up-Shift
• 6-5 Down-Shift
• 5-4 Power on Down-Shift
• 3-2 Down-Shift
• 4-3 Coast Down-Shift

B AND C CLUTCHES ADAPTATION LEARN PROCEDURE

1. With the Scan Tool, erase DTCs.
2. Setup the scan tool to display the Transmission Oil Temperature, Engine Crankshaft Torque, Turbine (Input) Speed Sensor RPM, and Clutch 'X' - Filling Counter for each clutch.
3. Drive the vehicle until the Transmission Oil Temperature is above 50° C (122° F).
4. Accelerate the vehicle moderately to seventh (7th) gear. It will be necessary to maintain seventh gear during this process by utilizing the Electronic Range Selector (ERS).
5. Drive vehicle at constant vehicle speed between 80 - 96 kph (50 - 60 mph).
6. Maintain seventh gear, steady pedal, and constant speed continuously for approximately 10 minutes while staying within the following conditions:
   • Transmission input Shaft Torque should be between 24 Nm (18 ft. lbs.) - 150 Nm (110 ft. lbs.) (will be monitored on the scan tool as Engine Crankshaft Torque)
   • Transmission input shaft RPM should be between 1100 - 2500 RPM (can be monitored by monitoring Engine RPM using the tachometer on the cluster)
7. Using the scan tool, inspect the Clutch - B and Clutch - C Filling Counter/Fast Filling Counter status.
8. Continue the drive adaptation procedure until Clutch - B and Clutch - C Filling and Fast Filling Counters are at least 2 or greater.
9. Proceed to the "D CLUTCH ADAPTATION LEARN PROCEDURE" below.

The D CLUTCH ADAPTATION LEARN PROCEDURE affects the following primary shifts:

• 1-2 Up-Shift
• 2-1 Down-Shift
• 6-7 Up-Shift
• 7-6 Down-Shift
• Drive engagement when rolling backwards (or in cases of spline locked dog clutch A)

D CLUTCH ADAPTATION LEARN PROCEDURE

1. With the Scan Tool, erase DTCs.
2. Setup the scan tool to display the Transmission Oil Temperature, Engine Crankshaft Torque, Turbine (Input) Speed Sensor RPM, and Clutch 'D' - Filling Counter.
3. Drive the vehicle until the Transmission Oil Temperature is above 50° C (122° F).
4. Accelerate the vehicle moderately to sixth (6th) gear. It will be necessary to maintain sixth gear during this process by utilizing Electronic Range Shifter (ERS).
5. Drive vehicle at constant vehicle speed between 64 - 80 kph (40 - 50 mph).
6. Maintain sixth gear, steady pedal, and constant speed continuously for approximately 10 minutes while staying within the following conditions:
   • Transmission input Shaft Torque should be between 24 Nm (18 ft. lbs.) - 150 Nm (110 ft. lbs.) (will be monitored on the scan tool as Engine Crankshaft Torque).
   • Transmission input shaft RPM should be between 1100 - 2500 RPM (can be monitored by monitoring Engine RPM using the tachometer on the cluster).
7. Using the scan tool, inspect the Clutch - D Filling Counter/Fast Filling Counter status.
8. Continue the drive adaptation procedure until Clutch - D Filling and Fast Filling Counter is at least 2 or greater.
9. If necessary, proceed to the "E Clutch Adaptation Learn Procedure" below.

The E CLUTCH ADAPTATION LEARN PROCEDURE affects the following primary shifts:

• 3-4 Up-Shift
• 4-3 Down-Shift
• PRNDL in DRIVE Position

E CLUTCH ADAPTATION LEARN PROCEDURE

1. With the Scan Tool, erase DTCs.
2. Drive the vehicle until the Transmission Oil Temperature is above 50° C (122° F).
3. Accelerate the vehicle moderately to third (3rd) gear. It will be necessary to maintain 3rd gear during this process by utilizing Electronic Range Shifter (ERS).
4. Drive vehicle at constant vehicle speed at 24 kph (15 mph).
5. Maintain 3rd gear, steady pedal, and constant vehicle speed continuously for a minimum of 1 minute, making sure engine speed is less than 2, 000 RPM while driving 24 kph (15 mph). This will require adjusting the gas pedal position to keep the engine speed below 2, 000 RPM.
6. After 1 minute of driving at 15 mph, bring vehicle to a stop, then proceed to 24 kph (15 mph) as described above and repeat 5 times.
7. Stop the vehicle and shift to PARK. Using the scan tool, inspect Clutch E Filling Counter/Fast Filling Counter status.
8. Continue this procedure until Clutch - E Filling and Fast Filling Counters are at least 2 or greater.